How-To Tutorials

In this article by John Henry Krahenbuhl, author of the book, Learning Axure RP Interactive Prototypes, we will cover the following topics: Logo and links Global navigation Shopping cart Search (For more resources related to this topic, see here.) Logo and links To create our logo element, we will drag the Placeholder widget onto the Home page in the design area. We will then enable an OnClick interaction that will cause the Home page to open in the current window when the Placeholder widget is clicked. To create the logo element, perform the following steps: With the Home page opened in the design area, in the Widgets pane, click on the Placeholder widget. While holding down the mouse button, drag the Placeholder widget and place it at coordinates (10,20). With the Placeholder widget selected, type Logo. We will see Logo in the center of the Placeholder widget, like so: Next, we will name the Placeholder widget and add the OnClick interaction. With the Placeholder widget selected, perform the following steps: In the Widget Interactions and Notes pane, click in the Shape Name field and type CompanyLogo. In the Widget Interactions and Notes pane, click on the Interactions tab and then on Create Link…. In the Sitemap modal window, click on the Home page. You will see Case 1 added to the OnClick interaction, as follows: Axure has numerous point updates, and as a result, in the Widgets Interactions and Notes pane, your version may show Shape Name (or a similar label for the name field) instead of Shape Footnote and Name. We will now create three new links in our header using a Dynamic Panel and the Label widget. In the Widgets pane, click on the Dynamic Panel widget. While holding down the mouse button, drag the Dynamic Panel widget and place it at coordinates (570,10). With the Dynamic Panel widget selected, perform the following steps: In the Widget Interactions and Notes pane, click in the Dynamic Panel Name field and type HeaderLinksDP. In the toolbar, change the width w: to 300 and the height h: to 25. In the Widget Manager pane, we will see the following: In the Widget Manager pane, double-click on State1 to open it in the design area. With State1 selected, in the Widgets pane, click on the Label widget. While holding down the mouse button, drag the Label widget and place it at coordinates (80,4). With the Label widget selected, perform the following steps: Type Help. We will see Help displayed as text on the Label widget. In the Widget Interactions and Notes pane, click in the Shape Name field and type HelpLink. In the Widget Interactions and Notes pane, click on the Interactions tab and then click on Create Link…. In the Sitemap modal window, click on the Help page. Repeat step 7 twice to create two additional links using the following table for coordinates, text displayed, shape name of the label widgets, and create link: Coordinates Text displayed Shape name Create link... (140,4) Support SupportLink Support (220,4) Sign In SignInLink Sign In Slow double-click on State1 and rename it to Links. When renaming a dynamic panel state, if the state is currently selected (that is, highlighted in blue), you only need to slow click on the state name to rename the state. If the state is not currently selected, you will need to slow double-click on the state name to rename the state. We have now created the logo with three additional links. Our header should look like this: Next, we will add global navigation using the Classic Menu - Horizontal widget. Global navigation We will now add global navigation using the Classic Menu – Horizontal widget. Once we have added the Classic Menu – Horizontal widget, our header should look like this: Open the Home page in the design area. To create the global navigation element, perform the following steps: In the Widgets pane, click on the Classic Menu - Horizontal widget. While holding down the left mouse button, drag the Classic Menu - Horizontal widget and place it at coordinates (240,80). Right-click the first menu item labeled File, and in the flyout menu, click on Add Menu Item After. Your menu should look like this: Repeat step 2, adding one more menu item. You should now have a total of five menu items. Click on the first menu item to select it and type Women. With the menu item selected, perform the following steps: In the Widget Interactions and Notes pane, click in the Menu Item Name field and type HzMenuWomen. In the Widget Interactions and Notes pane, click on the Interactions tab and then click on Create Link…. In the Sitemap modal window, click on the Women page. Repeat step 5 to change the menu item displayed and menu item name for menu items 2–5 using the following table: Menu item displayed Menu item name Create link... Men HzMenuMen Men Kids HzMenuKids Kids Shoes HzMenuShoes Shoes Accessories HzMenuAccessories Accessories We have now created the global navigation with five menu items. Our header should now look like this: Next, we will add a shopping cart element using a Rectangle widget with a Text Field widget. Shopping cart We will now add a shopping cart element using a Rectangle widget and a special character for a shopping bag icon. Our shopping cart element will look like this: To create the Shopping Cart element, perform the following steps: From the Widgets pane, drag the Rectangle widget and place at coordinates (870,80). With the Rectangle widget selected, perform the following steps: Right-click on the Rectangle widget and click Edit Text. Type Shopping. In the toolbar, change the width w to 90 and the height h to 30. In the Widget Interactions and Notes pane, click in the Shape Name field and type ShoppingButton. In the Widget Properties and Style pane, with the Style tab selected, scroll to Alignment + Padding and change padding by changing the value of R to 15. From the Widgets pane, drag the Image widget and place at coordinates (937,85). With the Image widget selected, perform the following steps: In the toolbar, change the width w to 20 and the height h to 20. In the Widget Interactions and Notes pane, click in the Image Name field and type ShoppingBagIcon. Double-click the image and select the image you would like to use (that is, a shopping bag or shopping cart image). For our shopping bag icon, an image of a handbag emoji sized to 20 x 20 pixels was used. The handbag emoji as well as other useful emojis can be found at http://emojipedia.org. Next, we will add an expandable search text field element using a dynamic panel widget with two states. Search One popular design pattern is to use an expandable search text field. To accomplish this, we will use a Dynamic Panel widget labeled SearchDP with two states: Collapsed and Expanded. The Collapsed state is the default state and will contain a Text Field widget. The Text Field widget will respond to the OnMouseEnter interaction and will perform the following actions: Move the HeaderLinksDP (Dynamic Panel) in x: -80 pixels. Transitioning the Dynamic Panel to the Expanded state, using the slide left animation. Set focus on the Text Field widget labeled SearchTextFieldExpanded. To create the Search text field, Dynamic Panel, and States, perform the following steps: In the Widgets pane, click on the Dynamic Panel widget. While holding down the mouse button, drag the Dynamic Panel widget and place it at coordinates (790,10). With the Dynamic Panel widget selected, perform the following steps: Right-click on the Dynamic Panel widget and click on Order, then click on Send to Back. In the Widget Interactions and Notes pane, click in the Dynamic Panel Name field and type ExpandingSearchDP. In the toolbar, change the width w: to 170 and the height h: to 25. In the Widget Manager pane, double-click on State1 to open it in the design area. With State1 selected, perform the following steps: In the Widgets pane, click on the Rectangle widget. While holding down the mouse button, drag the Rectangle widget and place at coordinates (80,0). With the Rectangle widget selected, In the toolbar change the values of w to 90 and h to 24. In the Widget Interactions and Notes pane, click in the Text Field Name field and type SearchRectangleCollapsed. From the Widgets pane, drag the Image widget and place at coordinates (149,2). In the toolbar, change the width w to 20 and the height h to 20. In the Widget Interactions and Notes pane, click in the Image Name field and type SearchIcon. Double-click the image and select the image you would like to use (that is, a left-pointing, magnifying glass image). For our search icon, an image of a left-pointing, magnifying glass emoji sized to 20 x 20 pixels was used. This emoji as well as other useful emojis can be found at http://emojipedia.org. In the Widgets pane, click on the Text Field widget. While holding down the left mouse button, drag the Text Field widget and place at coordinates (80,0). With the text field widget selected, perform the following steps: In the Widget Interactions and Notes pane, click in the Text Field Name field and type SearchTextFieldCollapsed. In the toolbar, change the value of w to 65 and h to 24. Right-click on the Text Field widget and click on Hide Border. In the Widget Properties and Style pane, with the Style tab selected, scroll to Borders, Lines, + Fills. Click on the down arrow next to the paint bucket icon. In the drop-down menu, click on the box with the red diagonal line to indicate no fill. The fill drop-down menu with no fill selected looks like this: Right-click on State1 and click Duplicate State. Slow click on State1 and rename it to Collapsed. Slow double-click on State2 and rename it to Expanded. In the Widget Manager pane, double-click on Expanded to open it in the design area. With Expanded selected, perform the following steps: Click on the rectangle widget labeled SearchRectangleCollapsed to select it and perform the following steps: The SearchRectangleCollapsed widget is at coordinates (80,0) and is directly beneath the SearchTextFieldCollapsed widget at coordinates (80,0). Slow-double-click on the design area near coordinates (90,10) to select the SearchRectangleCollapsed widget. Once selected in the Widget Interactions and Notes pane, in the Shape Name field, you will see the name SearchRectangleCollapsed. In the Widget Interactions and Notes pane, click in the Shape Name field and rename the widget SearchRectangleExpanded. In the toolbar, change x to 0 and w to 170. Click on the text field widget labeled SearchTextFieldCollapsed at coordinates (80,0) to select it and perform the following steps: In the Widget Interactions and Notes pane, click in the Text Field Name field and rename the widget SearchTextFieldExpanded. In the toolbar, change x to 0 and w to 145. With the search text field dynamic panel created, we are now ready to define the interactions that will cause the search text field element to expand and collapse. To create this effect, perform the steps given in the following sections: In the Widget Manager pane, double-click on the Collapsed state to open it in the design area. In the design area, click on the text field widget named SearchTextFieldCollapsed at coordinates (80,0). With the text field widget selected in the Widget Interactions and Notes pane, click on the Interactions tab, then on More Events, and, finally, click on OnMouseEnter. A Case Editor dialog box will open. In the Case Editor dialog box, perform the steps given in the following section. Create the first action: Under Click to add actions, scroll to the Dynamic Panels drop-down menu and click on Set Panel State. Under Configure actions, click on the checkbox next to Set ExpandingSearchDP state. Change Select the State to Expanded. Change Animate In to slide left t: 250 ms. Create the second action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Move. Under Configure actions, click on the checkbox next to HeaderLinksDP. Change Move by x to -80. Create the third action: Under Click to add actions, scroll to the Miscellaneous drop-down menu and click on Wait. Under Configure actions, change Wait time: to 350 ms. Create the fourth action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Bring to Front/Back. Under Configure actions, click on the checkbox next to SearchTextFieldExpanded. Next to Order, click on the radio button next to Bring to Front. Create the fifth action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Focus. Under Configure actions, click on the checkbox next to SearchTextFieldExpanded. Click on OK. In the Widget Interactions and Notes pane, click on the Interactions tab and then click on Case 1. In the main menu, click on Edit and then click on Copy. In the design area, click on the rectangle widget named SearchRectangleCollapsed at coordinates (80,0) to select it. Recall that we must slow-double-click near coordinates (90,10) to select the SearchRectangleCollapsed since it is beneath the SearchTextFieldCollapsed widget. With the rectangle widget selected in the Widget Interactions and Notes pane, click on the Interactions tab, then click on More Events, and next to OnMouseEnter, click on the Paste button. The OnMouseEnter event with Case 1 will be shown as follows: In the Widget Manager pane, double-click on the Expanded state to open it in the design area. Click on the text field widget named SearchTextFieldExpanded near coordinates (0,0) to select it. With the text field widget selected in the Widget Interactions and Notes pane, click on the Interactions tab, then on More Events, and, finally, click on OnLostFocus. A Case Editor dialog box will open. In the Case Editor dialog box, perform the following steps: Create the condition. Click the Add Condition button. In the Condition Builder dialog box, in the outlined condition box perform the following steps: In the first dropdown, select cursor. In the second dropdown, select is not over. In the third dropdown, select area of widget. In the fourth text box dropdown, select SearchRectangle. Click OK. Create the first action: Under Click to add actions, scroll to the Dynamic Panels drop-down menu and click on Set Panel State. Under Configure actions, click on the checkbox next to Set ExpandingSearchDP state. Change Select the State to Collapsed. Change Animate In to slide right t: 200 ms. Create the second action: Under Click to add actions, scroll to the Miscellaneous drop-down menu and click on Wait. Under Configure actions, change Wait time: to 150 ms. Create the third action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Move. Under Configure actions, click on the checkbox next to HeaderLinksDP. Change Move by x: to 80. Create the fourth action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Set Text. Under Configure actions, click on the checkbox next to SearchTextFieldExpanded. Under Set text to, click on the first dropdown and select text on widget. Click on the second dropdown and select SearchTextFieldExpanded. Your case editor will look like this: Create the fifth action: Under Click to add actions, scroll to the Widgets drop-down menu and click on Bring to Front/Back. Under Configure actions, click on the checkbox next to HeaderLinksDP. Next to Order, click on the radio button next to Bring to Front. Click on OK. In the design area, click on the text field widget named SearchTextFieldExpanded to select it. Perform the following steps: Right-click on the SearchTextFieldExpanded widget and click on Assign Submit Button. In the Assign Submit Button dialog box, click on the checkbox next to SearchRectangleExpanded. Click on OK. In the design area, select the rectangle widget named SearchRectangleExpanded by slow-double-clicking near coordinates (10,10). With the Rectangle widget selected, go to the Widget Interactions and Notes pane, click on the Interactions tab, and click on Create Link…. In the Sitemap modal window, click on the Search page. We have now created an expandable search text field widget that retains the text typed into the widget when the dynamic panel changes states. With the design completed for our header, we need to convert these widgets into a header master that can be leveraged on each page of our design. To create a header master, open the Home page in the design area then navigate to Edit | Select All in the main menu. Right-click on any widget in the design area and click on Convert to Master. In the Convert to Master dialog box, type Header. For Drop Behavior, click on the radio button next to Lock to Master Location. Click on the Continue button. You will now see the header master appear in the Masters pane. With our header Master completed, next we will design an interactive carousel. Summary In this article, we focused on creating the home page. A home page should be intuitive; it should capture one's attention and encourage further engagement with the site. For the home page, we used the easily recognizable elements found on popular e-commerce sites. We created logo, links to navigate to different pages, and shopping cart. we also learned how to create an expanding search bar. Resources for Article: Further resources on this subject: Common design patterns and how to prototype them [Article] Axure RP 6 Prototyping Essentials: Advanced Interactions [Article] Viewing on Mobile Devices [Article]

In Part 1 of this series, we got everything in place for our Koa app using Jade and Mongel. In this post, we will cover Jade templates and how to use listing and viewing pages. Please note that this series requires that you use Node.js version 0.11+. Jade templates Rendering HTML is always an important part of any web application. Luckily, when using Node.js there are many great choices, and for this article we’ve chosen Jade. Keep in mind though that we will only touch on a tiny fraction of the Jade functionality. Let’s create our first Jade template. Create a file called create.jade and put in the following: create.jade doctype html html(lang='en') head title Create Page body h1 Create Page form(method='POST', action='/create') input(type='text', name='title', placeholder='Title') input(type='text', name='contents', placeholder='Contents') input(type='submit') For all the Jade questions you have that we won’t answer in this series, I refer you to the excellent official Jade website at http://jade-lang.com . If you add the following statement app.listen(3000); to the end of index.js, then you should be able to run the program from your terminal using the following command and by visiting http://localhost:3000 in your browser. $ node --harmony index.js The --harmony flag just tells the node program that we need support for generators in our program: Listing and viewing pages Now that we can create a page in our MongoDB database, it is time to actually list and view these pages. For this purpose we need to add another middleware to our index.js file after the first middleware: app.use(function* () { if (this.method != 'GET') { this.status = 405; this.body = 'Method Not Allowed'; return } … }); As you can probably already tell, this new middleware is very similar to the first one we added that handled the creation of pages. At first we make sure that the method of the request is GET, and if not, we respond appropriately and return the following: var params = this.path.split('/').slice(1); var id = params[0]; if (id.length == 0) { var pages = yield Page.find(); var html = jade.renderFile('list.jade', { pages: pages }); this.body = html; return } Then, we proceed to inspect the path attribute of the Koa context, looking for an ID that represents the page in the database. Remember how we redirected using the ID in the previous middleware. We inspect the path by splitting it into an array of strings separated by the forward slashes of a URL; this way the path /1234 becomes an array of ‘’ and ‘1234.’ Because the path starts with a forward slash, the first item in the array will always be the empty string, so we just discard that by default. Then we check the length of the ID parameter, and if it’s zero we know that there is in fact no ID in the path, and we should just look for the pages in the database and render our list.jade template with those pages made available to the template as the variable pages. Making data available in templates is also known as providing locals to the template. list.jade doctype html html(lang="en") head title Your Web Application body h1 Your Web Application ul - each page in pages li a(href='/#{page._id}')= page.title But if the length of id was not zero, we assume that it’s an id and we try to load that specific page from the database instead of all the pages, and we proceed to render our view.jade template with the: var page = yield Page.findById(id); var html = jade.renderFile('view.jade', page); this.body = html; view.jade doctype html html(lang="en") head title= title body h1= title p= contents That’s it You should now be able to run the app as previously described and create a page, list all of your pages, and view them. If you want to, you can continue and build a simple CMS system. Koa is very simple to use and doesn’t enforce a lot of functionality on you, allowing you to pick and choose between libraries that you need and want to use. There are many possibilities and that is one of Koa’s biggest strengths. Find even more Node.js content on our Node.js page. Featuring our latest titles and most popular tutorials, it's the perfect place to learn more about Node.js. About the author Christoffer Hallas is a software developer and entrepreneur from Copenhagen, Denmark. He is a computer polyglot and contributes to and maintains a number of open source projects. When not contemplating his next grand idea (which remains an idea), he enjoys music, sports, and design of all kinds. Christoffer can be found on GitHub as hallas and at Twitter as @hamderhallas.

This article by Vinith Menon, the author of Microsoft Hyper-V PowerShell Automation, delves into the basics of Hyper-V, right from installing Hyper-V to resizing virtual hard disks. The Hyper-V PowerShell module includes several significant features that extend its use, improve its usability, and allow you to control and manage your Hyper-V environment with more granular control. Various organizations have moved on from Hyper-V (V2) to Hyper-V (V3). In Hyper-V (V2), the Hyper-V management shell was not built-in and the PowerShell module had to be manually installed. In Hyper-V (V3), Microsoft has provided an exhaustive set of cmdlets that can be used to manage and automate all configuration activities of the Hyper-V environment. The cmdlets are executed across the network using Windows Remote Management. In this article, we will cover: The basics of setting up a Hyper-V environment using PowerShell The fundamental concepts of Hyper-V management with the Hyper-V management shell The updated features in Hyper-V (For more resources related to this topic, see here.) Here is a list of all the new features introduced in Hyper-V in Windows Server 2012 R2. We will be going in depth through the important changes that have come into the Hyper-V PowerShell module with the following features and functions: Shared virtual hard disk Resizing the live virtual hard disk Installing and configuring your Hyper-V environment Installing and configuring Hyper-V using PowerShell Before you proceed with the installation and configuration of Hyper-V, there are some prerequisites that need to be taken care of: The user account that is used to install the Hyper-V role should have administrative privileges on the computer There should be enough RAM on the server to run newly created virtual machines Once the prerequisites have been taken care of, let's start with installing the Hyper-V role: Open a PowerShell prompt in Run as Administrator mode: Type the following into the PowerShell prompt to install the Hyper-V role along with the management tools; once the installation is complete, the Hyper-V Server will reboot and the Hyper-V role will be successfully installed: Install-WindowsFeature –Name Hyper-V -IncludeManagementTools - Restart Once the server boots up, verify the installation of Hyper-V using the Get-WindowsFeature cmdlet: Get-WindowsFeature -Name hyper* You will be able to see that the Hyper-V role, Hyper-V PowerShell management shell, and the GUI management tools are successfully installed:   Fundamental concepts of Hyper-V management with the Hyper-V management shell In this section, we will look at some of the fundamental concepts of Hyper-V management with the Hyper-V management shell. Once you get the Hyper-V role installed as per the steps illustrated in the previous section, a PowerShell module to manage your Hyper-V environment will also get installed. Now, perform the following steps: Open a PowerShell prompt in the Run as Administrator mode. PowerShell uses cmdlets that are built using a verb-noun naming system (for more details, refer to Learning Windows PowerShell Names at http://technet.microsoft.com/en-us/library/dd315315.aspx). Type the following command into the PowerShell prompt to get a list of all the cmdlets in the Hyper-V PowerShell module: Get-Command -Module Hyper-V Hyper-V in Windows Server 2012 R2 ships with about 178 cmdlets. These cmdlets allow a Hyper-V administrator to handle very simple, basic tasks to advanced ones such as setting up a Hyper-V replica for virtual machine disaster recovery. To get the count of all the available Hyper-V cmdlets, you can type the following command in PowerShell: Get-Command -Module Hyper-V | Measure-Object The Hyper-V PowerShell cmdlets follow a very simple approach and are very user friendly. The cmdlet name itself indirectly communicates with the Hyper-V administrator about its functionality. The following screenshot shows the output of the Get command: For example, in the following screenshot, the Remove-VMSwitch cmdlet itself says that it's used to delete a previously created virtual machine switch: If the administrator is still not sure about the task that can be performed by the cmdlet, he or she can get help with detailed examples using the Get-Help cmdlet. To get help on the cmdlet type, type the cmdlet name in the prescribed format. To make sure that the latest version of help files are installed on the server, run the Update-Help cmdlet before executing the following cmdlet: Get-Help <Hyper-V cmdlet> -Full The following screenshot is an example of the Get-Help cmdlet: Shared virtual hard disks This new and improved feature in Windows Server 2012 R2 allows an administrator to share a virtual hard disk file (the .vhdx file format) between multiple virtual machines. These .vhdx files can be used as shared storage for a failover cluster created between virtual machines (also known as guest clustering). A shared virtual hard disk allows you to create data disks and witness disks using .vhdx files with some advantages: Shared disks are ideal for SQL database files and file servers Shared disks can be run on generation 1 and generation 2 virtual machines This new feature allows you to save on storage costs and use the .vhdx files for guest clustering, enabling easier deployment rather than using virtual Fibre Channel or Internet Small Computer System Interface (iSCSI), which are complicated and require storage configuration changes such as zoning and Logic Unit Number (LUN) masking. In Windows Server 2012 R2, virtual iSCSI disks (both shared and unshared virtual hard disk files) show up as virtual SAS disks when you add an iSCSI hard disk to a virtual machine. Shared virtual hard disks (.vhdx) files can be placed on Cluster Shared Volumes (CSV) or a Scale-Out File Server cluster Let's look at the ways you can automate and manage your shared .vhdx guest clustering configuration using PowerShell. In the following example, we will demonstrate how you can create a two-node file server cluster using the shared VHDX feature. After that, let's set up a testing environment within which we can start learning these new features. The steps are as follows: We will start by creating two virtual machines each with 50 GB OS drives, which contains a sysprep image of Windows Server 2012 R2. Each virtual machine will have 4 GB RAM and four virtual CPUs. D:vhdbase_1.vhdx and D:vhdbase_2.vhdx are already existing VHDX files with sysprepped image of Windows Server 2012 R2. The following code is used to create two virtual machines: New-VM –Name "Fileserver_VM1" –MemoryStartupBytes 4GB – NewVHDPath d:vhdbase_1.vhdx -NewVHDSizeBytes 50GB New-VM –Name "Fileserver_VM2" –MemoryStartupBytes 4GB –NewVHDPath d:vhdbase_2.vhdx -NewVHDSizeBytes 50GB Next, we will install the file server role and configure a failover cluster on both the virtual machines using PowerShell. You need to enable PowerShell remoting on both the file servers and also have them joined to a domain. The following is the code: Install-WindowsFeature -computername Fileserver_VM1 File- Services, FS-FileServer, Failover-Clustering   Install-WindowsFeature -computername Fileserver_VM1 RSAT- Clustering –IncludeAllSubFeature   Install-WindowsFeature -computername Fileserver_VM2 File- Services, FS-FileServer, Failover-Clustering   Install-WindowsFeature -computername Fileserver_VM2 RSAT- Clustering -IncludeAllSubFeature Once we have the virtual machines created and the file server and failover clustering features installed, we will create the failover cluster as per Microsoft's best practices using the following set of cmdlets: New-Cluster -Name Cluster1 -Node FileServer_VM1,   FileServer_VM2 -StaticAddress 10.0.0.59 -NoStorage – Verbose You will need to choose a name and IP address that fits your organization. Next, we will create two vhdx files named sharedvhdx_data.vhdx (which will be used as a data disk) and sharedvhdx_quorum.vhdx (which will be used as the quorum or the witness disk). To do this, the following commands need to be run on the Hyper-V cluster: New-VHD -Path   c:ClusterStorageVolume1sharedvhdx_data.VHDX -Fixed - SizeBytes 10GB   New-VHD -Path   c:ClusterStorageVolume1sharedvhdx_quorum.VHDX -Fixed - SizeBytes 1GB Once we have created these virtual hard disk files, we will add them as shared .vhdx files. We will attach these newly created VHDX files to the Fileserver_VM1 and Fileserver_VM2 virtual machines and specify the parameter-shared VHDX files for guest clustering: Add-VMHardDiskDrive –VMName Fileserver_VM1 -Path   c:ClusterStorageVolume1sharedvhdx_data.VHDX – ShareVirtualDisk   Add-VMHardDiskDrive –VMName Fileserver_VM2 -Path   c:ClusterStorageVolume1sharedvhdx_data.VHDX – ShareVirtualDisk Finally, we will be making the disks available online and adding them to the failover cluster using the following command: Get-ClusterAvailableDisk | Add-ClusterDisk Once we have executed the preceding set of steps, we will have a highly available file server infrastructure using shared VHD files. Live virtual hard disk resizing With Windows Server 2012 R2, a newly added feature in Hyper-V allows the administrators to expand or shrink the size of a virtual hard disk attached to the SCSI controller while the virtual machines are still running. Hyper-V administrators can now perform maintenance operations on a live VHD and avoid any downtime by not temporarily shutting down the virtual machine for these maintenance activities. Prior to Windows Server 2012 R2, to resize a VHD attached to the virtual machine, it had to be turned off leading to costly downtime. Using the GUI controls, the VHD resize can be done by using only the Edit Virtual Hard Disk wizard. Also, note that the VHDs that were previously expanded can be shrunk. The Windows PowerShell way of doing a VHD resize is by using the Resize-VirtualDisk cmdlet. Let's look at the ways you can automate a VHD resize using PowerShell. In the next example, we will demonstrate how you can expand and shrink a virtual hard disk connected to a VM's SCSI controller. We will continue using the virtual machine that we created for our previous example. We have a pre-created VHD of 50 GB that is connected to the virtual machine's SCSI controller. Expanding the virtual hard disk Let's resize the aforementioned virtual hard disk to 57 GB using the Resize-Virtualdisk cmdlet: Resize-VirtualDisk -Name "scsidisk" -Size (57GB) Next, if we open the VM settings and perform an inspect disk operation, we'll be able to see that the VHDX file size has become 57 GB: Also, one can verify this when he or she logs into the VM, opens disk management, and extends the unused partition. You can see that the disk size has increased to 57 GB: Resizing the virtual hard disk Let's resize the earlier mentioned VHD to 57 GB using the Resize-Virtualdisk cmdlet: For this exercise, the primary requirement is to shrink the disk partition by logging in to the VM using disk management, as you can see in the following screenshot; we're shrinking the VHDX file by 7 GB: Next, click on Shrink. Once you complete this step, you will see that the unallocated space is 7 GB. You can also execute this step using the Resize-Partition Powershell cmdlet: Get-Partition -DiskNumber 1 | Resize-Partition -Size 50GB The following screenshot shows the partition: Next, we will resize/shrink the VHD to 50 GB: Resize-VirtualDisk -Name "scsidisk" -Size (50GB) Once the previous steps have been executed successfully, run a re-scan disk using disk management and you will see that the disk size is 50 GB: Summary In this article, we went through the basics of setting up a Hyper-V environment using PowerShell. We also explored the fundamental concepts of Hyper-V management with Hyper-V management shell. Resources for Article: Further resources on this subject: Hyper-V building blocks for creating your Microsoft virtualization platform [article] The importance of Hyper-V Security [article] Network Access Control Lists [article]

In this article by Paul Gerrard and Radia M. Johnson, the authors of Mastering Scientific Computation with R, we'll discuss the fundamental ideas underlying structural equation modeling, which are often overlooked in other books discussing structural equation modeling (SEM) in R, and then delve into how SEM is done in R. We will then discuss two R packages, OpenMx and lavaan. We can directly apply our discussion of the linear algebra underlying SEM using OpenMx. Because of this, we will go over OpenMx first. We will then discuss lavaan, which is probably more user friendly because it sweeps the matrices and linear algebra representations under the rug so that they are invisible unless the user really goes looking for them. Both packages continue to be developed and there will always be some features better supported in one of these packages than in the other. (For more resources related to this topic, see here.) SEM model fitting and estimation methods To ultimately find a good solution, software has to use trial and error to come up with an implied covariance matrix that matches the observed covariance matrix as well as possible. The question is what does "as well as possible" mean? The answer to this is that the software must try to minimize some particular criterion, usually some sort of discrepancy function. Just what that criterion is depends on the estimation method used. The most commonly used estimation methods in SEM include: Ordinary least squares (OLS) also called unweighted least squares Generalized least squares (GLS) Maximum likelihood (ML) There are a number of other estimation methods as well, some of which can be done in R, but here we will stick with describing the most common ones. In general, OLS is the simplest and computationally cheapest estimation method. GLS is computationally more demanding, and ML is computationally more intensive. We will see why this is, as we discuss the details of these estimation methods. Any SEM estimation method seeks to estimate model parameters that recreate the observed covariance matrix as well as possible. To evaluate how closely an implied covariance matrix matches an observed covariance matrix, we need a discrepancy function. If we assume multivariate normality of the observed variables, the following function can be used to assess discrepancy: In the preceding figure, R is the observed covariance matrix, C is the implied covariance matrix, and V is a weight matrix. The tr function refers to the trace function, which sums the elements of the main diagonal. The choice of V varies based on the SEM estimation method: For OLS, V = I For GLS, V = R-1 In the case of an ML estimation, we seek to minimize one of a number of similar criteria to describe ML, as follows: In the preceding figure, n is the number of variables. There are a couple of points worth noting here. GLS estimation inverts the observed correlation matrix, something computationally demanding with large matrices, but something that must only be done once. Alternatively, ML requires inversion of the implied covariance matrix, which changes with each iteration. Thus, each iteration requires the computationally demanding step of matrix inversion. With modern fast computers, this difference may not be noticeable, but with large SEM models, this might start to be quite time-consuming. Assessing SEM model fit The final question in an SEM model is how well the model explains the data. This is answered with the use of SEM measures of fit. Most of these measures are based on a chi-squared distribution. The fit criteria for GLS and ML (as well as a number of other estimation procedures such as asymptotic distribution-free methods) multiplied by N-1 is approximately chi-square distributed. Here, the capital N represents the number of observations in the dataset, as opposed to lower case n, which gives the number of variables. We compute degrees of freedom as the difference between the number of estimated parameters and the number of known covariances (that is, the total number of values in one triangle of an observed covariance matrix). This gives way to the first test statistic for SEM models, a chi-squared significance level comparing our chi-square value to some minimum chi-square threshold to achieve statistical significance. As with conventional chi-square testing, a chi-square value that is higher than some minimal threshold will reject the null hypothesis. Most experimental science features such as rejection supports the hypothesis of the experiment. This is not the case in SEM, where the null hypothesis is that the model fits the data. Thus, a non-significant chi-square is an indicator of model fit, whereas a significant chi-square rejects model fit. A notable limitation of this is that a greater sample size, greater N, will increase the chi-square value and will therefore increase the power to reject model fit. Thus, using conventional chi-squared testing will tend to support models developed in small samples and reject models developed in large samples. The choice an interpretation of fit measures is a contentious one in SEM literature. However, as can be seen, chi-square has limitations. As such, other model fit criteria were developed that do not penalize models that fit in large samples (some may penalize models fit to small samples though). There are over a dozen indices, but the most common fit indices and interpretation information are as follows: Comparative fit index: In this index, a higher value is better. Conventionally, a value of greater than 0.9 was considered an indicator of good model fit, but some might argue that a value of at least 0.95 is needed. This is relatively sample size insensitive. Root mean square error of approximation: A value of under 0.08 (smaller is better) is often considered necessary to achieve model fit. However, this fit measure is quite sample size sensitive, penalizing small sample studies. Tucker-Lewis index (Non-normed fit index): This is interpreted in a similar manner as the comparative fit index. Also, this is not very sample size sensitive. Standardized root mean square residual: In this index, a lower value is better. A value of 0.06 or less is considered needed for model fit. Also, this may penalize small samples. In the next section, we will show you how to actually fit SEM models in R and how to evaluate fit using fit measures. Using OpenMx and matrix specification of an SEM We went through the basic principles of SEM and discussed the basic computational approach by which this can be achieved. SEM remains an active area of research (with an entire journal devoted to it, Structural Equation Modeling), so there are many additional peculiarities, but rather than delving into all of them, we will start by delving into actually fitting an SEM model in R. OpenMx is not in the CRAN repository, but it is easily obtainable from the OpenMx website, by typing the following in R: source('http://openmx.psyc.virginia.edu/getOpenMx.R')" Summarizing the OpenMx approach In this example, we will use OpenMx by specifying matrices as mentioned earlier. To fit an OpenMx model, we need to first specify the model and then tell the software to attempt to fit the model. Model specification involves four components: Specifying the model matrices; this has two parts: Declare starting values for the estimation Declaring which values can be estimated and which are fixed Telling OpenMx the algebraic relationship of the matrices that should produce an implied covariance matrix Giving an instruction for the model fitting criterion Providing a source of data The R commands that correspond to each of these steps are: mxMatrix mxAlgebra mxMLObjective mxData We will then pass the objects created with each of these commands to create an SEM model using mxModel. Explaining an entire example First, to make things simple, we will store the FALSE and TRUE logical values in single letter variables, which will be convenient when we have matrices full of TRUE and FALSE values as follows: F <- FALSE T <- TRUE Specifying the model matrices Specifying matrices is done with the mxMatrix function, which returns an MxMatrix object. (Note that the object starts with a capital "M" while the function starts with a lowercase "m.") Specifying an MxMatrix is much like specifying a regular R matrix, but MxMatrices has some additional components. The most notable difference is that there are actually two different matrices used to create an MxMatrix. The first is a matrix of starting values, and the second is a matrix that tells which starting values are free to be estimated and which are not. If a starting value is not freely estimable, then it is a fixed constant. Since the actual starting values that we choose do not really matter too much in this case, we will just pick one as a starting value for all parameters that we would like to be estimated. Let's take a look at the following example: mx.A <- mxMatrix( type = "Full", nrow=14, ncol=14, #Provide the Starting Values values = c(    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0 ), #Tell R which values are free to be estimated    free = c(    F, F, F, F, F, F, F, F, F, F, F, F, F, F,    F, F, F, F, F, F, F, F, F, F, F, F, T, F,    F, F, F, F, F, F, F, F, F, F, F, F, T, F,    F, F, F, F, F, F, F, F, F, F, F, F, T, F,    F, F, F, F, F, F, F, F, F, F, F, F, F, F,    F, F, F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, F, F,    F, F, F, F, F, F, F, F, F, F, F, T, F, F,    F, F, F, F, F, F, F, F, F, F, F, T, F, F,    F, F, F, F, F, F, F, F, F, F, F, F, F, F,    F, F, F, F, F, F, F, F, F, F, F, T, F, F,    F, F, F, F, F, F, F, F, F, F, F, T, T, F ), byrow=TRUE,   #Provide a matrix name that will be used in model fitting name="A", ) We will now apply this same technique to the S matrix. Here, we will create two S matrices, S1 and S2. They differ simply in the starting values that they supply. We will later try to fit an SEM model using one matrix, and then the other to address problems with the first one. The difference is that S1 uses starting variances of 1 in the diagonal, and S2 uses starting variances of 5. Here, we will use the "symm" matrix type, which is a symmetric matrix. We could use the "full" matrix type, but by using "symm", we are saved from typing all of the symmetric values in the upper half of the matrix. Let's take a look at the following matrix: mx.S1 <- mxMatrix("Symm", nrow=14, ncol=14, values = c(    1,    0, 1,    0, 0, 1,    0, 1, 0, 1,    1, 0, 0, 0, 1,    0, 1, 0, 0, 0, 1,    0, 0, 1, 0, 0, 0, 1,    0, 0, 0, 1, 0, 1, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 ),      free = c(    T,    F, T,    F, F, T,    F, T, F, T,    T, F, F, F, T,    F, T, F, F, F, T,    F, F, T, F, F, F, T,    F, F, F, T, F, T, F, T,    F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, F, T ), byrow=TRUE, name="S" )   #The alternative, S2 matrix: mx.S2 <- mxMatrix("Symm", nrow=14, ncol=14, values = c(    5,    0, 5,    0, 0, 5,    0, 1, 0, 5,    1, 0, 0, 0, 5,    0, 1, 0, 0, 0, 5,    0, 0, 1, 0, 0, 0, 5,    0, 0, 0, 1, 0, 1, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5 ),         free = c(    T,    F, T,    F, F, T,    F, T, F, T,    T, F, F, F, T,    F, T, F, F, F, T,    F, F, T, F, F, F, T,    F, F, F, T, F, T, F, T,    F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, T,    F, F, F, F, F, F, F, F, F, F, F, F, F, T ), byrow=TRUE, name="S" ) mx.Filter <- mxMatrix("Full", nrow=11, ncol=14, values= c(        1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,      0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0    ),    free=FALSE,    name="Filter",    byrow = TRUE ) And finally, we will create our identity and filter matrices the same way, as follows: mx.I <- mxMatrix("Full", nrow=14, ncol=14,    values= c(        1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0,        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1    ),    free=FALSE,    byrow = TRUE,    name="I" ) Fitting the model Now, it is time to declare the model that we would like to fit using the mxModel command. This part includes steps 2 through step 4 mentioned earlier. Here, we will tell mxModel which matrices to use. We will then use the mxAlgegra command to tell R how the matrices should be combined to reproduce the implied covariance matrix. We will tell R to use ML estimation with the mxMLObjective command, and we will tell it to apply the estimation to a particular matrix algebra, which we named "C". This is simply the right-hand side of the McArdle McDonald equation. Finally, we will tell R where to get the data to use in model fitting using the following code: factorModel.1 <- mxModel("Political Democracy Model", #Model Matrices mx.A, mx.S1, mx.Filter, mx.I, #Model Fitting Instructions mxAlgebra(Filter %*% solve(I-A) %*% S %*% t(solve(I - A)) %*% t(Filter), name="C"),      mxMLObjective("C", dimnames = names(PoliticalDemocracy)),    #Data to fit mxData(cov(PoliticalDemocracy), type="cov", numObs=75) ) Now, let's tell R to fit the model and summarize the results using mxRun, as follows: summary(mxRun(factorModel.1)) Running Political Democracy Model Error in summary(mxRun(factorModel.1)) : error in evaluating the argument 'object' in selecting a method for function 'summary': Error: The job for model 'Political Democracy Model' exited abnormally with the error message: Expected covariance matrix is non-positive-definite. Uh oh! We got an error message telling us that the expected covariance matrix is not positive definite. Our observed covariance matrix is positive definite but the implied covariance matrix (at least at first) is not. This is an effect of the fact that if we multiply our starting value matrices together as specified by the McArdle McDonald equation, we get a starting implied covariance matrix. If we perform an eigenvalue decomposition of this starting implied covariance matrix, then we will find that the last eigenvalue is negative. This means a negative variance does not make much sense, and this is what "not positive definite" refers to. The good news is that this is simply our starting values, so we can fix this if we modify our starting values. In this case, we can choose values of five along the diagonal of the S matrix, and get a positive definite starting implied covariance matrix. We can rerun this using the mx.S2 matrix specified earlier and the software will proceed as follows: #Rerun with a positive definite matrix   factorModel.2 <- mxModel("Political Democracy Model", #Model Matrices mx.A, mx.S2, mx.Filter, mx.I, #Model Fitting Instructions mxAlgebra(Filter %*% solve(I-A) %*% S %*% t(solve(I - A)) %*% t(Filter), name="C"),    mxMLObjective("C", dimnames = names(PoliticalDemocracy)),    #Data to fit mxData(cov(PoliticalDemocracy), type="cov", numObs=75) )   summary(mxRun(factorModel.2)) This should provide a solution. As can be seen from the previous code, the parameters solved in the model are returned as matrix components. Just like we had to figure out how to go from paths to matrices, we now have to figure out how to go from matrices to paths (the reverse problem). In the following screenshot, we show just the first few free parameters: The preceding screenshot tells us that the parameter estimated in the position of the tenth row and twelfth column in the matrix A is 2.18. This corresponds to a path from the twelfth variable in the A matrix ind60, to the 10th variable in the matrix x2. Thus, the path coefficient from ind60 to x2 is 2.18. There are a few other pieces of information here. The first one tells us that the model has not converged but is "Mx status Green." This means that the model was still converging when it stopped running (that is, it did not converge), but an optimal solution was still found and therefore, the results are likely reliable. Model fit information is also provided suggesting a pretty good model fit with CFI of 0.99 and RMSEA of 0.032. This was a fair amount of work, and creating model matrices by hand from path diagrams can be quite tedious. For this reason, SEM fitting programs have generally adopted the ability to fit SEM by declaring paths rather than model matrices. OpenMx has the ability to allow declaration by paths, but applying model matrices has a few advantages. Principally, we get under the hood of SEM fitting. If we step back, we can see that OpenMx actually did very little for us that is specific to SEM. We told OpenMx how we wanted matrices multiplied together and which parameters of the matrix were free to be estimated. Instead of using the RAM specification, we could have passed the matrices of the LISREL or Bentler-Weeks models with the corresponding algebra methods to recreate an implied covariance matrix. This means that if we are trying to come up with our matrix specification, reproduce prior research, or apply a new SEM matrix specification method published in the literature, OpenMx gives us the power to do it. Also, for educators wishing to teach the underlying mathematical ideas of SEM, OpenMx is a very powerful tool. Fitting SEM models using lavaan If we were to describe OpenMx as the SEM equivalent of having a well-stocked pantry and full kitchen to create whatever you want, and you have the time and know how to do it, we might regard lavaan as a large freezer full of prepackaged microwavable dinners. It does not allow quite as much flexibility as OpenMx because it sweeps much of the work that we did by hand in OpenMx under the rug. Lavaan does use an internal matrix representation, but the user never has to see it. It is this sweeping under the rug that makes lavaan generally much easier to use. It is worth adding that the list of prepackaged features that are built into lavaan with minimal additional programming challenge many commercial SEM packages. The lavaan syntax The key to describing lavaan models is the model syntax, as follows: X =~ Y: Y is a manifestation of the latent variable X Y ~ X: Y is regressed on X Y ~~ X: The covariance between Y and X can be estimated Y ~ 1: This estimates the intercept for Y (implicitly requires mean structure) Y | a*t1 + b*t2: Y has two thresholds that is a and b Y ~ a * X: Y is regressed on X with coefficient a Y ~ start(a) * X: Y is regressed on X; the starting value used for estimation is a It may not be evident at first, but this model description language actually makes lavaan quite powerful. Wherever you have seen a or b in the previous examples, a variable or constant can be used in their place. The beauty of this is that multiple parameters can be constrained to be equal simply by assigning a single parameter name to them. Using lavaan, we can fit a factor analysis model to our physical functioning dataset with only a few lines of code: phys.func.data <- read.csv('phys_func.csv')[-1] names(phys.func.data) <- LETTERS[1:20] R has a built-in vector named LETTERS, which contains all of the capital letters of the English alphabet. The lower case vector letters contains the lowercase alphabet. We will then describe our model using the lavaan syntax. Here, we have a model of three latent variables, our factors, and each of them has manifest variables. Let's take a look at the following example: model.definition.1 <- ' #Factors    Cognitive =~ A + Q + R + S    Legs =~ B + C + D + H + I + J + M + N    Arms =~ E + F+ G + K +L + O + P + T    #Correlations Between Factors    Cognitive ~~ Legs    Cognitive ~~ Arms    Legs ~~ Arms ' We then tell lavaan to fit the model as follows: fit.phys.func <- cfa(model.definition.1, data=phys.func.data, ordered= c('A','B', 'C','D', 'E','F','G', 'H','I','J', 'K', 'L','M','N','O','P','Q','R', 'S', 'T')) In the previous code, we add an ordered = argument, which tells lavaan that some variables are ordinal in nature. In response, lavaan estimates polychoric correlations for these variables. Polychoric correlations assume that we binned a continuous variable into discrete categories, and attempts to explicitly model correlations assuming that there is some continuous underlying variable. Part of this requires finding thresholds (placed on an arbitrary scale) between each categorical response. (for example, threshold 1 falls between the response of 1 and 2, and so on). By telling lavaan to treat some variables as categorical, lavaan will also know to use a special estimation method. Lavaan will use diagonally weighted least squares, which does not assume normality and uses the diagonals of the polychoric correlation matrix for weights in the discrepancy function. With five response options, it is questionable as to whether polychoric correlations are truly needed. Some analysts might argue that with many response options, the data can be treated as continuous, but here we use this method to show off lavaan's capabilities. All SEM models in lavaan use the lavaan command. Here, we use the cfa command, which is one of a number of wrapper functions for the lavaan command. Others include sem and growth. These commands differ in the default options passed to the lavaan command. (For full details, see the package documentation.) Summarizing the data, we can see the loadings of each item on the factor as well as the factor intercorrelations. We can also see the thresholds between each category from the polychoric correlations as follows: summary(fit.phys.func) We can also assess things such as model fit using the fitMeasures command, which has most of the popularly used fit measures and even a few obscure ones. Here, we tell lavaan to simply extract three measures of model fit as follows: fitMeasures(fit.phys.func, c('rmsea', 'cfi', 'srmr')) Collectively, these measures suggest adequate model fit. It is worth noting here that the interpretation of fit measures largely comes from studies using maximum likelihood estimation, and there is some debate as to how well these generalize other fitting methods. The lavaan package also has the capability to use other estimators that treat the data as truly continuous in nature. For this, a particular dataset is far from multivariate normal distributed, so an estimator such as ML is appropriate to use. However, if we wanted to do so, the syntax would be as follows: fit.phys.func.ML <- cfa(model.definition.1, data=phys.func.data, estimator = 'ML') Comparing OpenMx to lavaan It can be seen that lavaan has a much simpler syntax that allows to rapidly model basic SEM models. However, we were a bit unfair to OpenMx because we used a path model specification for lavaan and a matrix specification for OpenMx. The truth is that OpenMx is still probably a bit wordier than lavaan, but let's apply a path model specification in each to do a fair head-to-head comparison. We will use the famous Holzinger-Swineford 1939 dataset here from the lavaan package to do our modeling, as follows: hs.dat <- HolzingerSwineford1939 We will create a new dataset with a shorter name so that we don't have to keep typing HozlingerSwineford1939. Explaining an example in lavaan We will learn to fit the Holzinger-Swineford model in this section. We will start by specifying the SEM model using the lavaan model syntax: hs.model.lavaan <- ' visual =~ x1 + x2 + x3 textual =~ x4 + x5 + x6 speed   =~ x7 + x8 + x9   visual ~~ textual visual ~~ speed textual ~~ speed '   fit.hs.lavaan <- cfa(hs.model.lavaan, data=hs.dat, std.lv = TRUE) summary(fit.hs.lavaan) Here, we add the std.lv argument to the fit function, which fixes the variance of the latent variables to 1. We do this instead of constraining the first factor loading on each variable to 1. Only the model coefficients are included for ease of viewing in this book. The result is shown in the following model: > summary(fit.hs.lavaan) …                      Estimate Std.err Z-value P(>|z|) Latent variables: visual =~    x1               0.900   0.081   11.127   0.000    x2               0.498   0.077   6.429   0.000    x3              0.656   0.074   8.817   0.000 textual =~    x4               0.990   0.057   17.474   0.000    x5               1.102   0.063   17.576   0.000    x6               0.917   0.054   17.082   0.000 speed =~    x7               0.619   0.070   8.903   0.000    x8               0.731   0.066   11.090   0.000    x9               0.670   0.065   10.305   0.000   Covariances: visual ~~    textual           0.459   0.064   7.189   0.000    speed             0.471   0.073   6.461   0.000 textual ~~    speed             0.283   0.069   4.117   0.000 Let's compare these results with a model fit in OpenMx using the same dataset and SEM model. Explaining an example in OpenMx The OpenMx syntax for path specification is substantially longer and more explicit. Let's take a look at the following model: hs.model.open.mx <- mxModel("Holzinger Swineford", type="RAM",      manifestVars = names(hs.dat)[7:15], latentVars = c('visual', 'textual', 'speed'),    # Create paths from latent to observed variables mxPath(        from = 'visual',        to = c('x1', 'x2', 'x3'),    free = c(TRUE, TRUE, TRUE),    values = 1          ), mxPath(        from = 'textual',        to = c('x4', 'x5', 'x6'),        free = c(TRUE, TRUE, TRUE),        values = 1      ), mxPath(    from = 'speed',    to = c('x7', 'x8', 'x9'),    free = c(TRUE, TRUE, TRUE),    values = 1      ), # Create covariances among latent variables mxPath(    from = 'visual',    to = 'textual',    arrows=2,    free=TRUE      ), mxPath(        from = 'visual',        to = 'speed',        arrows=2,        free=TRUE      ), mxPath(        from = 'textual',        to = 'speed',        arrows=2,        free=TRUE      ), #Create residual variance terms for the latent variables mxPath(    from= c('visual', 'textual', 'speed'),    arrows=2, #Here we are fixing the latent variances to 1 #These two lines are like st.lv = TRUE in lavaan    free=c(FALSE,FALSE,FALSE),    values=1 ), #Create residual variance terms mxPath( from= c('x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7', 'x8', 'x9'),    arrows=2, ),    mxData(        observed=cov(hs.dat[,c(7:15)]),        type="cov",        numObs=301    ) )     fit.hs.open.mx <- mxRun(hs.model.open.mx) summary(fit.hs.open.mx) Here are the results of the OpenMx model fit, which look very similar to lavaan's. This gives a long output. For ease of viewing, only the most relevant parts of the output are included in the following model (the last column that R prints giving the standard error of estimates is also not shown here): > summary(fit.hs.open.mx) …   free parameters:                            name matrix     row     col Estimate Std.Error 1   Holzinger Swineford.A[1,10]     A     x1 visual 0.9011177 2   Holzinger Swineford.A[2,10]     A     x2 visual 0.4987688 3   Holzinger Swineford.A[3,10]     A     x3 visual 0.6572487 4   Holzinger Swineford.A[4,11]     A     x4 textual 0.9913408 5   Holzinger Swineford.A[5,11]     A     x5 textual 1.1034381 6   Holzinger Swineford.A[6,11]     A     x6 textual 0.9181265 7   Holzinger Swineford.A[7,12]     A     x7   speed 0.6205055 8   Holzinger Swineford.A[8,12]     A     x8 speed 0.7321655 9   Holzinger Swineford.A[9,12]     A     x9   speed 0.6710954 10   Holzinger Swineford.S[1,1]     S     x1     x1 0.5508846 11   Holzinger Swineford.S[2,2]     S     x2     x2 1.1376195 12   Holzinger Swineford.S[3,3]     S    x3     x3 0.8471385 13   Holzinger Swineford.S[4,4]     S     x4     x4 0.3724102 14   Holzinger Swineford.S[5,5]     S     x5     x5 0.4477426 15   Holzinger Swineford.S[6,6]     S     x6     x6 0.3573899 16   Holzinger Swineford.S[7,7]      S     x7     x7 0.8020562 17   Holzinger Swineford.S[8,8]     S     x8     x8 0.4893230 18   Holzinger Swineford.S[9,9]     S     x9     x9 0.5680182 19 Holzinger Swineford.S[10,11]     S visual textual 0.4585093 20 Holzinger Swineford.S[10,12]     S visual   speed 0.4705348 21 Holzinger Swineford.S[11,12]     S textual   speed 0.2829848 In summary, the results agree quite closely. For example, looking at the coefficient for the path going from the latent variable visual to the observed variable x1, lavaan gives an estimate of 0.900 while OpenMx computes a value of 0.901. Summary The lavaan package is user friendly, pretty powerful, and constantly adding new features. Alternatively, OpenMx has a steeper learning curve but tremendous flexibility in what it can do. Thus, lavaan is a bit like a large freezer full of prepackaged microwavable dinners, whereas OpenMx is like a well-stocked pantry with no prepared foods but a full kitchen that will let you prepare it if you have the time and the know-how. To run a quick analysis, it is tough to beat the simplicity of lavaan, especially given its wide range of capabilities. For large complex models, OpenMx may be a better choice. The methods covered here are useful to analyze statistical relationships when one has all of the data from events that have already occurred. Resources for Article: Further resources on this subject: Creating your first heat map in R [article] Going Viral [article] Introduction to S4 Classes [article]

In this article by Matt Kaufman and Michael Wicherski, authors of the book Learning Apex Programming, we will see how we can use Apex to extend the Salesforce1 Platform. We will also see how to create a customized Force.com page. (For more resources related to this topic, see here.) Apex on its own is a powerful tool to extend the Salesforce1 Platform. It allows you to define your own database logic and fully customize the behavior of the platform. Sometimes, controlling "what happens behind the scenes isn't enough. You might have a complex process that needs to step users through a wizard or need to present data in a format that isn't native to the Salesforce1 Platform, or maybe even make things look like your corporate website. Anytime you need to go beyond custom logic and implement a custom interface, you can turn to Visualforce. Visualforce is the user interface framework for the Salesforce1 Platform. It supports the use of HTML, JavaScript, CSS, and Flash—all of which enable you to build your own custom web pages. These web pages are stored and hosted by the Salesforce1 Platform and can be exposed to just your internal users, your external community users, or publicly to the world. But wait, there's more! Also included with Visualforce is a robust markup language. This markup language (which is also referred to as Visualforce) allows you to bind your web pages to data and actions stored on the platform. It also allows you to leverage Apex for code-based objects and actions. Like the rest of the platform, the markup portion of Visualforce is upgraded three times a year with new tags and features. All of these features mean that Visualforce is very powerful. s-con-what? Before the "introduction of Visualforce, the Salesforce1 Platform had a feature called s-controls. These were simple files where you could write HTML, CSS, and JavaScript. There was no custom markup language included. In order to make things look like the Force.com GUI, a lot of HTML was required. If you wanted to create just a simple input form for a new Account record, so much HTML code was required. The following is just a" small, condensed excerpt of what the HTML would look like if you wanted to recreate such a screen from scratch: <div class="bPageTitle"><div class="ptBody"><div class="content"> <img src="/s.gif" class="pageTitleIcon" title="Account" /> <h1 class="pageType">    Account Edit<span class="titleSeparatingColon">:</span> </h1> <h2 class="pageDescription"> New Account</h2> <div class="blank">&nbsp;</div> </div> <div class="links"></div></div><div   class="ptBreadcrumb"></div></div> <form action="/001/e" method="post" onsubmit="if   (window.ffInAlert) { return false; }if (window.sfdcPage   &amp;&amp; window.sfdcPage.disableSaveButtons) { return   window.sfdcPage.disableSaveButtons(); }"> <div class="bPageBlock brandSecondaryBrd bEditBlock   secondaryPalette"> <div class="pbHeader">    <table border="0" cellpadding="0" cellspacing="0"><tbody>      <tr>      <td class="pbTitle">      <img src="/s.gif" width="12" height="1" class="minWidth"         style="margin-right: 0.25em;margin-right: 0.25em;margin-       right: 0.25em;">      <h2 class="mainTitle">Account Edit</h2>      </td>      <td class="pbButton" id="topButtonRow">      <input value="Save" class="btn" type="submit">      <input value="Cancel" class="btn" type="submit">      </td>      </tr>    </tbody></table> </div> <div class="pbBody">    <div class="pbSubheader brandTertiaryBgr first       tertiaryPalette" >    <span class="pbSubExtra"><span class="requiredLegend       brandTertiaryFgr"><span class="requiredExampleOuter"><span       class="requiredExample">&nbsp;</span></span>      <span class="requiredMark">*</span>      <span class="requiredText"> = Required Information</span>      </span></span>      <h3>Account Information<span         class="titleSeparatingColon">:</span> </h3>    </div>    <div class="pbSubsection">    <table class="detailList" border="0" cellpadding="0"     cellspacing="0"><tbody>      <tr>        <td class="labelCol requiredInput">        <label><span class="requiredMark">*</span>Account         Name</label>      </td>      <td class="dataCol col02">        <div class="requiredInput"><div         class="requiredBlock"></div>        <input id="acc2" name="acc2" size="20" type="text">        </div>      </td>      <td class="labelCol">        <label>Website</label>      </td>      <td class="dataCol">        <span>        <input id="acc12" name="acc12" size="20" type="text">        </span>      </td>      </tr>    </tbody></table>    </div> </div> <div class="pbBottomButtons">    <table border="0" cellpadding="0" cellspacing="0"><tbody>    <tr>      <td class="pbTitle"><img src="/s.gif" width="12" height="1"       class="minWidth" style="margin-right: 0.25em;margin-right:       0.25em;margin-right: 0.25em;">&nbsp;</td>      <td class="pbButtonb" id="bottomButtonRow">      <input value=" Save " class="btn" title="Save"         type="submit">      <input value="Cancel" class="btn" type="submit">      </td>    </tr>    </tbody></table> </div> <div class="pbFooter secondaryPalette"><div class="bg"> </div></div> </div> </form> We did our best to trim down this HTML to as little as possible. Despite all of our efforts, it still "took up more space than we wanted. The really sad part is that all of that code only results in the following screenshot: Not only was it time consuming to write all this HTML, but odds were that we wouldn't get it exactly right the first time. Worse still, every time the business requirements changed, we had to go through the exhausting effort of modifying the HTML code. Something had to change in order to provide us relief. That something was the introduction of Visualforce and its markup language. Your own personal Force.com The markup "tags in Visualforce correspond to various parts of the Force.com GUI. These tags allow you to quickly generate HTML markup without actually writing any HTML. It's really one of the greatest tricks of the Salesforce1 Platform. You can easily create your own custom screens that look just like the built-in ones with less effort than it would take you to create a web page for your corporate website. Take a look at the Visualforce markup that corresponds to the HTML and screenshot we showed you earlier: <apex:page standardController="Account" > <apex:sectionHeader title="Account Edit" subtitle="New Account"     /> <apex:form>    <apex:pageBlock title="Account Edit" mode="edit" >      <apex:pageBlockButtons>        <apex:commandButton value="Save" action="{!save}" />        <apex:commandButton value="Cancel" action="{!cancel}" />      </apex:pageBlockButtons>      <apex:pageBlockSection title="Account Information" >        <apex:inputField value="{!account.Name}" />        <apex:inputField value="{!account.Website}" />      </apex:pageBlockSection>    </apex:pageBlock> </apex:form> </apex:page> Impressive! With "merely these 15 lines of markup, we can render nearly 100 lines of earlier HTML. Don't believe us, you can try it out yourself. Creating a Visualforce page Just like" triggers and classes, Visualforce pages can "be created and edited using the Force.com IDE. The Force.com GUI also includes a web-based editor to work with Visualforce pages. To create a new Visualforce page, perform these simple steps: Right-click on your project and navigate to New | Visualforce Page. The Create New Visualforce Page window appears as shown: Enter" the label and name for your "new page in the Label and Name fields, respectively. For this example, use myTestPage. Select the API version for the page. For this example, keep it at the default value. Click on Finish. A progress bar will appear followed by your new Visualforce page. Remember that you always want to create your code in a Sandbox or Developer Edition org, not directly in Production. It is technically possible to edit Visualforce pages in Production, but you're breaking all sorts of best practices when you do. Similar to other markup languages, every tag in a Visualforce page must be closed. Tags and their corresponding closing tags must also occur in a proper order. The values of tag attributes are enclosed by double quotes; however, single quotes can be used inside the value to denote text values. Every Visualforce page starts with the <apex:page> tag and ends with </apex:page> as shown: <apex:page> <!-- Your content goes here --> </apex:page> Within "the <apex:page> tags, you can paste "your existing HTML as long as it is properly ordered and closed. The result will be a web page hosted by the Salesforce1 Platform. Not much to see here If you are" a web developer, then there's a lot you can "do with Visualforce pages. Using HTML, CSS, and images, you can create really pretty web pages that educate your users. If you have some programming skills, you can also use JavaScript in your pages to allow for interaction. If you have access to web services, you can use JavaScript to call the web services and make a really powerful application. Check out the following Visualforce page for an example of what you can do: <apex:page> <script type="text/javascript"> function doStuff(){    var x = document.getElementById("myId");    console.log(x); } </script> <img src="http://www.thisbook.com/logo.png" /> <h1>This is my title</h1> <h2>This is my subtitle</h2> <p>In a world where books are full of code, there was only one     that taught you everything you needed to know about Apex!</p> <ol>    <li>My first item</li>    <li>Etc.</li> </ol> <span id="myId"></span> <iframe src="http://www.thisbook.com/mypage.html" /> <form action="http://thisbook.com/submit.html" >    <input type="text" name="yoursecret" /> </form> </apex:page> All of this code is standalone and really has nothing to do with the Salesforce1 Platform other than being hosted by it. However, what really makes Visualforce powerful is its ability to interact with your data, which allows your pages to be more dynamic. Even better, you" can write Apex code to control how "your pages behave, so instead of relying on client-side JavaScript, your logic can run server side. Summary In this article we learned how a few features of Apex and how we can use it to extend the SalesForce1 Platform. We also created a custom Force.com page. Well, you've made a lot of progress. Not only can you write code to control how the database behaves, but you can create beautiful-looking pages too. You're an Apex rock star and nothing is going to hold you back. It's time to show your skills to the world. If you want to dig deeper, buy the book and read Learning Apex Programming in a simple step-by-step fashion by using Apex, the language for extension of the Salesforce1 Platform. Resources for Article: Further resources on this subject: Learning to Fly with Force.com [article] Building, Publishing, and Supporting Your Force.com Application [article] Adding a Geolocation Trigger to the Salesforce Account Object [article]

This article written by Raydelto Hernandez, the author of Cocos2d-x Android Game Development, explains the history of game development. It also shows how Cocos2d-x is a beneficial software for game development. This article also explains that this software is free and open source, which makes it all the more beneficial. The launch of the Apple App Store back in 2008 leveraged the reach capacity of indie game developers that since this occurrence are able to reach millions of users and compete with large companies, outperforming them in some situations. This reality led the trend of creating reusable game engines such as Cocos2D-iPhone written natively using Objective-C by the argentine, Ricardo Quesada; it allowed many independent developers to reach the top charts of downloads. Picking an existing game engine is a smart choice for indies and large companies since it allows them to focus on the game logic rather than rewriting core features over and over again, thus there are many game engines out there with all kind of licenses and characteristics. The most popular game engines for mobile systems right now are Unity, Marmalade, and Cocos2d-x; the three of them have the capabilities to create 2D and 3D games. Determining which one is the best in terms of ease of use and available tools may be arguably but, there is one objective fact that we can mention that could be easily verified. Among these three engines, Cocos2d-x is the only one that you can use for free, no matter how much money you make using it. We highlighted on this article's title that Cocos2d-x is completely free. This emphasis was done because the other two frameworks also allow some ways of free usage; nevertheless, both at some point require a payment for the usage license. In order to understand why Cocos2d-x is still free and open source, we need to understand how this tool was born. Ricardo, an enthusiastic Python programmer, often participated on game creation challenges from the scratch in only one week. Back in those days, Ricardo and his team re-wrote the core engine for each game until they came with the idea of creating a framework for encapsulating core game capabilities that could be used on any two-dimensional game and make it open source, so contributions could be received worldwide. And that is why Cocos2d was originally written for fun. With the launch in 2007 of the first iPhone, Ricardo lead the development of the port of the Cocos2d Python framework to the iPhone platform using its native language Objective-C. Cocos2D-iPhone quickly became popular among indie game developers, some of them turning themselves into appillionaires, as Chris Stevens called those individuals and enterprises that made millions of dollars during the app store bubble period. This phenomenon made game development companies look at this framework created by hobbyist as a tool creating their products. Zynga was one of the first big companies to adopt Cocos2d as their framework for delivering their famous Farmville game to the iPhone in 2009; this company trades on NASDAQ since 2011 and has more than 2,000 employees. In July 2010, a C++ port of the Cocos2d iPhone called Cocos2d-x was written in China with the objective of taking the power of the framework to other platforms such as the Android operating system that by that time was gaining market share at a spectacular rate. In 2011, this Cocos2d port was acquired by Chukong Technologies, the third largest mobile game development company in China, who later hired the original Cocos2d-iPhone author to join their team. Today, Cocos2d-x-based games dominate the top grossing charts of Google Play and the App Store, especially in Asia. Recognized companies and leading studios such as Konami, Zynga, BANDAI NAMCO, Wooga, Disney Mobile, and Square Enix are using Cocos2d-x in their games. Currently, there are 400,000 developers working on adding new functionalities and making this framework as stable as possible, including engineers from Google, ARM, INTEL, BlackBerry, and Microsoft, who officially support the ports to their products such as Windows Phone, Windows, Windows Metro Interface, and they're planning to support Cocos2d-x for the Xbox during this year. Cocos2d-x is a very straightforward engine that requires a little learning curve to grasp it. I teach game development courses at many universities using this framework. During the first week, the students are capable of creating a game with the complexity of the famous title, Doodle Jump. This can be easily achieved because the framework provides us with all the single components required for our game, such as physics, audio-handling, collision detection, animations, networking, data storage, user input, map rendering, scene transitions, 3D rendering, particle systems rendering, font handling, menu creation, displaying forms, threads handling, and so on, abstracting us from the low-level logic and allowing us to focus on the game logic. In conclusion, if you are willing to learn how to develop games for mobile platforms I strongly recommend you to learn and use the Cocos2d-x framework because it is easy to use, is totally free, is open source, which means that you could better understand it by reading its source, you could modify it if needed, and you have the warranty that you will never be forced to pay a license fee if your game becomes a hit. Another big advantage of this framework is its highly available documentation including the Packt Publishing collection of Cocos2d-x game development books. Sumary This article talked about the different uses of Cocos2d-x. It explained how Cocos2d-x is used worldwide today for game development. This article talked about the use of Cocos2d-x as a free and open source platform for game development.

In this article by Marco Schwartz and Oliver Manickum authors of the book Programming Arduino with LabVIEW, we will see how to design an interfave using LabVIEW. (For more resources related to this topic, see here.) At this stage, we know that we have our two sensors working and that they were interfaced correctly with the LabVIEW interface. However, we can do better; for now, we simply have a text display of the measurements, which is not elegant to read. Also, the light-level measurement goes from 0 to 5, which doesn't mean anything for somebody who will look at the interface for the first time. Therefore, we will modify the interface slightly. We will add a temperature gauge to display the data coming from the temperature sensor, and we will modify the output of the reading from the photocell to display the measurement from 0 (no light) to 100 percent (maximum brightness). We first need to place the different display elements. To do this, perform the following steps: Start with Front Panel. You can use a temperature gauge for the temperature and a simple slider indicator for Light Level. You will find both in the Indicators submenu of LabVIEW. After that, simply place them on the right-hand side of the interface and delete the other indicators we used earlier. Also, name the new indicators accordingly so that we can know to which element we have to connect them later. Then, it is time to go back to Block Diagram to connect the new elements we just added in Front Panel. For the temperature element, it is easy: you can simply connect the temperature gauge to the TMP36 output pin. For the light level, we will make slightly more complicated changes. We will divide the measured value beside the Analog Read element by 5, thus obtaining an output value between 0 and 1. Then, we will multiply this value by 100, to end up with a value going from 0 to 100 percent of the ambient light level. To do so perform the following steps: The first step is to place two elements corresponding to the two mathematical operations we want to do: a divide operator and a multiply operator. You can find both of them in the Functions panel of LabVIEW. Simply place them close to the Analog Read element in your program. After that, right-click on one of the inputs of each operator element, and go to Create | Constant to create a constant input for each block. Add a value of 5 for the division block, and add a value of 100 for the multiply block. Finally, connect the output of the Analog Read element to the input of the division block, the output of this block to the input of the multiply block, and the output of the multiply block to the input of the Light Level indicator. You can now go back to Front Panel to see the new interface in action. You can run the program again by clicking on the little arrow on the toolbar. You should immediately see that Temperature is now indicated by the gauge on the right and Light Level is immediately changing on the slider, depending on how you cover the sensor with your hand. Summary In this article, we connected a temperature sensor and a light-level sensor to Arduino and built a simple LabVIEW program to read data from these sensors. Then, we built a nice graphical interface to visualize the data coming from these sensors. There are many ways you can build other projects based on what you learned in this article. You can, for example, connect higher temperatures and/or more light-level sensors to the Arduino board and display these measurements in the interface. You can also connect other kinds of sensors that are supported by LabVIEW, for example, other analog sensors. For example, you can add a barometric pressure sensor or a humidity sensor to the project to build an even more complete weather-measurement station. One other interesting extension of this article will be to use the storage and plotting capabilities of LabVIEW to dynamically plot the history of the measured data inside the LabVIEW interface. Resources for Article: Further resources on this subject: The Arduino Mobile Robot [article] Using the Leap Motion Controller with Arduino [article] Avoiding Obstacles Using Sensors [article]

This article written by Belén Cruz Zapata, the author of the book Android Studio Essentials, teaches us the uses of the AVD Manager tool. It introduces us to the Google Play services. (For more resources related to this topic, see here.) The Android Virtual Device Manager (AVD Manager) is an Android tool accessible from Android Studio to manage the Android virtual devices that will be executed in the Android emulator. To open the AVD Manager from Android Studio, navigate to the Tools | Android | AVD Manager menu option. You can also click on the shortcut from the toolbar. The AVD Manager displays the list of the existing virtual devices. Since we have not created any virtual device, initially the list will be empty. To create our first virtual device, click on the Create Virtual Device button to open the configuration dialog. The first step is to select the hardware configuration of the virtual device. The hardware definitions are listed on the left side of the window. Select one of them, like the Nexus 5, to examine its details on the right side as shown in the following screenshot. Hardware definitions can be classified into one of these categories: Phone, Tablet, Wear or TV. We can also configure our own hardware device definitions from the AVD Manager. We can create a new definition using the New Hardware Profile button. The Clone Device button creates a duplicate of an existing device. Click on the New Hardware Profile button to examine the existing configuration parameters. The most important parameters that define a device are: Device Name: Name of the device. Screensize: Screen size in inches. This value determines the size category of the device. Type a value of 4.0 and notice how the Size value (on the right side) is normal. Now type a value of 7.0 and the Size field changes its value to large. This parameter along with the screen resolution also determines the density category. Resolution: Screen resolution in pixels. This value determines the density category of the device. Having a screen size of 4.0 inches, type a value of 768 x 1280 and notice how the density value is 400 dpi. Change the screen size to 6.0 inches and the density value changes to hdpi. Now change the resolution to 480 x 800 and the density value is mdpi. RAM: RAM memory size of the device. Input: Indicate if the home, back, or menu buttons of the device are available via software or hardware. Supported device states: Check the allowed states. Cameras: Select if the device has a front camera or a back camera. Sensors: Sensors available in the device: accelerometer, gyroscope, GPS, and proximity sensor. Default Skin: Select additional hardware controls. Create a new device with a screen size of 4.7 inches, a resolution of 800 x 1280, a RAM value of 500 MiB, software buttons, and both portrait and landscape states enabled. Name it as My Device. Click on the Finish button. The hardware definition has been added to the list of configurations. Click on the Next button to continue the creation of a new virtual device. The next step is to select the virtual device system image and the target Android platform. Each platform has its architecture, so the system images that are installed on your system will be listed along with the rest of the images that can be downloaded (Show downloadable system images box checked). Download and select one of the images of the Lollipop release and click on the Next button. Finally, the last step is to verify the configuration of the virtual device. Enter the name of the Android Virtual Device in the AVD Name field. Give the virtual device a meaningful name to recognize it easily, such as AVD_nexus5_api21. Click on the Show Advanced Settings button. The settings that we can configure for the virtual device are the following: Emulation Options: The Store a snapshot for faster startup option saves the state of the emulator in order to load faster the next time. The Use Host GPU tries to accelerate the GPU hardware to run the emulator faster. Custom skin definition: Select if additional hardware controls are displayed in the emulator. Memory and Storage: Select the memory parameters of the virtual device. Let the default values, unless a warning message is shown; in this case, follow the instructions of the message. For example, select 1536M for the RAM memory and 64 for the VM Heap. The Internal Storage can also be configured. Select for example: 200 MiB. Select the size of the SD Card or select a file to behave as the SD card. Device: Select one of the available device configurations. These configurations are the ones we tested in the layout editor preview. Select the Nexus 5 device to load its parameters in the dialog. Target: Select the device Android platform. We have to create one virtual device with the minimum platform supported by our application and another virtual device with the target platform of our application. For this first virtual device, select the target platform, Android 4.4.2 - API Level 19. CPU/ABI: Select the device architecture. The value of this field is set when we select the target platform. Each platform has its architecture, so if we do not have it installed, the following message will be shown; No system images installed for this target. To solve this, open the SDK Manager and search for one of the architectures of the target platform, ARM EABI v7a System Image or Intel x86 Atom System Image. Keyboard: Select if a hardware keyboard is displayed in the emulator. Check it. Skin: Select if additional hardware controls are displayed in the emulator. You can select the Skin with dynamic hardware controls option. Front Camera: Select if the emulator has a front camera or a back camera. The camera can be emulated or can be real by the use of a webcam from the computer. Select None for both cameras. Keyboard: Select if a hardware keyboard is displayed in the emulator. Check it. Network: Select the speed of the simulated network and select the delay in processing data across the network. The new virtual device is now listed in the AVD Manager. Select the recently created virtual device to enable the remaining actions: Start: Run the virtual device. Edit: Edit the virtual device configuration. Duplicate: Creates a new device configuration displaying the last step of the creation process. You can change its configuration parameters and then verify the new device. Wipe Data: Removes the user files from the virtual device. Show on Disk: Opens the virtual device directory on your system. View Details: Open a dialog detailing the virtual device characteristics. Delete: Delete the virtual device. Click on the Start button. The emulator will be opened as shown in the following screenshot. Wait until it is completely loaded, and then you will be able to try it. In Android Studio, open the main layout with the graphical editor and click on the list of the devices. As the following screenshot shows, our custom device definition appears and we can select it to preview the layout: Navigation Editor The Navigation Editor is a tool to create and structure the layouts of the application using a graphical viewer. To open this tool navigate to the Tools | Android | Navigation Editor menu. The tool opens a file in XML format named main.nvg.xml. This file is stored in your project at /.navigation/app/raw/. Since there is only one layout and one activity in our project, the navigation editor only shows this main layout. If you select the layout, detailed information about it is displayed on the right panel of the editor. If you double-click on the layout, the XML layout file will be opened in a new tab. We can create a new activity by right-mouse clicking on the editor and selecting the New Activity option. We can also add transitions from the controls of a layout by shift clicking on a control and then dragging to the target activity. Open the main layout and create a new button with the label Open Activity: <Button        android_id="@+id/button_open"        android_layout_width="wrap_content"        android_layout_height="wrap_content"        android_layout_below="@+id/button_accept"        android_layout_centerHorizontal="true"        android_text="Open Activity" /> Open the Navigation Editor and add a second activity. Now the navigation editor displays both activities as the next screenshot shows. Now we can add the navigation between them. Shift-drag from the new button of the main activity to the second activity. A blue line and a pink circle have been added to represent the new navigation. Select the navigation relationship to see its details on the right panel as shown in the following screenshot. The right panel shows the source the activity, the destination activity and the gesture that triggers the navigation. Now open our main activity class and notice the new code that has been added to implement the recently created navigation. The onCreate method now contains the following code: findViewById(R.id.button_open).setOnClickListener( new View.OnClickListener() { @Override public void onClick(View v) { MainActivity.this.startActivity( new Intent(MainActivity.this, Activity2.class)); } }); This code sets the onClick method of the new button, from where the second activity is launched. Summary This article thought us about the Navigation Editor tool. It also showed how to integrate the Google Play services with a project in Android Studio. In this article, we got acquainted to the AVD Manager tool. Resources for Article: Further resources on this subject: Android Native Application API [article] Creating User Interfaces [article] Android 3.0 Application Development: Multimedia Management [article]

In this article by Chitij Chauhan, author of the book PostgreSQL Cookbook, we will talk about various high availability and replication solutions, including some popular third-party replication tools such as Slony-I and Londiste. In this article, we will cover the following recipes: Setting up hot streaming replication Replication using Slony-I Replication using Londiste The important components for any production database is to achieve fault tolerance, 24/7 availability, and redundancy. It is for this purpose that we have different high availability and replication solutions available for PostgreSQL. From a business perspective, it is important to ensure 24/7 data availability in the event of a disaster situation or a database crash due to disk or hardware failure. In such situations, it becomes critical to ensure that a duplicate copy of the data is available on a different server or a different database, so that seamless failover can be achieved even when the primary server/database is unavailable. Setting up hot streaming replication In this recipe, we are going to set up a master-slave streaming replication. Getting ready For this exercise, you will need two Linux machines, each with the latest version of PostgreSQL installed. We will be using the following IP addresses for the master and slave servers: Master IP address: 192.168.0.4 Slave IP address: 192.168.0.5 Before you start with the master-slave streaming setup, it is important that the SSH connectivity between the master and slave is setup. How to do it... Perform the following sequence of steps to set up a master-slave streaming replication: First, we are going to create a user on the master, which will be used by the slave server to connect to the PostgreSQL database on the master server: psql -c "CREATE USER repuser REPLICATION LOGIN ENCRYPTED PASSWORD 'charlie';" Next, we will allow the replication user that was created in the previous step to allow access to the master PostgreSQL server. This is done by making the necessary changes as mentioned in the pg_hba.conf file: Vi pg_hba.conf host   replication   repuser   192.168.0.5/32   md5 In the next step, we are going to configure parameters in the postgresql.conf file. These parameters need to be set in order to get the streaming replication working: Vi /var/lib/pgsql/9.3/data/postgresql.conf listen_addresses = '*' wal_level = hot_standby max_wal_senders = 3 wal_keep_segments = 8 archive_mode = on       archive_command = 'cp %p /var/lib/pgsql/archive/%f && scp %p postgres@192.168.0.5:/var/lib/pgsql/archive/%f' checkpoint_segments = 8 Once the parameter changes have been made in the postgresql.conf file in the previous step, the next step will be to restart the PostgreSQL server on the master server, in order to let the changes take effect: pg_ctl -D /var/lib/pgsql/9.3/data restart Before the slave can replicate the master, we will need to give it the initial database to build off. For this purpose, we will make a base backup by copying the primary server's data directory to the standby. The rsync command needs to be run as a root user: psql -U postgres -h 192.168.0.4 -c "SELECT pg_start_backup('label', true)" rsync -a /var/lib/pgsql/9.3/data/ 192.168.0.5:/var/lib/pgsql/9.3/data/ --exclude postmaster.pid psql -U postgres -h 192.168.0.4 -c "SELECT pg_stop_backup()" Once the data directory, mentioned in the previous step, is populated, the next step is to enable the following parameter in the postgresql.conf file on the slave server: hot_standby = on The next step will be to copy the recovery.conf.sample file in the $PGDATA location on the slave server and then configure the following parameters: cp /usr/pgsql-9.3/share/recovery.conf.sample /var/lib/pgsql/9.3/data/recovery.conf standby_mode = on primary_conninfo = 'host=192.168.0.4 port=5432 user=repuser password=charlie' trigger_file = '/tmp/trigger.replication′ restore_command = 'cp /var/lib/pgsql/archive/%f "%p"' The next step will be to start the slave server: service postgresql-9.3 start Now that the above mentioned replication steps are set up, we will test for replication. On the master server, log in and issue the following SQL commands: psql -h 192.168.0.4 -d postgres -U postgres -W postgres=# create database test;   postgres=# c test;   test=# create table testtable ( testint int, testchar varchar(40) );   CREATE TABLE test=# insert into testtable values ( 1, 'What A Sight.' ); INSERT 0 1 On the slave server, we will now check whether the newly created database and the corresponding table, created in the previous step, are replicated: psql -h 192.168.0.5 -d test -U postgres -W test=# select * from testtable; testint | testchar ---------+--------------------------- 1 | What A Sight. (1 row) How it works... The following is the explanation for the steps performed in the preceding section. In the initial step of the preceding section, we create a user called repuser, which will be used by the slave server to make a connection to the primary server. In the second step of the preceding section, we make the necessary changes in the pg_hba.conf file to allow the master server to be accessed by the slave server using the repuser user ID that was created in step 1. We then make the necessary parameter changes on the master in step 3 of the preceding section to configure a streaming replication. The following is a description of these parameters: listen_addresses: This parameter is used to provide the IP address associated with the interface that you want to have PostgreSQL listen to. A value of * indicates all available IP addresses. wal_level: This parameter determines the level of WAL logging done. Specify hot_standby for streaming replication. wal_keep_segments: This parameter specifies the number of 16 MB WAL files to be retained in the pg_xlog directory. The rule of thumb is that more such files might be required to handle a large checkpoint. archive_mode: Setting this parameter enables completed WAL segments to be sent to the archive storage. archive_command: This parameter is basically a shell command that is executed whenever a WAL segment is completed. In our case, we are basically copying the file to the local machine and then using the secure copy command to send it across to the slave. max_wal_senders: This parameter specifies the total number of concurrent connections allowed from the slave servers. checkpoint_segments: This parameter specifies the maximum number of logfile segments between automatic WAL checkpoints. Once the necessary configuration changes have been made on the master server, we then restart the PostgreSQL server on the master in order to let the new configuration changes take effect. This is done in step 4 of the preceding section. In step 5 of the preceding section, we are basically building the slave by copying the primary server's data directory to the slave. Now, with the data directory available on the slave, the next step is to configure it. We will now make the necessary parameter replication related parameter changes on the slave in the postgresql.conf directory on the slave server. We set the following parameters on the slave: hot_standby: This parameter determines whether you can connect and run queries when the server is in the archive recovery or standby mode. In the next step, we are configuring the recovery.conf file. This is required to be set up so that the slave can start receiving logs from the master. The parameters explained next are configured in the recovery.conf file on the slave. standby_mode: This parameter, when enabled, causes PostgreSQL to work as a standby in a replication configuration. primary_conninfo: This parameter specifies the connection information used by the slave to connect to the master. For our scenario, our master server is set as 192.168.0.4 on port 5432 and we are using the repuser userid with the password charlie to make a connection to the master. Remember that repuser was the userid which was created in the initial step of the preceding section for this purpose, that is, connecting to the master from the slave. trigger_file: When a slave is configured as a standby, it will continue to restore the XLOG records from the master. The trigger_file parameter specifies what is used to trigger a slave, in order to switch over its duties from standby and take over as master or primary server. At this stage, the slave is fully configured now and we can start the slave server; then, the replication process begins. This is shown in step 8 of the preceding section. In steps 9 and 10 of the preceding section, we are simply testing our replication. We first begin by creating a test database, then we log in to the test database and create a table by the name testtable, and then we begin inserting some records into the testtable table. Now, our purpose is to see whether these changes are replicated across the slave. To test this, we log in to the slave on the test database and then query the records from the testtable table, as seen in step 10 of the preceding section. The final result that we see is that all the records that are changed/inserted on the primary server are visible on the slave. This completes our streaming replication's setup and configuration. Replication using Slony-I Here, we are going to set up replication using Slony-I. We will be setting up the replication of table data between two databases on the same server. Getting ready The steps performed in this recipe are carried out on a CentOS Version 6 machine. It is also important to remove the directives related to hot streaming replication prior to setting up replication using Slony-I. We will first need to install Slony-I. The following steps need to be performed in order to install Slony-I: First, go to http://slony.info/downloads/2.2/source/ and download the given software. Once you have downloaded the Slony-I software, the next step is to unzip the .tar file and then go the newly created directory. Before doing this, please ensure that you have the postgresql-devel package for the corresponding PostgreSQL version installed before you install Slony-I: tar xvfj slony1-2.2.3.tar.bz2  cd slony1-2.2.3 In the next step, we are going to configure, compile, and build the software: ./configure --with-pgconfigdir=/usr/pgsql-9.3/bin/ make make install How to do it... You need to perform the following sequence of steps, in order to replicate data between two tables using Slony-I replication: First, start the PostgreSQL server if you have not already started it: pg_ctl -D $PGDATA start In the next step, we will be creating two databases, test1 and test2, which will be used as the source and target databases respectively: createdb test1 createdb test2 In the next step, we will create the t_test table on the source database, test1, and insert some records into it: psql -d test1 test1=# create table t_test (id numeric primary key, name varchar);   test1=# insert into t_test values(1,'A'),(2,'B'), (3,'C'); We will now set up the target database by copying the table definitions from the test1 source database: pg_dump -s -p 5432 -h localhost test1 | psql -h localhost -p 5432 test2 We will now connect to the target database, test2, and verify that there is no data in the tables of the test2 database: psql -d test2 test2=# select * from t_test; We will now set up a slonik script for the master-slave, that is source/target, setup. In this scenario, since we are replicating between two different databases on the same server, the only different connection string option will be the database name: cd /usr/pgsql-9.3/bin vi init_master.slonik   #!/bin/sh cluster name = mycluster; node 1 admin conninfo = 'dbname=test1 host=localhost port=5432 user=postgres password=postgres'; node 2 admin conninfo = 'dbname=test2 host=localhost port=5432 user=postgres password=postgres'; init cluster ( id=1); create set (id=1, origin=1); set add table(set id=1, origin=1, id=1, fully qualified name = 'public.t_test'); store node (id=2, event node = 1); store path (server=1, client=2, conninfo='dbname=test1 host=localhost port=5432 user=postgres password=postgres'); store path (server=2, client=1, conninfo='dbname=test2 host=localhost port=5432 user=postgres password=postgres'); store listen (origin=1, provider = 1, receiver = 2);  store listen (origin=2, provider = 2, receiver = 1); We will now create a slonik script for subscription to the slave, that is, target: cd /usr/pgsql-9.3/bin vi init_slave.slonik #!/bin/sh cluster name = mycluster; node 1 admin conninfo = 'dbname=test1 host=localhost port=5432 user=postgres password=postgres'; node 2 admin conninfo = 'dbname=test2 host=localhost port=5432 user=postgres password=postgres'; subscribe set ( id = 1, provider = 1, receiver = 2, forward = no); We will now run the init_master.slonik script created in step 6 and run this on the master, as follows: cd /usr/pgsql-9.3/bin   slonik init_master.slonik We will now run the init_slave.slonik script created in step 7 and run this on the slave, that is, target: cd /usr/pgsql-9.3/bin   slonik init_slave.slonik In the next step, we will start the master slon daemon: nohup slon mycluster "dbname=test1 host=localhost port=5432 user=postgres password=postgres" & In the next step, we will start the slave slon daemon: nohup slon mycluster "dbname=test2 host=localhost port=5432 user=postgres password=postgres" & Next, we will connect to the master, that is, the test1 source database, and insert some records in the t_test table: psql -d test1 test1=# insert into t_test values (5,'E'); We will now test for the replication by logging on to the slave, that is, the test2 target database, and see whether the inserted records in the t_test table are visible: psql -d test2   test2=# select * from t_test; id | name ----+------ 1 | A 2 | B 3 | C 5 | E (4 rows) How it works... We will now discuss the steps performed in the preceding section: In step 1, we first start the PostgreSQL server if it is not already started. In step 2, we create two databases, namely test1 and test2, that will serve as our source (master) and target (slave) databases. In step 3, we log in to the test1 source database, create a t_test table, and insert some records into the table. In step 4, we set up the target database, test2, by copying the table definitions present in the source database and loading them into test2 using the pg_dump utility. In step 5, we log in to the target database, test2, and verify that there are no records present in the t_test table because in step 4, we only extracted the table definitions into the test2 database from the test1 database. In step 6, we set up a slonik script for the master-slave replication setup. In the init_master.slonik file, we first define the cluster name as mycluster. We then define the nodes in the cluster. Each node will have a number associated with a connection string, which contains database connection information. The node entry is defined both for the source and target databases. The store_path commands are necessary, so that each node knows how to communicate with the other. In step 7, we set up a slonik script for the subscription of the slave, that is, the test2 target database. Once again, the script contains information such as the cluster name and the node entries that are designated a unique number related to connection string information. It also contains a subscriber set. In step 8, we run the init_master.slonik file on the master. Similarly, in step 9, we run the init_slave.slonik file on the slave. In step 10, we start the master slon daemon. In step 11, we start the slave slon daemon. The subsequent steps, 12 and 13, are used to test for replication. For this purpose, in step 12 of the preceding section, we first log in to the test1 source database and insert some records into the t_test table. To check whether the newly inserted records have been replicated in the target database, test2, we log in to the test2 database in step 13. The result set obtained from the output of the query confirms that the changed/inserted records on the t_test table in the test1 database are successfully replicated across the target database, test2. For more information on Slony-I replication, go to http://slony.info/documentation/tutorial.html. There's more... If you are using Slony-I for replication between two different servers, in addition to the steps mentioned in the How to do it… section, you will also have to enable authentication information in the pg_hba.conf file existing on both the source and target servers. For example, let's assume that the source server's IP is 192.168.16.44 and the target server's IP is 192.168.16.56 and we are using a user named super to replicate the data. If this is the situation, then in the source server's pg_hba.conf file, we will have to enter the information, as follows: host         postgres         super     192.168.16.44/32           md5 Similarly, in the target server's pg_hba.conf file, we will have to enter the authentication information, as follows: host         postgres         super     192.168.16.56/32           md5 Also, in the shell scripts that were used for Slony-I, wherever the connection information for the host is localhost that entry will need to be replaced by the source and target server's IP addresses. Replication using Londiste In this recipe, we are going to show you how to replicate data using Londiste. Getting ready For this setup, we are using the same host CentOS Linux machine to replicate data between two databases. This can also be set up using two separate Linux machines running on VMware, VirtualBox, or any other virtualization software. It is assumed that the latest version of PostgreSQL, version 9.3, is installed. We used CentOS Version 6 as the Linux operating system for this exercise. To set up Londiste replication on the Linux machine, perform the following steps: Go to http://pgfoundry.org/projects/skytools/ and download the latest version of Skytools 3.2, that is, tarball skytools-3.2.tar.gz. Extract the tarball file, as follows: tar -xvzf skytools-3.2.tar.gz Go to the new location and build and compile the software: cd skytools-3.2 ./configure --prefix=/var/lib/pgsql/9.3/Sky –with-pgconfig=/usr/pgsql-9.3/bin/pg_config   make   make install Also, set the PYTHONPATH environment variable, as shown here. Alternatively, you can also set it in the .bash_profile script: export PYTHONPATH=/opt/PostgreSQL/9.2/Sky/lib64/python2.6/site-packages/ How to do it... We are going to perform the following sequence of steps to set up replication between two different databases using Londiste. First, create the two databases between which replication has to occur: createdb node1 createdb node2 Populate the node1 database with data using the pgbench utility: pgbench -i -s 2 -F 80 node1 Add any primary key and foreign keys to the tables in the node1 database that are needed for replication. Create the following .sql file and add the following lines to it: Vi /tmp/prepare_pgbenchdb_for_londiste.sql -- add primary key to history table ALTER TABLE pgbench_history ADD COLUMN hid SERIAL PRIMARY KEY;   -- add foreign keys ALTER TABLE pgbench_tellers ADD CONSTRAINT pgbench_tellers_branches_fk FOREIGN KEY(bid) REFERENCES pgbench_branches; ALTER TABLE pgbench_accounts ADD CONSTRAINT pgbench_accounts_branches_fk FOREIGN KEY(bid) REFERENCES pgbench_branches; ALTER TABLE pgbench_history ADD CONSTRAINT pgbench_history_branches_fk FOREIGN KEY(bid) REFERENCES pgbench_branches; ALTER TABLE pgbench_history ADD CONSTRAINT pgbench_history_tellers_fk FOREIGN KEY(tid) REFERENCES pgbench_tellers; ALTER TABLE pgbench_history ADD CONSTRAINT pgbench_history_accounts_fk FOREIGN KEY(aid) REFERENCES pgbench_accounts; We will now load the .sql file created in the previous step and load it into the database: psql node1 -f /tmp/prepare_pgbenchdb_for_londiste.sql We will now populate the node2 database with table definitions from the tables in the node1 database: pg_dump -s -t 'pgbench*' node1 > /tmp/tables.sql psql -f /tmp/tables.sql node2 Now starts the process of replication. We will first create the londiste.ini configuration file with the following parameters in order to set up the root node for the source database, node1: Vi londiste.ini   [londiste3] job_name = first_table db = dbname=node1 queue_name = replication_queue logfile = /home/postgres/log/londiste.log pidfile = /home/postgres/pid/londiste.pid In the next step, we are going to use the londiste.ini configuration file created in the previous step to set up the root node for the node1 database, as shown here: [postgres@localhost bin]$ ./londiste3 londiste3.ini create-root node1 dbname=node1   2014-12-09 18:54:34,723 2335 WARNING No host= in public connect string, bad idea 2014-12-09 18:54:35,210 2335 INFO plpgsql is installed 2014-12-09 18:54:35,217 2335 INFO pgq is installed 2014-12-09 18:54:35,225 2335 INFO pgq.get_batch_cursor is installed 2014-12-09 18:54:35,227 2335 INFO pgq_ext is installed 2014-12-09 18:54:35,228 2335 INFO pgq_node is installed 2014-12-09 18:54:35,230 2335 INFO londiste is installed 2014-12-09 18:54:35,232 2335 INFO londiste.global_add_table is installed 2014-12-09 18:54:35,281 2335 INFO Initializing node 2014-12-09 18:54:35,285 2335 INFO Location registered 2014-12-09 18:54:35,447 2335 INFO Node "node1" initialized for queue "replication_queue" with type "root" 2014-12-09 18:54:35,465 2335 INFO Don We will now run the worker daemon for the root node: [postgres@localhost bin]$ ./londiste3 londiste3.ini worker 2014-12-09 18:55:17,008 2342 INFO Consumer uptodate = 1 In the next step, we will create a slave.ini configuration file in order to make a leaf node for the node2 target database: Vi slave.ini [londiste3] job_name = first_table_slave db = dbname=node2 queue_name = replication_queue logfile = /home/postgres/log/londiste_slave.log pidfile = /home/postgres/pid/londiste_slave.pid We will now initialize the node in the target database: ./londiste3 slave.ini create-leaf node2 dbname=node2 –provider=dbname=node1 2014-12-09 18:57:22,769 2408 WARNING No host= in public connect string, bad idea 2014-12-09 18:57:22,778 2408 INFO plpgsql is installed 2014-12-09 18:57:22,778 2408 INFO Installing pgq 2014-12-09 18:57:22,778 2408 INFO   Reading from /var/lib/pgsql/9.3/Sky/share/skytools3/pgq.sql 2014-12-09 18:57:23,211 2408 INFO pgq.get_batch_cursor is installed 2014-12-09 18:57:23,212 2408 INFO Installing pgq_ext 2014-12-09 18:57:23,213 2408 INFO   Reading from /var/lib/pgsql/9.3/Sky/share/skytools3/pgq_ext.sql 2014-12-09 18:57:23,454 2408 INFO Installing pgq_node 2014-12-09 18:57:23,455 2408 INFO   Reading from /var/lib/pgsql/9.3/Sky/share/skytools3/pgq_node.sql 2014-12-09 18:57:23,729 2408 INFO Installing londiste 2014-12-09 18:57:23,730 2408 INFO   Reading from /var/lib/pgsql/9.3/Sky/share/skytools3/londiste.sql 2014-12-09 18:57:24,391 2408 INFO londiste.global_add_table is installed 2014-12-09 18:57:24,575 2408 INFO Initializing node 2014-12-09 18:57:24,705 2408 INFO Location registered 2014-12-09 18:57:24,715 2408 INFO Location registered 2014-12-09 18:57:24,744 2408 INFO Subscriber registered: node2 2014-12-09 18:57:24,748 2408 INFO Location registered 2014-12-09 18:57:24,750 2408 INFO Location registered 2014-12-09 18:57:24,757 2408 INFO Node "node2" initialized for queue "replication_queue" with type "leaf" 2014-12-09 18:57:24,761 2408 INFO Done We will now launch the worker daemon for the target database, that is, node2: [postgres@localhost bin]$ ./londiste3 slave.ini worker 2014-12-09 18:58:53,411 2423 INFO Consumer uptodate = 1 We will now create the configuration file, that is pgqd.ini, for the ticker daemon: vi pgqd.ini   [pgqd] logfile = /home/postgres/log/pgqd.log pidfile = /home/postgres/pid/pgqd.pid Using the configuration file created in the previous step, we will launch the ticker daemon: [postgres@localhost bin]$ ./pgqd pgqd.ini 2014-12-09 19:05:56.843 2542 LOG Starting pgqd 3.2 2014-12-09 19:05:56.844 2542 LOG auto-detecting dbs ... 2014-12-09 19:05:57.257 2542 LOG node1: pgq version ok: 3.2 2014-12-09 19:05:58.130 2542 LOG node2: pgq version ok: 3.2 We will now add all the tables to the replication on the root node: [postgres@localhost bin]$ ./londiste3 londiste3.ini add-table --all 2014-12-09 19:07:26,064 2614 INFO Table added: public.pgbench_accounts 2014-12-09 19:07:26,161 2614 INFO Table added: public.pgbench_branches 2014-12-09 19:07:26,238 2614 INFO Table added: public.pgbench_history 2014-12-09 19:07:26,287 2614 INFO Table added: public.pgbench_tellers Similarly, add all the tables to the replication on the leaf node: [postgres@localhost bin]$ ./londiste3 slave.ini add-table –all We will now generate some traffic on the node1 source database: pgbench -T 10 -c 5 node1 We will now use the compare utility available with the londiste3 command to check the tables in both the nodes; that is, both the source database (node1) and destination database (node2) have the same amount of data: [postgres@localhost bin]$ ./londiste3 slave.ini compare   2014-12-09 19:26:16,421 2982 INFO Checking if node1 can be used for copy 2014-12-09 19:26:16,424 2982 INFO Node node1 seems good source, using it 2014-12-09 19:26:16,425 2982 INFO public.pgbench_accounts: Using node node1 as provider 2014-12-09 19:26:16,441 2982 INFO Provider: node1 (root) 2014-12-09 19:26:16,446 2982 INFO Locking public.pgbench_accounts 2014-12-09 19:26:16,447 2982 INFO Syncing public.pgbench_accounts 2014-12-09 19:26:18,975 2982 INFO Counting public.pgbench_accounts 2014-12-09 19:26:19,401 2982 INFO srcdb: 200000 rows, checksum=167607238449 2014-12-09 19:26:19,706 2982 INFO dstdb: 200000 rows, checksum=167607238449 2014-12-09 19:26:19,715 2982 INFO Checking if node1 can be used for copy 2014-12-09 19:26:19,716 2982 INFO Node node1 seems good source, using it 2014-12-09 19:26:19,716 2982 INFO public.pgbench_branches: Using node node1 as provider 2014-12-09 19:26:19,730 2982 INFO Provider: node1 (root) 2014-12-09 19:26:19,734 2982 INFO Locking public.pgbench_branches 2014-12-09 19:26:19,734 2982 INFO Syncing public.pgbench_branches 2014-12-09 19:26:22,772 2982 INFO Counting public.pgbench_branches 2014-12-09 19:26:22,804 2982 INFO srcdb: 2 rows, checksum=-3078609798 2014-12-09 19:26:22,812 2982 INFO dstdb: 2 rows, checksum=-3078609798 2014-12-09 19:26:22,866 2982 INFO Checking if node1 can be used for copy 2014-12-09 19:26:22,877 2982 INFO Node node1 seems good source, using it 2014-12-09 19:26:22,878 2982 INFO public.pgbench_history: Using node node1 as provider 2014-12-09 19:26:22,919 2982 INFO Provider: node1 (root) 2014-12-09 19:26:22,931 2982 INFO Locking public.pgbench_history 2014-12-09 19:26:22,932 2982 INFO Syncing public.pgbench_history 2014-12-09 19:26:25,963 2982 INFO Counting public.pgbench_history 2014-12-09 19:26:26,008 2982 INFO srcdb: 715 rows, checksum=9467587272 2014-12-09 19:26:26,020 2982 INFO dstdb: 715 rows, checksum=9467587272 2014-12-09 19:26:26,056 2982 INFO Checking if node1 can be used for copy 2014-12-09 19:26:26,063 2982 INFO Node node1 seems good source, using it 2014-12-09 19:26:26,064 2982 INFO public.pgbench_tellers: Using node node1 as provider 2014-12-09 19:26:26,100 2982 INFO Provider: node1 (root) 2014-12-09 19:26:26,108 2982 INFO Locking public.pgbench_tellers 2014-12-09 19:26:26,109 2982 INFO Syncing public.pgbench_tellers 2014-12-09 19:26:29,144 2982 INFO Counting public.pgbench_tellers 2014-12-09 19:26:29,176 2982 INFO srcdb: 20 rows, checksum=4814381032 2014-12-09 19:26:29,182 2982 INFO dstdb: 20 rows, checksum=4814381032 How it works... The following is an explanation of the steps performed in the preceding section: Initially, in step 1, we create two databases, that is node1 and node2, that are used as the source and target databases, respectively, from a replication perspective. In step 2, we populate the node1 database using the pgbench utility. In step 3 of the preceding section, we add and define the respective primary key and foreign key relationships on different tables and put these DDL commands in a .sql file. In step 4, we execute these DDL commands stated in step 3 on the node1 database; thus, in this way, we force the primary key and foreign key definitions on the tables in the pgbench schema in the node1 database. In step 5, we extract the table definitions from the tables in the pgbench schema in the node1 database and load these definitions in the node2 database. We will now discuss steps 6 to 8 of the preceding section. In step 6, we create the configuration file, which is then used in step 7 to create the root node for the node1 source database. In step 8, we will launch the worker daemon for the root node. Regarding the entries mentioned in the configuration file in step 6, we first define a job that must have a name, so that distinguished processes can be easily identified. Then, we define a connect string with information to connect to the source database, that is node1, and then we define the name of the replication queue involved. Finally, we define the location of the log and pid files. We will now discuss steps 9 to 11 of the preceding section. In step 9, we define the configuration file, which is then used in step 10 to create the leaf node for the target database, that is node2. In step 11, we launch the worker daemon for the leaf node. The entries in the configuration file in step 9 contain the job_name connect string in order to connect to the target database, that is node2, the name of the replication queue involved, and the location of log and pid involved. The key part in step 11 is played by the slave, that is the target database—to find the master or provider, that is source database node1. We will now talk about steps 12 and 13 of the preceding section. In step 12, we define the ticker configuration, with the help of which we launch the ticker process mentioned in step 13. Once the ticker daemon has started successfully, we have all the components and processes setup and needed for replication; however, we have not yet defined what the system needs to replicate. In step 14 and 15, we define the tables to the replication that is set on both the source and target databases, that is node1 and node2, respectively. Finally, we will talk about steps 16 and 17 of the preceding section. Here, at this stage, we are testing the replication that was set up between the node1 source database and the node2 target database. In step 16, we generate some traffic on the node1 source database by running pgbench with five parallel database connections and generating traffic for 10 seconds. In step 17, we check whether the tables on both the source and target databases have the same data. For this purpose, we use the compare command on the provider and subscriber nodes and then count and checksum the rows on both sides. A partial output from the preceding section tells you that the data has been successfully replicated between all the tables that are part of the replication set up between the node1 source database and the node2 destination database, as the count and checksum of rows for all the tables on the source and target destination databases are matching: 2014-12-09 19:26:18,975 2982 INFO Counting public.pgbench_accounts 2014-12-09 19:26:19,401 2982 INFO srcdb: 200000 rows, checksum=167607238449 2014-12-09 19:26:19,706 2982 INFO dstdb: 200000 rows, checksum=167607238449   2014-12-09 19:26:22,772 2982 INFO Counting public.pgbench_branches 2014-12-09 19:26:22,804 2982 INFO srcdb: 2 rows, checksum=-3078609798 2014-12-09 19:26:22,812 2982 INFO dstdb: 2 rows, checksum=-3078609798   2014-12-09 19:26:25,963 2982 INFO Counting public.pgbench_history 2014-12-09 19:26:26,008 2982 INFO srcdb: 715 rows, checksum=9467587272 2014-12-09 19:26:26,020 2982 INFO dstdb: 715 rows, checksum=9467587272   2014-12-09 19:26:29,144 2982 INFO Counting public.pgbench_tellers 2014-12-09 19:26:29,176 2982 INFO srcdb: 20 rows, checksum=4814381032 2014-12-09 19:26:29,182 2982 INFO dstdb: 20 rows, checksum=4814381032 Summary This article demonstrates the high availability and replication concepts in PostgreSQL. After reading this chapter, you will be able to implement high availability and replication options using different techniques including streaming replication, Slony-I replication and replication using Longdiste. Resources for Article: Further resources on this subject: Running a PostgreSQL Database Server [article] Securing the WAL Stream [article] Recursive queries [article]

In this article by David R. Heffelfinger, the author of Java EE 7 Development with NetBeans 8, we will introduce Contexts and Dependency Injection (CDI) and other aspects of it. CDI can be used to simplify integrating the different layers of a Java EE application. For example, CDI allows us to use a session bean as a managed bean, so that we can take advantage of the EJB features, such as transactions, directly in our managed beans. In this article, we will cover the following topics: Introduction to CDI Qualifiers Stereotypes Interceptor binding types Custom scopes (For more resources related to this topic, see here.) Introduction to CDI JavaServer Faces (JSF) web applications employing CDI are very similar to JSF applications without CDI; the main difference is that instead of using JSF managed beans for our model and controllers, we use CDI named beans. What makes CDI applications easier to develop and maintain are the excellent dependency injection capabilities of the CDI API. Just as with other JSF applications, CDI applications use facelets as their view technology. The following example illustrates a typical markup for a JSF page using CDI: <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html      >    <h:head>        <title>Create New Customer</title>    </h:head>    <h:body>        <h:form>            <h3>Create New Customer</h3>            <h:panelGrid columns="3">                <h:outputLabel for="firstName" value="First Name"/>                <h:inputText id="firstName" value="#{customer.firstName}"/>                <h:message for="firstName"/>                  <h:outputLabel for="middleName" value="Middle Name"/>                <h:inputText id="middleName"                  value="#{customer.middleName}"/>                <h:message for="middleName"/>                  <h:outputLabel for="lastName" value="Last Name"/>                <h:inputText id="lastName" value="#{customer.lastName}"/>                <h:message for="lastName"/>                  <h:outputLabel for="email" value="Email Address"/>                <h:inputText id="email" value="#{customer.email}"/>                <h:message for="email"/>                <h:panelGroup/>                <h:commandButton value="Submit"                  action="#{customerController.navigateToConfirmation}"/>            </h:panelGrid>        </h:form>    </h:body> </html> As we can see, the preceding markup doesn't look any different from the markup used for a JSF application that does not use CDI. The page renders as follows (shown after entering some data): In our page markup, we have JSF components that use Unified Expression Language expressions to bind themselves to CDI named bean properties and methods. Let's take a look at the customer bean first: package com.ensode.cdiintro.model;   import java.io.Serializable; import javax.enterprise.context.RequestScoped; import javax.inject.Named;   @Named @RequestScoped public class Customer implements Serializable {      private String firstName;    private String middleName;    private String lastName;    private String email;      public Customer() {    }      public String getFirstName() {        return firstName;    }      public void setFirstName(String firstName) {        this.firstName = firstName;    }      public String getMiddleName() {        return middleName;    }      public void setMiddleName(String middleName) {        this.middleName = middleName;    }      public String getLastName() {        return lastName;    }      public void setLastName(String lastName) {        this.lastName = lastName;    }      public String getEmail() {        return email;    }      public void setEmail(String email) {        this.email = email;    } } The @Named annotation marks this class as a CDI named bean. By default, the bean's name will be the class name with its first character switched to lowercase (in our example, the name of the bean is "customer", since the class name is Customer). We can override this behavior if we wish by passing the desired name to the value attribute of the @Named annotation, as follows: @Named(value="customerBean") A CDI named bean's methods and properties are accessible via facelets, just like regular JSF managed beans. Just like JSF managed beans, CDI named beans can have one of several scopes as listed in the following table. The preceding named bean has a scope of request, as denoted by the @RequestScoped annotation. Scope Annotation Description Request @RequestScoped Request scoped beans are shared through the duration of a single request. A single request could refer to an HTTP request, an invocation to a method in an EJB, a web service invocation, or sending a JMS message to a message-driven bean. Session @SessionScoped Session scoped beans are shared across all requests in an HTTP session. Each user of an application gets their own instance of a session scoped bean. Application @ApplicationScoped Application scoped beans live through the whole application lifetime. Beans in this scope are shared across user sessions. Conversation @ConversationScoped The conversation scope can span multiple requests, and is typically shorter than the session scope. Dependent @Dependent Dependent scoped beans are not shared. Any time a dependent scoped bean is injected, a new instance is created. As we can see, CDI has equivalent scopes to all JSF scopes. Additionally, CDI adds two additional scopes. The first CDI-specific scope is the conversation scope, which allows us to have a scope that spans across multiple requests, but is shorter than the session scope. The second CDI-specific scope is the dependent scope, which is a pseudo scope. A CDI bean in the dependent scope is a dependent object of another object; beans in this scope are instantiated when the object they belong to is instantiated and they are destroyed when the object they belong to is destroyed. Our application has two CDI named beans. We already discussed the customer bean. The other CDI named bean in our application is the controller bean: package com.ensode.cdiintro.controller;   import com.ensode.cdiintro.model.Customer; import javax.enterprise.context.RequestScoped; import javax.inject.Inject; import javax.inject.Named;   @Named @RequestScoped public class CustomerController {      @Inject    private Customer customer;      public Customer getCustomer() {        return customer;    }      public void setCustomer(Customer customer) {        this.customer = customer;    }      public String navigateToConfirmation() {        //In a real application we would        //Save customer data to the database here.          return "confirmation";    } } In the preceding class, an instance of the Customer class is injected at runtime; this is accomplished via the @Inject annotation. This annotation allows us to easily use dependency injection in CDI applications. Since the Customer class is annotated with the @RequestScoped annotation, a new instance of Customer will be injected for every request. The navigateToConfirmation() method in the preceding class is invoked when the user clicks on the Submit button on the page. The navigateToConfirmation() method works just like an equivalent method in a JSF managed bean would, that is, it returns a string and the application navigates to an appropriate page based on the value of that string. Like with JSF, by default, the target page's name with an .xhtml extension is the return value of this method. For example, if no exceptions are thrown in the navigateToConfirmation() method, the user is directed to a page named confirmation.xhtml: <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html      >    <h:head>        <title>Success</title>    </h:head>    <h:body>        New Customer created successfully.        <h:panelGrid columns="2" border="1" cellspacing="0">            <h:outputLabel for="firstName" value="First Name"/>            <h:outputText id="firstName" value="#{customer.firstName}"/>              <h:outputLabel for="middleName" value="Middle Name"/>            <h:outputText id="middleName"              value="#{customer.middleName}"/>              <h:outputLabel for="lastName" value="Last Name"/>            <h:outputText id="lastName" value="#{customer.lastName}"/>              <h:outputLabel for="email" value="Email Address"/>            <h:outputText id="email" value="#{customer.email}"/>          </h:panelGrid>    </h:body> </html> Again, there is nothing special we need to do to access the named beans properties from the preceding markup. It works just as if the bean was a JSF managed bean. The preceding page renders as follows: As we can see, CDI applications work just like JSF applications. However, CDI applications have several advantages over JSF, for example (as we mentioned previously) CDI beans have additional scopes not found in JSF. Additionally, using CDI allows us to decouple our Java code from the JSF API. Also, as we mentioned previously, CDI allows us to use session beans as named beans. Qualifiers In some instances, the type of bean we wish to inject into our code may be an interface or a Java superclass, but we may be interested in injecting a subclass or a class implementing the interface. For cases like this, CDI provides qualifiers we can use to indicate the specific type we wish to inject into our code. A CDI qualifier is an annotation that must be decorated with the @Qualifier annotation. This annotation can then be used to decorate the specific subclass or interface. In this section, we will develop a Premium qualifier for our customer bean; premium customers could get perks that are not available to regular customers, for example, discounts. Creating a CDI qualifier with NetBeans is very easy; all we need to do is go to File | New File, select the Contexts and Dependency Injection category, and select the Qualifier Type file type. In the next step in the wizard, we need to enter a name and a package for our qualifier. After these two simple steps, NetBeans generates the code for our qualifier: package com.ensode.cdiintro.qualifier;   import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.ElementType.FIELD; import static java.lang.annotation.ElementType.PARAMETER; import static java.lang.annotation.ElementType.METHOD; import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.Retention; import java.lang.annotation.Target; import javax.inject.Qualifier;   @Qualifier @Retention(RUNTIME) @Target({METHOD, FIELD, PARAMETER, TYPE}) public @interface Premium { } Qualifiers are standard Java annotations. Typically, they have retention of runtime and can target methods, fields, parameters, or types. The only difference between a qualifier and a standard annotation is that qualifiers are decorated with the @Qualifier annotation. Once we have our qualifier in place, we need to use it to decorate the specific subclass or interface implementation, as shown in the following code: package com.ensode.cdiintro.model;   import com.ensode.cdiintro.qualifier.Premium; import javax.enterprise.context.RequestScoped; import javax.inject.Named;   @Named @RequestScoped @Premium public class PremiumCustomer extends Customer {      private Integer discountCode;      public Integer getDiscountCode() {        return discountCode;    }      public void setDiscountCode(Integer discountCode) {        this.discountCode = discountCode;    } } Once we have decorated the specific instance we need to qualify, we can use our qualifiers in the client code to specify the exact type of dependency we need: package com.ensode.cdiintro.controller;   import com.ensode.cdiintro.model.Customer; import com.ensode.cdiintro.model.PremiumCustomer; import com.ensode.cdiintro.qualifier.Premium;   import java.util.logging.Level; import java.util.logging.Logger; import javax.enterprise.context.RequestScoped; import javax.inject.Inject; import javax.inject.Named;   @Named @RequestScoped public class PremiumCustomerController {      private static final Logger logger = Logger.getLogger(            PremiumCustomerController.class.getName());    @Inject    @Premium    private Customer customer;      public String saveCustomer() {          PremiumCustomer premiumCustomer =          (PremiumCustomer) customer;          logger.log(Level.INFO, "Saving the following information n"                + "{0} {1}, discount code = {2}",                new Object[]{premiumCustomer.getFirstName(),                    premiumCustomer.getLastName(),                    premiumCustomer.getDiscountCode()});          //If this was a real application, we would have code to save        //customer data to the database here.          return "premium_customer_confirmation";    } } Since we used our @Premium qualifier to decorate the customer field, an instance of the PremiumCustomer class is injected into that field. This is because this class is also decorated with the @Premium qualifier. As far as our JSF pages go, we simply access our named bean as usual using its name, as shown in the following code; <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html      >    <h:head>        <title>Create New Premium Customer</title>    </h:head>    <h:body>        <h:form>            <h3>Create New Premium Customer</h3>            <h:panelGrid columns="3">                <h:outputLabel for="firstName" value="First Name"/>                 <h:inputText id="firstName"                    value="#{premiumCustomer.firstName}"/>                <h:message for="firstName"/>                  <h:outputLabel for="middleName" value="Middle Name"/>                <h:inputText id="middleName"                     value="#{premiumCustomer.middleName}"/>                <h:message for="middleName"/>                  <h:outputLabel for="lastName" value="Last Name"/>                <h:inputText id="lastName"                    value="#{premiumCustomer.lastName}"/>                <h:message for="lastName"/>                  <h:outputLabel for="email" value="Email Address"/>                <h:inputText id="email"                    value="#{premiumCustomer.email}"/>                <h:message for="email"/>                  <h:outputLabel for="discountCode" value="Discount Code"/>                <h:inputText id="discountCode"                    value="#{premiumCustomer.discountCode}"/>                <h:message for="discountCode"/>                   <h:panelGroup/>                <h:commandButton value="Submit"                      action="#{premiumCustomerController.saveCustomer}"/>            </h:panelGrid>        </h:form>    </h:body> </html> In this example, we are using the default name for our bean, which is the class name with the first letter switched to lowercase. Now, we are ready to test our application: After submitting the page, we can see the confirmation page. Stereotypes A CDI stereotype allows us to create new annotations that bundle up several CDI annotations. For example, if we need to create several CDI named beans with a scope of session, we would have to use two annotations in each of these beans, namely @Named and @SessionScoped. Instead of having to add two annotations to each of our beans, we could create a stereotype and annotate our beans with it. To create a CDI stereotype in NetBeans, we simply need to create a new file by selecting the Contexts and Dependency Injection category and the Stereotype file type. Then, we need to enter a name and package for our new stereotype. At this point, NetBeans generates the following code: package com.ensode.cdiintro.stereotype;   import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.ElementType.FIELD; import static java.lang.annotation.ElementType.METHOD; import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.Retention; import java.lang.annotation.Target; import javax.enterprise.inject.Stereotype;   @Stereotype @Retention(RUNTIME) @Target({METHOD, FIELD, TYPE}) public @interface NamedSessionScoped { } Now, we simply need to add the CDI annotations that we want the classes annotated with our stereotype to use. In our case, we want them to be named beans and have a scope of session; therefore, we add the @Named and @SessionScoped annotations as shown in the following code: package com.ensode.cdiintro.stereotype;   import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.ElementType.FIELD; import static java.lang.annotation.ElementType.METHOD; import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.Retention; import java.lang.annotation.Target; import javax.enterprise.context.SessionScoped; import javax.enterprise.inject.Stereotype; import javax.inject.Named;   @Named @SessionScoped @Stereotype @Retention(RUNTIME) @Target({METHOD, FIELD, TYPE}) public @interface NamedSessionScoped { } Now we can use our stereotype in our own code: package com.ensode.cdiintro.beans;   import com.ensode.cdiintro.stereotype.NamedSessionScoped; import java.io.Serializable;   @NamedSessionScoped public class StereotypeClient implements Serializable {      private String property1;    private String property2;      public String getProperty1() {        return property1;    }      public void setProperty1(String property1) {        this.property1 = property1;    }      public String getProperty2() {        return property2;    }      public void setProperty2(String property2) {        this.property2 = property2;    } } We annotated the StereotypeClient class with our NamedSessionScoped stereotype, which is equivalent to using the @Named and @SessionScoped annotations. Interceptor binding types One of the advantages of EJBs is that they allow us to easily perform aspect-oriented programming (AOP) via interceptors. CDI allows us to write interceptor binding types; this lets us bind interceptors to beans and the beans do not have to depend on the interceptor directly. Interceptor binding types are annotations that are themselves annotated with @InterceptorBinding. Creating an interceptor binding type in NetBeans involves creating a new file, selecting the Contexts and Dependency Injection category, and selecting the Interceptor Binding Type file type. Then, we need to enter a class name and select or enter a package for our new interceptor binding type. At this point, NetBeans generates the code for our interceptor binding type: package com.ensode.cdiintro.interceptorbinding;   import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.ElementType.METHOD; import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.Inherited; import java.lang.annotation.Retention; import java.lang.annotation.Target; import javax.interceptor.InterceptorBinding;   @Inherited @InterceptorBinding @Retention(RUNTIME) @Target({METHOD, TYPE}) public @interface LoggingInterceptorBinding { } The generated code is fully functional; we don't need to add anything to it. In order to use our interceptor binding type, we need to write an interceptor and annotate it with our interceptor binding type, as shown in the following code: package com.ensode.cdiintro.interceptor;   import com.ensode.cdiintro.interceptorbinding.LoggingInterceptorBinding; import java.io.Serializable; import java.util.logging.Level; import java.util.logging.Logger; import javax.interceptor.AroundInvoke; import javax.interceptor.Interceptor; import javax.interceptor.InvocationContext;   @LoggingInterceptorBinding @Interceptor public class LoggingInterceptor implements Serializable{      private static final Logger logger = Logger.getLogger(            LoggingInterceptor.class.getName());      @AroundInvoke    public Object logMethodCall(InvocationContext invocationContext)            throws Exception {          logger.log(Level.INFO, new StringBuilder("entering ").append(                invocationContext.getMethod().getName()).append(                " method").toString());          Object retVal = invocationContext.proceed();          logger.log(Level.INFO, new StringBuilder("leaving ").append(                invocationContext.getMethod().getName()).append(                " method").toString());          return retVal;    } } As we can see, other than being annotated with our interceptor binding type, the preceding class is a standard interceptor similar to the ones we use with EJB session beans. In order for our interceptor binding type to work properly, we need to add a CDI configuration file (beans.xml) to our project. Then, we need to register our interceptor in beans.xml as follows: <?xml version="1.0" encoding="UTF-8"?> <beans               xsi_schemaLocation="http://>    <interceptors>          <class>        com.ensode.cdiintro.interceptor.LoggingInterceptor      </class>    </interceptors> </beans> To register our interceptor, we need to set bean-discovery-mode to all in the generated beans.xml and add the <interceptor> tag in beans.xml, with one or more nested <class> tags containing the fully qualified names of our interceptors. The final step before we can use our interceptor binding type is to annotate the class to be intercepted with our interceptor binding type: package com.ensode.cdiintro.controller;   import com.ensode.cdiintro.interceptorbinding.LoggingInterceptorBinding; import com.ensode.cdiintro.model.Customer; import com.ensode.cdiintro.model.PremiumCustomer; import com.ensode.cdiintro.qualifier.Premium; import java.util.logging.Level; import java.util.logging.Logger; import javax.enterprise.context.RequestScoped; import javax.inject.Inject; import javax.inject.Named;   @LoggingInterceptorBinding @Named @RequestScoped public class PremiumCustomerController {      private static final Logger logger = Logger.getLogger(            PremiumCustomerController.class.getName());    @Inject    @Premium    private Customer customer;      public String saveCustomer() {          PremiumCustomer premiumCustomer = (PremiumCustomer) customer;          logger.log(Level.INFO, "Saving the following information n"                + "{0} {1}, discount code = {2}",                new Object[]{premiumCustomer.getFirstName(),                    premiumCustomer.getLastName(),                    premiumCustomer.getDiscountCode()});          //If this was a real application, we would have code to save        //customer data to the database here.          return "premium_customer_confirmation";    } } Now, we are ready to use our interceptor. After executing the preceding code and examining the GlassFish log, we can see our interceptor binding type in action. The lines entering saveCustomer method and leaving saveCustomer method were added to the log by our interceptor, which was indirectly invoked by our interceptor binding type. Custom scopes In addition to providing several prebuilt scopes, CDI allows us to define our own custom scopes. This functionality is primarily meant for developers building frameworks on top of CDI, not for application developers. Nevertheless, NetBeans provides a wizard for us to create our own CDI custom scopes. To create a new CDI custom scope, we need to go to File | New File, select the Contexts and Dependency Injection category, and select the Scope Type file type. Then, we need to enter a package and a name for our custom scope. After clicking on Finish, our new custom scope is created, as shown in the following code: package com.ensode.cdiintro.scopes;   import static java.lang.annotation.ElementType.TYPE; import static java.lang.annotation.ElementType.FIELD; import static java.lang.annotation.ElementType.METHOD; import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.Inherited; import java.lang.annotation.Retention; import java.lang.annotation.Target; import javax.inject.Scope;   @Inherited @Scope // or @javax.enterprise.context.NormalScope @Retention(RUNTIME) @Target({METHOD, FIELD, TYPE}) public @interface CustomScope { } To actually use our scope in our CDI applications, we would need to create a custom context which, as mentioned previously, is primarily a concern for framework developers and not for Java EE application developers. Therefore, it is beyond the scope of this article. Interested readers can refer to JBoss Weld CDI for Java Platform, Ken Finnigan, Packt Publishing. (JBoss Weld is a popular CDI implementation and it is included with GlassFish.) Summary In this article, we covered NetBeans support for CDI, a new Java EE API introduced in Java EE 6. We provided an introduction to CDI and explained additional functionality that the CDI API provides over standard JSF. We also covered how to disambiguate CDI injected beans via CDI Qualifiers. Additionally, we covered how to group together CDI annotations via CDI stereotypes. We also, we saw how CDI can help us with AOP via interceptor binding types. Finally, we covered how NetBeans can help us create custom CDI scopes. Resources for Article: Further resources on this subject: Java EE 7 Performance Tuning and Optimization [article] Java EE 7 Developer Handbook [article] Java EE 7 with GlassFish 4 Application Server [article]

In this article, written by Jayant Varma, the author of Xcode 6 Essentials, we shall look at Xcode closely as this is going to be the tool you would use quite a lot for all aspects of your app development for Apple devices. It is a good idea to know and be familiar with the interface, the sections, shortcut keys, and so on. (For more resources related to this topic, see here.) Starting Xcode Xcode, like many other Mac applications, is found in the Applications folder or the Launchpad. On starting Xcode, you will be greeted with the launch screen that offers some entry points for working with Xcode. Mostly, you will select Create a new Xcode project or Check out an existing project , if you have an existing project to continue work on. Xcode remembers what it was doing last, so if you had a project or file open, it will open up those windows again. Creating a new project After selecting the Create a new project option, we are guided via a wizard that helps us get started. Selecting the project type The first step is to select what type of project you want to create. At the moment, there are two distinct types of projects, mobile (iOS) or desktop (OS X) that you can create. Within each of those types, you can select the type of project you want. The screenshot displays a standard configuration for iOS application projects. The templates used when the selected type of project is created are self sufficient, that is, when the Run button is pressed, the app compiles and runs. It might do nothing, as this is a minimalistic template. On selecting the type of project, we can select the next step: Setting the project options This step allows selecting the options, namely setting the application name, the organization name, identifier, language, and devices to support. In the past, the language was always set to Objective-C, however with Xcode 6, there are two options: objective-C and Swift Setting the project properties On creation, the main screen is displayed. Here it offers the option to change other details related to the application such as the version number and build. It also allows you to configure the team ID and certificates used for signing the application to test on a mobile device or for distribution to the App Store. It also allows you to set the compatibility for earlier versions. The orientation and app icons, splash screens, and so on are also set from this screen. If you want to set these up later on in the project, it is fine, this can be accessed at any time and does not stop you from development. It needs to be set prior to deploying it on a device or creating an App Store ready application. Xcode overview Let us have a look at the Xcode interface to familiarize ourselves with the same as it would help improve productivity when building your application. The top section immediately following the traffic light (window chrome) displays a Play and Stop button. This allows the project to run and stop. The breadcrumb toolbar displays the project-specific settings with respect to the product and the target. With an iOS project, it could be a particular simulator for iPhone, iPad, and so on, or a physical device (number 5 in the following screenshot). Just under this are vertical areas that are the main content area with all the files, editors, UI, and so on. These can be displayed or hidden as required and can be stacked vertically or horizontally. The distinct areas in Xcode are as follows: Project navigation (number1) Editor and assistant editor (number 2 ) and (number 3 ) Utility/inspector (number 4 ) The toolbar (number 5 ) and (number 6 ) These sections can be switched on and off (shown or hidden) as required to make space for other sections or more screen space to work with: Sections in Xcode The project section The project navigation section has three sub sections, the topmost being the project toolbar that has eight icons. These can be seen as in the following screenshot. The next sub section contains the project files and all the assets required for this project. The bottom most section consists of recently edited files and filters: You can use the keyboard shortcuts to access these areas quickly with the CMD + 1...8 keys. The eight areas available under project navigation are key and for the beginner to Xcode, this could be a bit daunting. When you run the project, the current section might change and display another where you might wonder how to get back to the project (file) navigator. Getting familiar with these is always helpful and the easiest way to navigate between these is the CMD + 1..8 keys. Project navigator ( CMD + 1 ): This displays all of the files, folders, assets, frameworks, and so on that are part of this project. This is displayed as a hierarchical view and is the way that a majority of developers access their files, folders, and so on. Symbol navigator ( CMD + 2 ): This displays all of the classes, members, and methods that are available in them. This is the easiest way to navigate quickly to a method/function, attribute/property. Search navigator ( CMD + 3 ): This allows you to search the project for a particular match. This is quite useful to find and replace text. Issues navigator ( CMD + 4 ): This displays the warning and errors that occur while typing your code or on building and running it. This also displays the results of the static analyzer. Tests navigator ( CMD + 5 ); This displays the tests that you have present in your code either added by yourself or the default ones created with the project. Debug navigator ( CMD + 6 ): This displays the information about the application when you choose to run it. It has some amazing detailed information on CPU usage, memory usage, disk usage, threads, and so on. Breakpoint navigator ( CMD + 7 ): This displays all the breakpoints in your project from all files. This also allows you to create exception and symbolic breakpoints. Log navigator ( CMD + 8 ): This displays a log of all actions carried out, namely compiling, building, and running. This is more useful when used to determine the results of automated builds The editor and assistant editor sections The second area contains the editor and assistant editor sections. These display the code, the XIB (as appropriate), storyboard files, device previews, and so on. Each of the sub sections have a jump bar on the top that relates to files and allow for navigating back and forth in the files and display the location of the file in the workspace. To the right from this is a mini issues navigator that displays all warnings and errors. In the case of the assistant editors, it also displays two buttons: one to add a new assistant editor area and another to close it.   Source code editors While we are looking at the interface, it is worth noting that the Xcode code editor is a very advanced editor with a lot of features, which is now seen as standard with a lot of text editors. Some of the features that make working with Xcode easier are as follows: Code folding : This feature helps to hide code at points such as the function declaration, loops, matching brace brackets, and so on. When a function or portion of code is folded, it hides it from view, thereby allowing you to view other areas of the code that would not be visible unless you scrolled. Syntax highlighting : This is one of the most useful features as it helps you, the developer, to visually, at a glance, differentiate your source code from variables, constants, and strings. Xcode has syntax highlighting for a couple of languages as mentioned earlier. Context help : This is one of the best features whereby when you hover over a word in the source code with OPT pressed, it shows a dotted underline and the cursor changes to a question mark. When you click on a word with the dotted underline and the question mark cursor, it displays a popup with details about that word. It also highlights all instances of that word in the file. The popup details as much information as available. If it is a variable or a function that you have added to the code, then it will display the name of the file where it was declared. If it is a word that is contained in the Apple libraries, then it displays the description and other additional details. Context jump : This is another cool feature that allows jumping to the point of declaration of that word. This is achieved by clicking on a word while keeping the CMD button pressed. In many cases, this is mainly helpful to know how the function is declared and what parameters it expects. It can also be useful to get information on other enumerators and constants used with that function. The jump could be in the same file as where you are editing the code or it could be to the header files where they are declared. Edit all in scope : This is a cool feature where you can edit all of the instances of the word together rather than using search and replace. A case scenario is if you want to change the name of a variable and ensure that all instances you are using in the file are changed but not the ones that are text, then you can use this option to quickly change it. Catching mistakes with fix-it : This is another cool feature in Xcode that will save you a lot of time and hassle. As you type text, Xcode keeps analyzing the code and looking for errors. If you have declared a variable and not used it in your code, Xcode immediately draws attention to it suggesting that the variable is an unused variable. However, if it was supposed to be a pointer and you have declared it without *; Xcode immediately flags it as an error that the interface type cannot be statically allocated. It offers a fix-it solution of inserting * and the code has a greyed * character showing where it will be added. This helps the developer fix commonly overlooked issues such as missing semicolons, missing declarations, or misspelled variable names. Code completion : This is the bit that makes writing code so much easier, type in a few letters of the function name and Xcode pops up a list of functions, constants, methods, and so on that start with those letters and displays all of the required parameters (as applicable) including the return type. When selected, it adds the token placeholders that can be replaced with the actual parameter values. The results might vary from person to person depending on the settings and the speed of the system you run Xcode on. The assistant editor The assistant editor is mainly used to display the counterparts and related files to the file open in the primary editor (generally used when working with Objective-C where the .h or.m files are the related files). The assistant editors track the contents of the editor. Xcode is quite intelligent and knows the corresponding sections and counterparts. When you click on a file, it opens up in the editor. However, pressing the OPT + Shift while clicking on the file, you would be provided with an interactive dialog to select where to open the file. The options include the primary editor or the assistant editor. You can also add assistant editors as required.   Another way to open a file quickly is to use the Open Quickly option, which has a shortcut key of CMD + Shift + O . This displays a textbox that allows accessing a file from the project. The utility/inspector section The last section contains the inspector and library. This section changes based on the type of file selected in the current editor. The inspector has 6 tabs/sections and they are as follows: The file inspector ( CMD + OPT + 1 ): This displays the physical file information for the file selected. For code files, it is the text encoding, the targets that it belongs to, and the physical file path. While for the storyboard, it is the physical file path and allows setting attributes such as auto layout and size classes (new in Xcode 6). The quick help inspector ( CMD + OPT + 2 ): This displays information about the class or object selected. The identity inspector ( CMD + OPT + 3 ): This displays the class name, ID, and others that identify the object selected. The attributes inspector ( CMD + OPT + 4 ): This displays the attributes for the object selected as if it is the initial root view controller, does it extend under the top bars or not, if it has a navigation bar or not, and others. This also displays the user-defined attributes (a new feature with Xcode 6). The size inspector ( CMD + OPT + 5 ): This displays the size of the control selected and the associated constraints that help position it on the container. The connections inspector ( CMD + OPT + 6 ): This displays the connections created in the Interface Builder between the UI and the code. The lower half of this inspector contains four options that help you work efficiently, they are as follows: The file template library : This contains the options to create a new class, protocol. The options that are available when selecting the File | New option from the menu. The code snippets library : This is a wonderful but not widely used option. This can hold code snippets that can help you avoid writing repetitive blocks of code in your app. You can drag and drop the snippet to your code in the editor. This also offers features such as shortcuts, scopes, platforms, and languages. So you can have a shortcut such as appDidLoad (for example) that inserts the code to create and populate a button. This is achieved simply by setting the platform as appropriate to iOS or OS X. After creating a code snippet, as soon as you type the first few characters, the code snippet shows up in the list of autocomplete options; The object library : This is the toolbox that contains all of the controls that you need for creating your UI, be it a button, a label, a Table View, view, View Controller, or anything else. Adding a code snippet is as easy as dragging the selected code from the editor onto the snippet area. It is a little tricky because the moment you start dragging, it could break your selection highlight. You need to select the text, click (hold) and then drag it. The media library : This contains the list of all images and other media types that are available to this project/workspace. Summary In this article, you have seen a quick tour of Xcode, keeping the shortcuts and tips handy as they really do help get things done faster. The code snippets are a wonderful feature that allow for quickly setting up commonly used code with shortcut keywords. Resources for Article: Further resources on this subject: Introducing Xcode Tools for iPhone Development [article] Xcode 4 ios: Displaying Notification Messages [article] Linking OpenCV to an iOS project [article]

In this article by Paul Goodey, author of the book Salesforce CRM – The Definitive Admin Handbook - Third Edition, we will look at the administration of Salesforce Mobile solutions that can significantly improve productivity and user satisfaction and help them access data and application functionality out of the office. (For more resources related to this topic, see here.) In the past, mobile devices that were capable of accessing software applications were very expensive. Often, these devices were regarded as a nice to have accessory by management and were seen as a company perk by field-based teams. Today, mobile devices are far more prevalent within the business environment, and organizations are increasingly realizing the benefits of using mobile phones and devices to access business applications. Salesforce has taken the lead in recognizing how mobiles have become the new standard for being connected in people's personal and professional lives. It has also highlighted how increasingly, the users of their apps are living lives connected to the Internet, but rather than sitting at a desk in the office, they are in between meetings, on the road, in planes, in trains, in cabs, or even in the queue for lunch. As a result, Salesforce has developed innovative mobile solutions that help you and your users embrace this mobile-first world in Salesforce CRM. Accessing Salesforce Mobile products Salesforce offers two varieties of mobile solutions, namely mobile browser apps and downloadable apps. Mobile browser apps, as the name suggests, are accessed using a web browser that is available on a mobile device. Downloadable apps are accessed by first downloading the client software from, say, the Apple App Store or Google Play and then installing it onto the mobile device. Mobile browser apps and downloadable apps offer various features and benefits and, as we'll see, are available for various Salesforce mobile products and device combinations. Most mobile devices these days have some degree of web browser capability, which can be used to access Salesforce CRM; however, some Salesforce mobile products are optimized for use with certain devices. By accessing a Salesforce mobile browser app, your users do not require anything to be installed. Supported mobile browsers for Salesforce are generally available on Android, Apple, BlackBerry, and Microsoft Windows 8.1 devices. Downloadable apps, on the other hand, will require the app to be first downloaded from the App Store for Apple® devices or from Google Play™ for Android™ devices and then installed on the mobile device. Salesforce mobile products' overview Salesforce has provided certain mobile products as downloadable apps only, while others have been provided as both downloadable and mobile browser-based. The following list outlines the various mobile app products, features, and capabilities used to access Salesforce CRM on mobile devices: SalesforceA Salesforce Touch Salesforce1 Salesforce Classic Salesforce Touch is no longer available and is mentioned here for completeness as this product has been recently incorporated into the Salesforce1 product. SalesforceA SalesforceA is a downloadable system administration app that allows you to manage your organization's users and view certain information for your Salesforce organization from your mobile device. Salesforce A is intended to be used by system administrators, as it is restricted to users with the Manage Users permission. The SalesforceA app provides the facilities to carry out user tasks, such as deactivating or freezing users, resetting passwords, unlocking users, editing user details, calling and emailing users, and assigning permission sets. These user task buttons are displayed as action icons, as shown in the following screenshot: These icons are presented in the action bar at the bottom of the mobile device screen, as shown in the following screenshot: In addition to the user tasks, you can view the system status and also switch between your user accounts in multiple organizations. This allows you to access different organizations and communities without having to log out and log back in to each user account. By staying logged in to multiple accounts in different organizations, you will save time by easily switching to the particular organization user account that you need to access. SalesforceA supported devices At the time of writing, the following devices are supported by Salesforce for use with the SalesforceA downloadable app: Android phones Apple iPhone Apple iPod Touch SalesforceA can be installed from Google Play™ for Android™ phones and the Apple® App Store for Apple devices. Salesforce Touch Salesforce Touch is the name of an earlier Salesforce mobile product and is no longer available. With the Spring 2014 release, Salesforce Touch was incorporated into the Salesforce1 app. Hence, both the Salesforce Touch mobile browser and Salesforce Touch downloadable apps are no longer available; however, the functionality that they once offered is available in Salesforce1, which is covered in this article. Salesforce1 Salesforce1 is Salesforce's next-generation mobile CRM platform that has been designed for Salesforce's customers, developers, and ISVs (independent software vendors) to connect mobile apps, browser apps, and third-party app services. Salesforce1 has been developed for a mobile-first environment and demonstrates how Salesforce's focus as a platform provider aims to connect enterprises with systems that can be programmed through APIs, along with mobile apps and services that can be utilized by marketing, sales, and customer service. There are two ways to use Salesforce1: either using a mobile browser app that users can access by logging into Salesforce from a supported mobile browser or downloadable apps that users can install from the App Store or Google Play. Either way, Salesforce1 allows users to access and update Salesforce data from an interface that has been optimized to navigate and work on their touchscreen mobile devices. Using Salesforce1, records can be viewed, edited, and created. Users can manage their activities, view their dashboards, and use Chatter. Salesforce1 also supports many standard objects and list views, all custom objects, plus the integration of other mobile apps and many of your organization's Salesforce customizations, including Visualforce tabs and pages. Salesforce1 supported devices At the time of writing this, the following devices are supported by Salesforce for the Salesforce1 mobile browser app: Android phones Apple iPad Apple iPhone BlackBerry Z10 Windows 8.1 phones (Beta support) Also, at the time of writing this, Salesforce specifies the following devices as being supported for the Salesforce1 downloadable app: Android phones Apple iPad Apple iPhone Salesforce1 data availability Your organization edition, the user's license type, along with the user's profile and any permission sets, determines the data that is available to the user within Salesforce1. Generally, users have the same visibility of objects, record types, fields, and page layouts that they have while accessing the full Salesforce browser app. However, at the time of writing this, not all data is available in the current release of the Salesforce1 app. In Winter 2015, these key objects are fully accessible from the Salesforce1 navigation menu: Accounts; Campaigns; Cases; Contacts; Contracts; Leads; Opportunities; Tasks; and Users. Dashboards and Events, however, are restricted to being viewable from only the Salesforce1 navigation menu. Custom objects are fully accessible if they have a tab that the user can access. For new users who are yet to build a history of recent objects, they initially see a set of default objects in the Recent section in the Salesforce1 navigation menu. The majority of standard and custom fields, and most of the related lists for the supported objects, are available on these records; however, at the time of writing this, the following exceptions exist: Rich text area field support varies (detailed shortly) Links on formula fields are not supported State and country picklist fields are not supported Related lists in Salesforce1 are restricted (detailed shortly) Rich text area field support varies Support for rich text area fields varies by the version of Salesforce1 and the type of device. For Android's downloadable apps, you can view and edit rich text area fields. However, for Android's mobile browser apps, you can only view rich text area fields; editing is not supported currently. For iOS's downloadable apps, you can view but not edit rich text area fields. However, for iOS's mobile browser apps, you can view and also edit rich text area fields. Finally, for both BlackBerry and Windows 8.1 mobile browser apps, you can neither view nor edit rich text area fields. Related lists in Salesforce1 Related lists in Salesforce1 are restricted and display the first four fields that are defined on the page layout for that object. The number of fields shown cannot be increased. If Chatter is enabled, users can also access feeds, people, groups, and Salesforce Files. When users are working with records in the full Salesforce app, it can take up to 15 days for this data to appear in the Recent section; thus, to make records appear under the Recent section sooner, ask users to pin them from their search results in the full Salesforce site. Salesforce1 administration You can manage your organization's access to Salesforce1 apps; there are two areas of administration: the mobile browser app that users can access by logging in to Salesforce from a supported mobile browser and the downloadable app that users can install from the App Store or Google Play. The upcoming sections describe the ways to control user access to each of these mobile apps. Salesforce1 mobile browser app access You can control whether users can access the Salesforce1 mobile browser app when they log into Salesforce from a mobile browser. To select or deselect this feature, navigate to Setup | Mobile Administration | Salesforce1 | Settings, as shown in the following screenshot: By selecting the Enable the Salesforce1 mobile browser app checkbox, all users are activated to access Salesforce1 from their mobile browsers. Deselecting this option turns off the mobile browser app, which means that users will automatically access the full Salesforce site from their mobile browser. By default, the mobile browser app is turned on in all Salesforce organizations. Salesforce1 desktop browser access Selecting the Enable the Salesforce1 mobile browser app checkbox, as described in the previous section, permits users who are activated to access Salesforce1 from their desktop browsers. Users can navigate to the Salesforce1 app within their desktop browser by appending “/one/one.app” to the end of the Salesforce URL. As an example, for the following Salesforce URL accessed from the server na10, you would enter the https://na10.salesforce.com/one/one.app desktop browser URL. Salesforce1 downloadable app access The Salesforce1 app is distributed as a managed package, and within Salesforce, it is implemented as a connected app. You might already see the Salesforce1 connected app in your list of installed apps as it might have been automatically installed in your organization. The list of included apps can change with each Salesforce release but, to simplify administration, each package is asynchronously installed in Salesforce organizations whenever any user in that organization first accesses Salesforce1. However, to manually install or reinstall the Salesforce1 package for connected apps, you can install it from the AppExchange. To view the details for the Salesforce1 app in the connected app settings, navigate to Setup | Manage Apps | Connected Apps. The apps that connect to your Salesforce organization are then listed as shown in the following screenshot: Salesforce1 notifications Notifications allow all users in your organization to receive mobile notifications in Salesforce1, for example, whenever they are mentioned in Chatter or whenever they receive approval requests. To activate mobile notifications, navigate to Setup | Mobile Administration | Notifications | Settings, as shown in the following screenshot: The settings for notifications can be set as follows: Enable in-app notifications: Set this option to keep users notified about relevant Salesforce activity while they are using Salesforce1. Enable push notifications: Set this option to keep users notified of relevant Salesforce activity when they are not using the Salesforce1 downloadable app. Include full content in push notifications: Keep this checkbox unchecked if you do not want users to receive full content in push notifications. This can prevent users from receiving potentially sensitive data that might be in comments, for example. If you set this option, a pop-up dialog appears, displaying terms and conditions where you must click on OK or Cancel. Salesforce1 branding This option allows you to customize the appearance of the Salesforce1 app so that it complies with any company branding requirements that might be in place. Salesforce1 branding is supported in downloadable apps' Version 5.2 or higher and also in the mobile browser app. To specify Salesforce1 branding, navigate to Setup | Mobile Administration | Salesforce1 | Branding, as shown in the following screenshot: Salesforce1 compact layouts In Salesforce1, compact layouts are used to display the key fields on a record and are specifically designed to view records on touchscreen mobile devices. As space is limited on mobile devices and quick recognition of records is important, the first four fields that you assign to a compact layout are displayed. If a mobile user does not have the required access to one of the first four fields that have been assigned to a compact layout, the next field, if more than four fields have been set on the layout, is used. If you are yet to create custom compact layouts, the records will be displayed using a read-only, predefined system default compact layout, and after you have created a custom compact layout, you can then set it as the primary compact layout for that object. As with the full Salesforce CRM site, if you have record types associated with an object, you can alter the primary compact layout assignment and assign specific compact layouts to different record types. You can also clone a compact layout from its detail page. The upcoming field types cannot be included on compact layouts: text area, long text area, rich text area, and multiselect picklists. Salesforce1 offline access In Salesforce1, the mechanism to handle offline access is determined by users' most recently used records. These records are cached for offline access; at the time of writing this, they are read-only. The cached data is encrypted and secured through persistent storage by Salesforce1's downloadable apps. Offline access is available in Salesforce1's downloadable apps Version 6.0 and higher and was first released in Summer 2014. Offline access is enabled by default when Salesforce1's downloadable app is installed. To manage these settings, navigate to Setup | Mobile Administration | Offline. Now, check or uncheck Enable Offline Sync for Salesforce1, as shown in the following screenshot: When offline access is enabled, data based on the objects is downloaded to each user's mobile device and presented in the Recent section of the Salesforce1 navigation menu and on the user's most recently viewed records. The data is encrypted and stored in a secure, persistent cache on the mobile device. Setting up Salesforce1 with the Salesforce1 Wizard The Salesforce1 Wizard simplifies the setting up of the Salesforce1 mobile app. The wizard offers a visual tour of the key setup steps and is useful if you are new to Salesforce1 or need to quickly set up the core Salesforce1 settings. The Salesforce1 Wizard guides you through the setting up of the following Salesforce1 configuration steps: Choose which items appear in the navigation menu Configure global actions Create a contact custom compact layout Optionally, invite users to start using the Salesforce1 app To access the Salesforce1 Wizard, navigate to Setup | Salesforce1 Setup. Now, click on Launch Quick Start Wizard within the Salesforce1 Setup page, as shown in the following screenshot: Upon clicking on the Let's Get Started section link (shown in the following screenshot), you will be presented with the Salesforce1 Setup visual tour, as shown in the next section. The Quick Start Wizard The Quick Start Wizard guides you through the minimum configuration steps required to set up Salesforce1. By clicking on the Launch Quick Start Wizard button, the process to complete the essential setup tasks for Salesforce1 is initiated and provides a step-by-step wizard guide. The five steps are: Customize the Navigation Menu: This step results in the setup of the navigation menu for all users in your organization. To reorder items, drag them up and down. To remove items, drag them to the Available Items list, as shown in the following screenshot: Arrange Global Actions: Global actions provide users with quick access to Salesforce functions and in this step, you will choose and arrange the Salesforce1 global actions, as shown in the following screenshot: Actions might might have a different appearance, depending upon your version of Salesforce1. Create a Custom Compact Layout for Contacts: Compact layouts are used to show the key fields on a record in the highlights area at the top of the record detail. In this step, you are able to create a custom compact layout for contacts to set, for example, a contact's name, e-mail, and phone number, as shown in the following screenshot: However, after you have completed the Quick Start Wizard, you can create compact layouts for other objects as required. Review: In this step, you are given the chance to preview the changes to verify the results of the changes, as shown in the following screenshot: The review step screen gives you a live preview that uses your current access as the logged-in user. Send Invitations: This is the final step of the Quick Start Wizard, which will provide you with a basic setup of Salesforce1 and allow you to get feedback on what you have implemented. In this step, you can invite your users to start using the Salesforce1 app, as shown in the following screenshot: This step can be skipped and you can always send invitations later from the Salesforce1 setup page. You can also implement additional options to customize the app, such as incorporating your own branding. Differences between Salesforce1 and the full Salesforce CRM browser app In the Winter 2015 release and at the time of writing this, Salesforce1 does not have all of the features of the full Salesforce CRM site; moreover, in some areas, it includes functionality that is not available in, or is different from, the complete Salesforce site. As an example, on the full Salesforce CRM site, compact layouts determine which fields appear in the Chatter feed item and which appear after a user creates a record via a publisher action. However, compact layouts in Salesforce1 are used to display the key fields on a record. For details about the features that differ between the full Salesforce CRM site and Salesforce1, refer to Salesforce1 Limits and Differences from the Full Salesforce Site within the Salesforce Help menu sections. Summary In this article, we looked at ways in which mobile has become the new normal way to stay connected in both our personal and professional lives. Salesforce has recognized this well; we are all spending time being connected to the cloud and using business applications. However, instead of sitting at a desk, users are often on the go. To try and help their customers become successful businesses of this mobile-first world, Salesforce has produced mobile solutions that can help user get things done regardless of where they are and what they are doing. We looked at SalesforceA, which is an admin specific app that can help you manage users and monitor the status of Salesforce while on the move. We discussed Salesforce Touch, which is being replaced with Salesforce1, and we also spoke about the features and benefits of Salesforce1, which is available as a downloadable app and a browser app. Resources for Article: Further resources on this subject: Customization in Microsoft Dynamics CRM [Article] Getting Started with Microsoft Dynamics CRM 2013 Marketing [Article] Diagnostic leveraging of the Accelerated POC with the CRM Online service [Article]

In this article by Jordan Krause, author of the book Windows Server 2012 R2 Administrator Cookbook, we will see how Windows Server 2012 R2 by Microsoft brings a whole new way of looking at remote access. Companies have historically relied on third-party tools to connect remote users into the network, such as traditional and SSL VPN provided by appliances from large networking vendors. I'm here to tell you those days are gone. Those of us running Microsoft-centric shops can now rely on Microsoft technologies to connect our remote workforce. Better yet is that these technologies are included with the Server 2012 R2 operating system, and have functionality that is much improved over anything that a traditional VPN can provide. Regular VPN does still have a place in the remote access space, and the great news is that you can also provide it with Server 2012 R2. Our primary focus for this article will be DirectAccess (DA). DA is kind of like automatic VPN. There is nothing the user needs to do in order to be connected to work. Whenever they are on the Internet, they are also connected automatically to the corporate network. DirectAccess is an amazing way to have your Windows 7 and Windows 8 domain joined systems connected back to the network for data access and for management of those traveling machines. DirectAccess has actually been around since 2008, but the first version came with some steep infrastructure requirements and was not widely used. Server 2012 R2 brings a whole new set of advantages and makes implementation much easier than in the past. I still find many server and networking admins who have never heard of DirectAccess, so let's spend some time together exploring some of the common tasks associated with it. In this article, we will cover the following recipes: Configuring DirectAccess, VPN, or a combination of the two Pre-staging Group Policy Objects (GPOs) to be used by DirectAccess Enhancing the security of DirectAccess by requiring certificate authentication Building your Network Location Server (NLS) on its own system  (For more resources related to this topic, see here.) There are two "flavors" of remote access available in Windows Server 2012 R2. The most common way to implement the Remote Access role is to provide DirectAccess for your Windows 7 and Windows 8 domain joined client computers, and VPN for the rest. The DirectAccess machines are typically your company-owned corporate assets. One of the primary reasons that DirectAccess is usually only for company assets is that the client machines must be joined to your domain, because the DirectAccess configuration settings are brought down to the client through a GPO. I doubt you want home and personal computers joining your domain. VPN is therefore used for down level clients such as Windows XP, and for home and personal devices that want to access the network. Since this is a traditional VPN listener with all regular protocols available such as PPTP, L2TP, SSTP, it can even work to connect devices such as smartphones. There is a third function available within the Server 2012 R2 Remote Access role, called the Web Application Proxy ( WAP ). This function is not used for connecting remote computers fully into the network as DirectAccess and VPN are; rather, WAP is used for publishing internal web resources out to the internet. For example, if you are running Exchange and Lync Server inside your network and want to publish access to these web-based resources to the internet for external users to connect to, WAP would be a mechanism that could publish access to these resources. The term for publishing out to the internet like this is Reverse Proxy, and WAP can act as such. It can also behave as an ADFS Proxy. For further information on the WAP role, please visit: http://technet.microsoft.com/en-us/library/dn584107.aspx One of the most confusing parts about setting up DirectAccess is that there are many different ways to do it. Some are good ideas, while others are not. Before we get rolling with recipes, we are going to cover a series of questions and answers to help guide you toward a successful DA deployment. The first question that always presents itself when setting up DA is "How do I assign IP addresses to my DirectAccess server?". This is quite a loaded question, because the answer depends on how you plan to implement DA, which features you plan to utilize, and even upon how secure you believe your DirectAccess server to be. Let me ask you some questions, pose potential answers to those questions, and discuss the effects of making each decision. DirectAccess Planning Q&A Which client operating systems can connect using DirectAccess? Answer: Windows 7 Ultimate, Windows 7 Enterprise, and Windows 8.x Enterprise. You'll notice that the Professional SKU is missing from this list. That is correct, Windows 7 and Windows 8 Pro do not contain the DirectAccess connectivity components. Yes, this does mean that Surface Pro tablets cannot utilize DirectAccess out of the box. However, I have seen many companies now install Windows 8 Enterprise onto their Surface tablets, effectively turning them into "Surface Enterprises." This works fine and does indeed enable them to be DirectAccess clients. In fact, I am currently typing this text on a DirectAccess-connected Surface "Pro turned Enterprise" tablet. Do I need one or two NICs on my DirectAccess server? Answer: Technically, you could set it up either way. In practice however, it really is designed for dual-NIC implementation. Single NIC DirectAccess works okay sometimes to establish a proof-of-concept to test out the technology. But I have seen too many problems with single NIC implementation in the field to ever recommend it for production use. Stick with two network cards, one facing the internal network and one facing the Internet. Do my DirectAccess servers have to be joined to the domain? Answer: Yes. Does DirectAccess have site-to-site failover capabilities? Answer: Yes, though only Windows 8.x client computers can take advantage of it. This functionality is called Multi-Site DirectAccess. Multiple DA servers that are spread out geographically can be joined together in a multi-site array. Windows 8 client computers keep track of each individual entry point and are able to swing between them as needed or at user preference. Windows 7 clients do not have this capability and will always connect through their primary site. What are these things called 6to4, Teredo, and IP-HTTPS I have seen in the Microsoft documentation? Answer: 6to4, Teredo, and IP-HTTPS are all IPv6 transition tunneling protocols. All DirectAccess packets that are moving across the internet between DA client and DA server are IPv6 packets. If your internal network is IPv4, then when those packets reach the DirectAccess server they get turned down into IPv4 packets, by some special components called DNS64 and NAT64. While these functions handle the translation of packets from IPv6 into IPv4 when necessary inside the corporate network, the key point here is that all DirectAccess packets that are traveling over the Internet part of the connection are always IPv6. Since the majority of the Internet is still IPv4, this means that we must tunnel those IPv6 packets inside something to get them across the Internet. That is the job of 6to4, Teredo, and IP-HTTPS. 6to4 encapsulates IPv6 packets into IPv4 headers and shuttles them around the internet using protocol 41. Teredo similarly encapsulates IPv6 packets inside IPv4 headers, but then uses UDP port 3544 to transport them. IP-HTTPS encapsulates IPv6 inside IPv4 and then inside HTTP encrypted with TLS, essentially creating an HTTPS stream across the Internet. This, like any HTTPS traffic, utilizes TCP port 443. The DirectAccess traffic traveling inside either kind of tunnel is always encrypted, since DirectAccess itself is protected by IPsec. Do I want to enable my clients to connect using Teredo? Answer: Most of the time, the answer here is yes. Probably the biggest factor that weighs on this decision is whether or not you are still running Windows 7 clients. When Teredo is enabled in an environment, this gives the client computers an opportunity to connect using Teredo, rather than all clients connecting in over the IP-HTTPS protocol. IP-HTTPS is sort of the "catchall" for connections, but Teredo will be preferred by clients if it is available. For Windows 7 clients, Teredo is quite a bit faster than IP-HTTPS. So enabling Teredo on the server side means your Windows 7 clients (the ones connecting via Teredo) will have quicker response times, and the load on your DirectAccess server will be lessened. This is because Windows 7 clients who are connecting over IP-HTTPS are encrypting all of the traffic twice. This also means that the DA server is encrypting/decrypting everything that comes and goes twice. In Windows 8, there is an enhancement that brings IP-HTTPS performance almost on par with Teredo, and so environments that are fully cut over to Windows 8 will receive less benefit from the extra work that goes into making sure Teredo works. Can I place my DirectAccess server behind a NAT? Answer: Yes, though there is a downside. Teredo cannot work if the DirectAccess server is sitting behind a NAT. For Teredo to be available, the DA server must have an External NIC that has two consecutive public IP addresses. True public addresses. If you place your DA server behind any kind of NAT, Teredo will not be available and all clients will connect using the IP-HTTPS protocol. Again, if you are using Windows 7 clients, this will decrease their speed and increase the load on your DirectAccess server. How many IP addresses do I need on a standalone DirectAccess server? Answer: I am going to leave single NIC implementation out of this answer since I don't recommend it anyway. For scenarios where you are sitting the External NIC behind a NAT or, for any other reason, are limiting your DA to IP-HTTPS only, then we need one external address and one internal address. The external address can be a true public address or a private NATed DMZ address. Same with the internal; it could be a true internal IP or a DMZ IP. Make sure both NICs are not plugged into the same DMZ, however. For a better installation scenario that allows Teredo connections to be possible, you would need two consecutive public IP addresses on the External NIC and a single internal IP on the Internal NIC. This internal IP could be either true internal or DMZ. But the public IPs would really have to be public for Teredo to work. Do I need an internal PKI? Answer: Maybe. If you want to connect Windows 7 clients, then the answer is yes. If you are completely Windows 8, then technically you do not need internal PKI. But you really should use it anyway. Using an internal PKI, which can be a single, simple Windows CA server, increases the security of your DirectAccess infrastructure. You'll find out during this article just how easy it is to require certificates as part of the tunnel building authentication process. Configuring DirectAccess, VPN, or a combination of the two Now that we have some general ideas about how we want to implement our remote access technologies, where do we begin? Most services that you want to run on a Windows Server begin with a role installation, but the implementation of remote access begins before that. Let's walk through the process of taking a new server and turning it into a Microsoft Remote Access server. Getting ready All of our work will be accomplished on a new Windows Server 2012 R2. We are taking the two-NIC approach to networking, and so we have two NICs installed on this server. The Internal NIC is plugged into the corporate network and the External NIC is plugged into the Internet for the sake of simplicity. The External NIC could just as well be plugged into a DMZ. How to do it... Follow these steps to turn your new server into a Remote Access server: Assign IP addresses to your server. Remember, the most important part is making sure that the Default Gateway goes on the External NIC only. Join the new server to your domain. Install an SSL certificate onto your DirectAccess server that you plan to use for the IP-HTTPS listener. This is typically a certificate purchased from a public CA. If you're planning to use client certificates for authentication, make sure to pull down a copy of the certificate to your DirectAccess server. You want to make sure certificates are in place before you start with the configuration of DirectAccess. This way the wizards will be able to automatically pull in information about those certificates in the first run. If you don't, DA will set itself up to use self-signed certificates, which are a security no-no. Use Server Manager to install the Remote Access role. You should only do this after completing the steps listed earlier. If you plan to load balance multiple DirectAccess servers together at a later time, make sure to also install the feature called Network Load Balancing . After selecting your role and feature, you will be asked which Remote Access role services you want to install. For our purposes in getting the remote workforce connected back into the corporate network, we want to choose DirectAccess and VPN (RAS) .  Now that the role has been successfully installed, you will see a yellow exclamation mark notification near the top of Server Manager indicating that you have some Post-deployment Configuration that needs to be done. Do not click on Open the Getting Started Wizard ! Unfortunately, Server Manager leads you to believe that launching the Getting Started Wizard (GSW) is the logical next step. However, using the GSW as the mechanism for configuring your DirectAccess settings is kind of like roasting a marshmallow with a pair of tweezers. In order to ensure you have the full range of options available to you as you configure your remote access settings, and that you don't get burned later, make sure to launch the configuration this way: Click on the Tools menu from inside Server Manager and launch the Remote Access Management Console . In the left window pane, click on Configuration | DirectAccess and VPN . Click on the second link, the one that says Run the Remote Access Setup Wizard . Please note that once again the top option is to run that pesky Getting Started Wizard. Don't do it! I'll explain why in the How it works… section of this recipe. Now you have a choice that you will have to answer for yourself. Are you configuring only DirectAccess, only VPN, or a combination of the two? Simply click on the option that you want to deploy. Following your choice, you will see a series of steps (steps 1 through 4) that need to be accomplished. This series of mini-wizards will guide you through the remainder of the DirectAccess and VPN particulars. This recipe isn't large enough to cover every specific option included in those wizards, but at least you now know the correct way to bring a DirectAccess/VPN server into operation. How it works... The remote access technologies included in Server 2012 R2 have great functionality, but their initial configuration can be confusing. Following the procedure listed in this recipe will set you on the right path to be successful in your deployment, and prevent you from running into issues down the road. The reason that I absolutely recommend you stay away from using the "shortcut" deployment method provided by the Getting Started Wizard is twofold: GSW skips a lot of options as it sets up DirectAccess, so you don't really have any understanding of how it works after finishing. You may have DA up and running, but have no idea how it's authenticating or working under the hood. This holds so much potential for problems later, should anything suddenly stop working. GSW employs a number of bad security practices in order to save time and effort in the setup process. For example, using the GSW usually means that your DirectAccess server will be authenticating users without client certificates, which is not a best practice. Also, it will co-host something called the NLS website on itself, which is also not a best practice. Those who utilize the GSW to configure DirectAccess will find that their GPO, which contains the client connectivity settings, will be security-filtered to the Domain Computers group. Even though it also contains a WMI filter that is supposed to limit that policy application to mobile hardware such as laptops, this is a terribly scary thing to see inside GPO filtering settings. You probably don't want all of your laptops to immediately start getting DA connectivity settings, but that is exactly what the GSW does for you. Perhaps worst, the GSW will create and make use of self-signed SSL certificates to validate its web traffic, even the traffic coming in from the Internet! This is a terrible practice and is the number one reason that should convince you that clicking on the Getting Started Wizard is not in your best interests. Pre-staging Group Policy Objects (GPOs) to be used by DirectAccess One of the great things about DirectAccess is that all of the connectivity settings the client computers need in order to connect are contained within a Group Policy Object (GPO). This means that you can turn new client computers into DirectAccess-connected clients without ever touching that system. Once configured properly, all you need to do is add the new computer account to an Active Directory security group, and during the next automatic Group Policy refresh cycle (usually within 90 minutes), that new laptop will be connecting via DirectAccess whenever outside the corporate network. You can certainly choose not to pre-stage anything with the GPOs and DirectAccess will still work. When you get to the end of the DA configuration wizards, it will inform you that two new GPOs are about to be created inside Active Directory. One GPO is used to contain the DirectAccess server settings and the other GPO is used to contain the DirectAccess client settings. If you allow the wizard to handle the generation of these GPOs, it will create them, link them, filter them, and populate them with settings automatically. About half of the time I see folks do it this way and they are forever happy with letting the wizard manage those GPOs now and in the future. The other half of the time, it is desired that we maintain a little more personal control over the GPOs. If you are setting up a new DA environment but your credentials don't have permission to create GPOs, the wizard is not going to be able to create them either. In this case, you will need to work with someone on your Active Directory team to get them created. Another reason to manage the GPOs manually is to have better control over placement of these policies. When you let the DirectAccess wizard create the GPOs, it will link them to the top level of your domain. It also sets Security Filtering on those GPOs so they are not going to be applied to everything in your domain, but when you open up the Group Policy Management Console you will always see those DirectAccess policies listed right up there at the top level of the domain. Sometimes this is simply not desirable. So for this reason also, you may want to choose to create and manage the GPOs by hand, so that we can secure placement and links where we specifically want them to be located. The key factors here are to make sure your DirectAccess Server Settings GPO applies to only the DirectAccess server or servers in your environment. And that the DirectAccess Client Settings GPO applies to only the DA client computers that you plan to enable in your network. The best practice here is to specify this GPO to only apply to a specific Active Directory security group so that you have full control over which computer accounts are in that group. I have seen some folks do it based only on the OU links and include whole OUs in the filtering for the clients GPO (foregoing the use of an AD group at all), but doing it this way makes it quite a bit more difficult to add or remove machines from the access list in the future. Requiring certificates as part of your DirectAccess tunnel authentication process is a good idea in any environment. It makes the solution more secure, and enables advanced functionality. The primary driver for most companies to require these certificates is the enablement of Windows 7 clients to connect via DirectAccess, but I suggest that anyone using DirectAccess in any capacity make use of these certs. They are simple to deploy, easy to configure, and give you some extra peace of mind that only computers who have a certificate issued directly to them from your own internal CA server are going to be able to connect through your DirectAccess entry point. Getting ready While the DirectAccess wizards themselves are run from the DirectAccess server, our work with this recipe is not. The Group Policy settings that we will be configuring are all accomplished within Active Directory, and we will be doing the work from a Domain Controller in our environment. How to do it... To pre-stage Group Policy Objects (GPOs) for use with DirectAccess: On your Domain Controller, launch the Group Policy Management Console . Expand Forest | Domains | Your Domain Name . There should be a listing here called Group Policy Object . Right-click on that and choose New . Name your new GPO something like DirectAccess Server Settings. Click on the new DirectAccess Server Settings GPO and it should open up automatically to the Scope tab. We need to adjust the Security Filtering section so that this GPO only applies to our DirectAccess server. This is a critical step for each GPO to ensure the settings that are going to be placed here do not get applied to the wrong computers. Remove Authenticated Users that is prepopulated in that list. The list should now be empty. Click the Add… button and search for the computer account of your DirectAccess server. Mine is called RA-01. By default this window will only search user accounts, so you will need to adjust Object Types to include Computers before it will allow you to add your server into this filtering list. Your Security Filtering list should now look like this:  Now click on the Details tab of your GPO. Change the GPO Status to be User configuration settings disabled . We do this because our GPO is only going to contain computer-level settings, nothing at the user level. The last thing to do is link your GPO to an appropriate container. Since we have Security Filtering enabled, our GPO is only ever going to apply its settings to the RA-01 server; however, without creating a link, the GPO will not even attempt to apply itself to anything. My RA-01 server is sitting inside the OU called Remote Access Servers . So I will right-click on my Remote Access Servers OU and choose Link an Existing GPO… .  Choose the new DirectAccess Server Settings from the list of available GPOs and click on the OK button. This creates the link and puts the GPO into action. Since there are not yet any settings inside the GPO, it won't actually make any changes on the server. The DirectAccess configuration wizards take care of populating the GPO with the settings that are needed. Now we simply need to rinse and repeat all of these steps to create another GPO, something like DirectAccess Client Settings . You want to set up the client settings GPO in the same way. Make sure that it is filtering to only the Active Directory Security Group that you created to contain your DirectAccess client computers. And make sure to link it to an appropriate container that will include those computer accounts. So maybe your clients GPO will look something like this:  How it works... Creating GPOs in Active Directory is a simple enough task, but it is critical that you configure the Links and Security Filtering correctly. If you do not take care to ensure that these DirectAccess connection settings are only going to apply to the machines that actually need the settings, you could create a world of trouble by internal servers getting remote access connection settings and cause them issues with connection while inside the network. Enhancing the security of DirectAccess by requiring certificate authentication When a DirectAccess client computer builds its IPsec tunnels back to the corporate network, it has the ability to require a certificate as part of that authentication process. In earlier versions of DirectAccess, the one in Server 2008 R2 and the one provided by Unified Access Gateway ( UAG ), these certificates were required in order to make DirectAccess work. Setting up the certificates really isn't a big deal at all; as long as there is a CA server in your network you are already prepared to issue the certs needed at no cost. Unfortunately, though, there must have been enough complaints back to Microsoft in order for them to make these certificates "recommended" instead of "required" and they created a new mechanism in Windows 8 and Server 2012 called KerberosProxy that can be used to authenticate the tunnels instead. This allows the DirectAccess tunnels to build without the computer certificate, making that authentication process less secure. I'm here to strongly recommend that you still utilize certificates in your installs! They are not difficult to set up, and using them makes your tunnel authentication stronger. Further, many of you may not have a choice and will still be required to install these certificates. Only simple DirectAccess scenarios that are all Windows 8 on the client side can get away with the shortcut method of foregoing certs. Anybody who still wants to connect Windows 7 via DirectAccess will need to use certificates on all of their client computers, both Windows 7 and Windows 8. In addition to Windows 7 access, anyone who intends to use the advanced features of DirectAccess such as load balancing, multi-site, or two-factor authentication will also need to utilize these certificates. With any of these scenarios, certificates become a requirement again, not a recommendation. In my experience, almost everyone still has Windows 7 clients that would benefit from being DirectAccess connected, and it's always a good idea to make your DA environment redundant by having load balanced servers. This further emphasizes the point that you should just set up certificate authentication right out of the gate, whether or not you need it initially. You might decide to make a change later that would require certificates and it would be easier to have them installed from the get-go rather than trying to incorporate them later into a running DA environment. Getting ready In order to distribute certificates, you will need a CA server running in your network. Once certificates are distributed to the appropriate places, the rest of our work will be accomplished from our Server 2012 R2 DirectAccess server. How to do it... Follow these steps to make use of certificates as part of the DirectAccess tunnel authentication process: The first thing that you need to do is distribute certificates to your DirectAccess servers and all DirectAccess client computers. The easiest way to do this is by using the built-in Computer template provided by default in a Windows CA server. If you desire to build a custom certificate template for this purpose, you can certainly do so. I recommend that you duplicate the Computer template and build it from there. Whenever I create a custom template for use with DirectAccess, I try to make sure that it meets the following criterias: The Subject Name of the certificate should match the Common Name of the computer (which is also the FQDN of the computer). The Subject Alternative Name ( SAN ) of the certificate should match the DNS Name of the computer (which is also the FQDN of the computer). The certificate should serve the Intended Purposes of both Client Authentication and Server Authentication . You can issue the certificates manually using Microsoft Management Console (MMC). Otherwise, you can lessen your hands-on administrative duties by enabling Autoenrollment. Now that we have certificates distributed to our DirectAccess clients and servers, log in to your primary DirectAccess server and open up the Remote Access Management Console . Click on Configuration in the top-left corner. You should now see steps 1 through 4 listed. Click Edit… listed under Step 2 . Now you can either click Next twice or click on the word Authentication to jump directly to the authentication screen. Check the box that says Use computer certificates . Now we have to specify the Certification Authority server that issued our client certificates. If you used an intermediary CA to issue your certs, make sure to check the appropriate checkbox. Otherwise, most of the time, certificates are issued from a root CA and in this case you would simply click on the Browse… button and look for your CA in the list. This screen is sometimes confusing because people expect to have to choose the certificate itself from the list. This is not the case. What you are actually choosing from this list is the Certificate Authority server that issued the certificates. Make any other appropriate selections on the Authentication screen. For example, many times when we require client certificates for authentication, it is because we have Windows 7 computers that we want to connect via DirectAccess. If that is the case for you, select the checkbox for Enable Windows 7 client computers to connect via DirectAccess .  How it works... Requiring certificates as part of your DirectAccess tunnel authentication process is a good idea in any environment. It makes the solution more secure, and enables advanced functionality. The primary driver for most companies to require these certificates is the enablement of Windows 7 clients to connect via DirectAccess, but I suggest that anyone using DirectAccess in any capacity make use of these certs. They are simple to deploy, easy to configure, and give you some extra peace of mind that only computers who have a certificate issued directly to them from your own internal CA server are going to be able to connect through your DirectAccess entry point. Building your Network Location Server (NLS) on its own system If you zipped through the default settings when configuring DirectAccess, or worse used the Getting Started Wizard, chances are that your Network Location Server ( NLS ) is running right on the DirectAccess server itself. This is not the recommended method for using NLS, it really should be running on a separate web server. In fact, if you later want to do something more advanced such as setting up load balanced DirectAccess servers, you're going to have to move NLS off onto a different server anyway. So you might as well do it right the first time. NLS is a very simple requirement, yet a critical one. It is just a website, it doesn't matter what content the site has, and it only has to run inside your network. Nothing has to be externally available. In fact, nothing should be externally available, because you only want this site being accessed internally. This NLS website is a large part of the mechanism by which DirectAccess client computers figure out when they are inside the office and when they are outside. If they can see the NLS website, they know they are inside the network and will disable DirectAccess name resolution, effectively turning off DA. If they do not see the NLS website, they will assume they are outside the corporate network and enable DirectAccess name resolution. There are two gotchas with setting up an NLS website: The first is that it must be HTTPS, so it does need a valid SSL certificate. Since this website is only running inside the network and being accessed from domain-joined computers, this SSL certificate can easily be one that has been issued from your internal CA server. So no cost associated there. The second catch that I have encountered a number of times is that for some reason the default IIS splash screen page doesn't make for a very good NLS website. If you set up a standard IIS web server and use the default site as NLS, sometimes it works to validate the connections and sometimes it doesn't. Given that, I always set up a specific site that I create myself, just to be on the safe side. So let's work together to follow the exact process I always take when setting up NLS websites in a new DirectAccess environment. Getting ready Our NLS website will be hosted on an IIS server we have that runs Server 2012 R2. Most of the work will be accomplished from this web server, but we will also be creating a DNS record and will utilize a Domain Controller for that task. How to do it... Let's work together to set up our new Network Location Server website: First decide on an internal DNS name to use for this website and set it up in DNS of your domain. I am going to use nls.mydomain.local and am creating a regular Host (A) record that points nls.mydomain.local at the IP address of my web server. Now log in to that web server and let's create some simple content for this new website. Create a new folder called C:NLS. Inside your new folder, create a new Default.htm file. Edit this file and throw some simple text in there. I usually say something like This is the NLS website used by DirectAccess. Please do not delete or modify me!.  Remember, this needs to be an HTTPS website, so before we try setting up the actual website, we should acquire the SSL certificate that we need to use with this site. Since this certificate is coming from my internal CA server, I'm going to open up MMC on my web server to accomplish this task. Once MMC is opened, snap-in the Certificates module. Make sure to choose Computer account and then Local computer when it prompts you for which certificate store you want to open. Expand Certificates (Local Computer) | Personal | Certificates . Right-click on this Certificates folder and choose All Tasks | Request New Certificate… . Click Next twice and you should see your list of certificate templates that are available on your internal CA server. If you do not see one that looks appropriate for requesting a website certificate, you may need to check over the settings on your CA server to make sure the correct templates are configured for issuing. My template is called Custom Web Server . Since this is a web server certificate, there is some additional information that I need to provide in my request in order to successfully issue a certificate. So I go ahead and click on that link that says More information is required to enroll for this certificate. Click here to configure settings. .  Drop-down the Subject name | Type menu and choose the option Common name . Enter a common name for our website into the Value field, which in my case is nls.mydomain.local. Click the Add button and your CN should move over to the right side of the screen like this:  Click on OK then click on the Enroll button. You should now have an SSL certificate sitting in your certificates store that can be used to authenticate traffic moving to our nls.mydomain.local name. Open up Internet Information Services (IIS) Manager , and browse to the Sites folder. Go ahead and remove the default website that IIS automatically set up, so that we can create our own NLS website without any fear of conflict. Click on the Add Website… action. Populate the information as shown in the following screenshot. Make sure to choose your own IP address and SSL certificate from the lists, of course:  Click the OK button and you now have an NLS website running successfully in your network. You should be able to open up a browser on a client computer sitting inside the network and successfully browse to https://nls.mydomain.local. How it works... In this recipe, we configured a basic Network Location Server website for use with our DirectAccess environment. This site will do exactly what we need it to when our DA client computers try to validate whether they are inside or outside the corporate network. While this recipe meets our requirements for NLS, and in fact puts us into a good practice of installing DirectAccess with NLS being hosted on its own web server, there is yet another step you could take to make it even better. Currently this web server is a single point of failure for NLS. If this web server goes down or has a problem, we would have DirectAccess client computers inside the office who would think they are outside, and they would have some major name resolution problems until we sorted out the NLS problem. Given that, it is a great idea to make NLS redundant. You could cluster servers together, use Microsoft Network Load Balancing ( NLB ), or even use some kind of hardware load balancer if you have one available in your network. This way you could run the same NLS website on multiple web servers and know that your clients will still work properly in the event of a web server failure. Summary This article encourages you to use Windows Server 2012 R2 as the connectivity platform that brings your remote computers into the corporate network. We discussed DirectAccess and VPN in this article. We also saw how to configure DirectAccess and VPN, and how to secure DirectAccess using certificate authentication. Resources for Article: Further resources on this subject: Cross-premise Connectivity [article] Setting Up and Managing E-mails and Batch Processing [article] Upgrading from Previous Versions [article]

In this article by Christopher Ilacqua, Henric Cronström, and James Richardson, authors of the book Learning Qlik® Sense, we will look at the evolving requirements that compel organizations to readdress how they deliver business intelligence and support data-driven decision-making. This is important as it supplies some of the reasons as to why Qlik® Sense is relevant and important to their success. The purpose of covering these factors is so that you can consider and plan for them in your organization. Among other things, in this article, we will cover the following topics: The ongoing data explosion The rise of in-memory processing Barrierless BI through Human-Computer Interaction The consumerization of BI and the rise of self-service The use of information as an asset The changing role of IT (For more resources related to this topic, see here.) Evolving market factors Technologies are developed and evolved in response to the needs of the environment they are created and used within. The most successful new technologies anticipate upcoming changes in order to help people take advantage of altered circumstances or reimagine how things are done. Any market is defined by both the suppliers—in this case, Qlik®—and the buyers, that is, the people who want to get more use and value from their information. Buyers' wants and needs are driven by a variety of macro and micro factors, and these are always in flux in some markets more than others. This is obviously and apparently the case in the world of data, BI, and analytics, which has been changing at a great pace due to a number of factors discussed further in the rest of this article. Qlik Sense has been designed to be the means through which organizations and the people that are a part of them thrive in a changed environment. Big, big, and even bigger data A key factor is that there's simply much more data in many forms to analyze than before. We're in the middle of an ongoing, accelerating data boom. According to Science Daily, 90 percent of the world's data was generated over the past two years. The fact is that with technologies such as Hadoop and NoSQL databases, we now have unprecedented access to cost-effective data storage. With vast amounts of data now storable and available for analysis, people need a way to sort the signal from the noise. People from a wider variety of roles—not all of them BI users or business analysts—are demanding better, greater access to data, regardless of where it comes from. Qlik Sense's fundamental design centers on bringing varied data together for exploration in an easy and powerful way. The slow spinning down of the disk At the same time, we are seeing a shift in how computation occurs and potentially, how information is managed. Fundamentals of the computing architectures that we've used for decades, the spinning disk and moving read head, are becoming outmoded. This means storing and accessing data has been around since Edison invented the cylinder phonograph in 1877. It's about time this changed. This technology has served us very well; it was elegant and reliable, but it has limitations. Speed limitations primarily. Fundamentals that we take for granted today in BI, such as relational and multidimensional storage models, were built around these limitations. So were our IT skills, whether we realized it at the time. With the use of in-memory processing and 64-bit addressable memory spaces, these limitations are gone! This means a complete change in how we think about analysis. Processing data in memory means we can do analysis that was impractical or impossible before with the old approach. With in-memory computing, analysis that would've taken days before, now takes just seconds (or much less). However, why does it matter? Because it allows us to use the time more effectively; after all, time is the most finite resource of all. In-memory computing enables us to ask more questions, test more scenarios, do more experiments, debunk more hypotheses, explore more data, and run more simulations in the short window available to us. For IT, it means no longer trying to second-guess what users will do months or years in advance and trying to premodel it in order to achieve acceptable response times. People hate watching the hourglass spin. Qlik Sense's predecessor QlikView® was built on the exploitation of in-memory processing; Qlik Sense has it at its core too. Ubiquitous computing and the Internet of Things You may know that more than a billion people use Facebook, but did you know that the majority of those people do so from a mobile device? The growth in the number of devices connected to the Internet is absolutely astonishing. According to Cisco's Zettabyte Era report, Internet traffic from wireless devices will exceed traffic from wired devices in 2014. If we were writing this article even as recently as a year ago, we'd probably be talking about mobile BI as a separate thing from desktop or laptop delivered analytics. The fact of the matter is that we've quickly gone beyond that. For many people now, the most common way to use technology is on a mobile device, and they expect the kind of experience they've become used to on their iOS or Android device to be mirrored in complex software, such as the technology they use for visual discovery and analytics. From its inception, Qlik Sense has had mobile usage in the center of its design ethos. It's the first data discovery software to be built for mobiles, and that's evident in how it uses HTML5 to automatically render output for the device being used, whatever it is. Plug in a laptop running Qlik Sense to a 70-inch OLED TV and the visual output is resized and re-expressed to optimize the new form factor. So mobile is the new normal. This may be astonishing but it's just the beginning. Mobile technology isn't just a medium to deliver information to people, but an acceleration of data production for analysis too. By 2020, pretty much everyone and an increasing number of things will be connected to the Internet. There are 7 billion people on the planet today. Intel predicts that by 2020, more than 31 billion devices will be connected to the Internet. So, that's not just devices used by people directly to consume or share information. More and more things will be put online and communicate their state: cars, fridges, lampposts, shoes, rubbish bins, pets, plants, heating systems—you name it. These devices will generate a huge amount of data from sensors that monitor all kinds of measurable attributes: temperature, velocity, direction, orientation, and time. This means an increasing opportunity to understand a huge gamut of data, but without the right technology and approaches it will be complex to analyze what is going on. Old methods of analysis won't work, as they don't move quickly enough. The variety and volume of information that can be analyzed will explode at an exponential rate. The rise of this type of big data makes us redefine how we build, deliver, and even promote analytics. It is an opportunity for those organizations that can exploit it through analysis; this can sort the signals from the noise and make sense of the patterns in the data. Qlik Sense is designed as just such a signal booster; it takes how users can zoom and pan through information too large for them to easily understand the product. Unbound Human-Computer Interaction We touched on the boundary between the computing power and the humans using it in the previous section. Increasingly, we're removing barriers between humans and technology. Take the rise of touch devices. Users don't want to just view data presented to them in a static form. Instead, they want to "feel" the data and interact with it. The same is increasingly true of BI. The adoption of BI tools has been too low because the technology has been hard to use. Adoption has been low because in the past BI tools often required people to conform to the tool's way of working, rather than reflecting the user's way of thinking. The aspiration for Qlik Sense (when part of the QlikView.Next project) was that the software should be both "gorgeous and genius". The genius part obviously refers to the built-in intelligence, the smarts, the software will have. The gorgeous part is misunderstood or at least oversimplified. Yes, it means cosmetically attractive (which is important) but much more importantly, it means enjoyable to use and experience. In other words, Qlik Sense should never be jarring to users but seamless, perhaps almost transparent to them, inducing a state of mental flow that encourages thinking about the question being considered rather than the tool used to answer it. The aim was to be of most value to people. Qlik Sense will empower users to explore their data and uncover hidden insights, naturally. Evolving customer requirements It is not only the external market drivers that impact how we use information. Our organizations and the people that work within them are also changing in their attitude towards technology, how they express ideas through data, and how increasingly they make use of data as a competitive weapon. Consumerization of BI and the rise of self-service The consumerization of any technology space is all about how enterprises are affected by, and can take advantage of, new technologies and models that originate and develop in the consumer marker, rather than in the enterprise IT sector. The reality is that individuals react quicker than enterprises to changes in technology. As such, consumerization cannot be stopped, nor is it something to be adopted. It can be embraced. While it's not viable to build a BI strategy around consumerization alone, its impact must be considered. Consumerization makes itself felt in three areas: Technology: Most investment in innovation occurs in the consumer space first, with enterprise vendors incorporating consumer-derived features after the fact. (Think about how vendors added the browser as a UI for business software applications.) Economics: Consumer offerings are often less expensive or free (to try) with a low barrier of entry. This drives prices down, including enterprise sectors, and alters selection behavior. People: Demographics, which is the flow of Millennial Generation into the workplace, and the blurring of home/work boundaries and roles, which may be seen from a traditional IT perspective as rogue users, with demands to BYOPC or device. In line with consumerization, BI users want to be able to pick up and just use the technology to create and share engaging solutions; they don't want to read the manual. This places a high degree of importance on the Human-Computer Interaction (HCI) aspects of a BI product (refer to the preceding list) and governed access to information and deployment design. Add mobility to this and you get a brand new sourcing and adoption dynamic in BI, one that Qlik engendered, and Qlik Sense is designed to take advantage of. Think about how Qlik Sense Desktop was made available as a freemium offer. Information as an asset and differentiator As times change, so do differentiators. For example, car manufacturers in the 1980s differentiated themselves based on reliability, making sure their cars started every single time. Today, we expect that our cars will start; reliability is now a commodity. The same is true for ERP systems. Originally, companies implemented ERPs to improve reliability, but in today's post-ERP world, companies are shifting to differentiating their businesses based on information. This means our focus changes from apps to analytics. And analytics apps, like those delivered by Qlik Sense, help companies access the data they need to set themselves apart from the competition. However, to get maximum return from information, the analysis must be delivered fast enough, and in sync with the operational tempo people need. Things are speeding up all the time. For example, take the fashion industry. Large mainstream fashion retailers used to work two seasons per year. Those that stuck to that were destroyed by fast fashion retailers. The same is true for old style, system-of-record BI tools; they just can't cope with today's demands for speed and agility. The rise of information activism A new, tech-savvy generation is entering the workforce, and their expectations are different than those of past generations. The Beloit College Mindset List for the entering class of 2017 gives the perspective of students entering college this year, how they see the world, and the reality they've known all their lives. For this year's freshman class, Java has never been just a cup of coffee and a tablet is no longer something you take in the morning. This new generation of workers grew up with the Internet and is less likely to be passive with data. They bring their own devices everywhere they go, and expect it to be easy to mash-up data, communicate, and collaborate with their peers. The evolution and elevation of the role of IT We've all read about how the role of IT is changing, and the question CIOs today must ask themselves is: "How do we drive innovation?". IT must transform from being gatekeepers (doers) to storekeepers (enablers), providing business users with self-service tools they need to be successful. However, to achieve this transformation, they need to stock helpful tools and provide consumable information products or apps. Qlik Sense is a key part of the armory that IT needs to provide to be successful in this transformation. Summary In this article, we looked at the factors that provide the wider context for the use of Qlik Sense. The factors covered arise out of both increasing technical capability and demands to compete in a globalized, information-centric world, where out-analyzing your competitors is a key success factor. Resources for Article: Further resources on this subject: Securing QlikView Documents [article] Conozca QlikView [article] Introducing QlikView elements [article]

In article by Alberto Paro, the author of ElasticSearch Cookbook Second Edition, we will cover about the following recipes: (For more resources related to this topic, see here.) Installing additional script plugins Managing scripts Sorting data using scripts Computing return fields with scripting Filtering a search via scripting Introduction ElasticSearch has a powerful way of extending its capabilities with custom scripts, which can be written in several programming languages. The most common ones are Groovy, MVEL, JavaScript, and Python. In this article, we will see how it's possible to create custom scoring algorithms, special processed return fields, custom sorting, and complex update operations on records. The scripting concept of ElasticSearch can be seen as an advanced stored procedures system in the NoSQL world; so, for an advanced usage of ElasticSearch, it is very important to master it. Installing additional script plugins ElasticSearch provides native scripting (a Java code compiled in JAR) and Groovy, but a lot of interesting languages are also available, such as JavaScript and Python. In older ElasticSearch releases, prior to version 1.4, the official scripting language was MVEL, but due to the fact that it was not well-maintained by MVEL developers, in addition to the impossibility to sandbox it and prevent security issues, MVEL was replaced with Groovy. Groovy scripting is now provided by default in ElasticSearch. The other scripting languages can be installed as plugins. Getting ready You will need a working ElasticSearch cluster. How to do it... In order to install JavaScript language support for ElasticSearch (1.3.x), perform the following steps: From the command line, simply enter the following command: bin/plugin --install elasticsearch/elasticsearch-lang-javascript/2.3.0 This will print the following result: -> Installing elasticsearch/elasticsearch-lang-javascript/2.3.0... Trying http://download.elasticsearch.org/elasticsearch/elasticsearch-lang-javascript/ elasticsearch-lang-javascript-2.3.0.zip... Downloading ....DONE Installed lang-javascript If the installation is successful, the output will end with Installed; otherwise, an error is returned. To install Python language support for ElasticSearch, just enter the following command: bin/plugin -install elasticsearch/elasticsearch-lang-python/2.3.0 The version number depends on the ElasticSearch version. Take a look at the plugin's web page to choose the correct version. How it works... Language plugins allow you to extend the number of supported languages to be used in scripting. During the ElasticSearch startup, an internal ElasticSearch service called PluginService loads all the installed language plugins. In order to install or upgrade a plugin, you need to restart the node. The ElasticSearch community provides common scripting languages (a list of the supported scripting languages is available on the ElasticSearch site plugin page at http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-plugins.html), and others are available in GitHub repositories (a simple search on GitHub allows you to find them). The following are the most commonly used languages for scripting: Groovy (http://groovy.codehaus.org/): This language is embedded in ElasticSearch by default. It is a simple language that provides scripting functionalities. This is one of the fastest available language extensions. Groovy is a dynamic, object-oriented programming language with features similar to those of Python, Ruby, Perl, and Smalltalk. It also provides support to write a functional code. JavaScript (https://github.com/elasticsearch/elasticsearch-lang-javascript): This is available as an external plugin. The JavaScript implementation is based on Java Rhino (https://developer.mozilla.org/en-US/docs/Rhino) and is really fast. Python (https://github.com/elasticsearch/elasticsearch-lang-python): This is available as an external plugin, based on Jython (http://jython.org). It allows Python to be used as a script engine. Considering several benchmark results, it's slower than other languages. There's more... Groovy is preferred if the script is not too complex; otherwise, a native plugin provides a better environment to implement complex logic and data management. The performance of every language is different; the fastest one is the native Java. In the case of dynamic scripting languages, Groovy is faster, as compared to JavaScript and Python. In order to access document properties in Groovy scripts, the same approach will work as in other scripting languages: doc.score: This stores the document's score. doc['field_name'].value: This extracts the value of the field_name field from the document. If the value is an array or if you want to extract the value as an array, you can use doc['field_name'].values. doc['field_name'].empty: This returns true if the field_name field has no value in the document. doc['field_name'].multivalue: This returns true if the field_name field contains multiple values. If the field contains a geopoint value, additional methods are available, as follows: doc['field_name'].lat: This returns the latitude of a geopoint. If you need the value as an array, you can use the doc['field_name'].lats method. doc['field_name'].lon: This returns the longitude of a geopoint. If you need the value as an array, you can use the doc['field_name'].lons method. doc['field_name'].distance(lat,lon): This returns the plane distance, in miles, from a latitude/longitude point. If you need to calculate the distance in kilometers, you should use the doc['field_name'].distanceInKm(lat,lon) method. doc['field_name'].arcDistance(lat,lon): This returns the arc distance, in miles, from a latitude/longitude point. If you need to calculate the distance in kilometers, you should use the doc['field_name'].arcDistanceInKm(lat,lon) method. doc['field_name'].geohashDistance(geohash): This returns the distance, in miles, from a geohash value. If you need to calculate the same distance in kilometers, you should use doc['field_name'] and the geohashDistanceInKm(lat,lon) method. By using these helper methods, it is possible to create advanced scripts in order to boost a document by a distance that can be very handy in developing geolocalized centered applications. Managing scripts Depending on your scripting usage, there are several ways to customize ElasticSearch to use your script extensions. In this recipe, we will see how to provide scripts to ElasticSearch via files, indexes, or inline. Getting ready You will need a working ElasticSearch cluster populated with the populate script (chapter_06/populate_aggregations.sh), available at https://github.com/aparo/ elasticsearch-cookbook-second-edition. How to do it... To manage scripting, perform the following steps: Dynamic scripting is disabled by default for security reasons; we need to activate it in order to use dynamic scripting languages such as JavaScript or Python. To do this, we need to turn off the disable flag (script.disable_dynamic: false) in the ElasticSearch configuration file (config/elasticseach.yml) and restart the cluster. To increase security, ElasticSearch does not allow you to specify scripts for non-sandbox languages. Scripts can be placed in the scripts directory inside the configuration directory. To provide a script in a file, we'll put a my_script.groovy script in the config/scripts location with the following code content: doc["price"].value * factor If the dynamic script is enabled (as done in the first step), ElasticSearch allows you to store the scripts in a special index, .scripts. To put my_script in the index, execute the following command in the command terminal: curl -XPOST localhost:9200/_scripts/groovy/my_script -d '{ "script":"doc["price"].value * factor" }' The script can be used by simply referencing it in the script_id field; use the following command: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "match_all": {} }, "sort": {    "_script" : {      "script_id" : "my_script",      "lang" : "groovy",      "type" : "number",      "ignore_unmapped" : true,      "params" : {        "factor" : 1.1      },      "order" : "asc"    } } }' How it works... ElasticSearch allows you to load your script in different ways; each one of these methods has their pros and cons. The most secure way to load or import scripts is to provide them as files in the config/scripts directory. This directory is continuously scanned for new files (by default, every 60 seconds). The scripting language is automatically detected by the file extension, and the script name depends on the filename. If the file is put in subdirectories, the directory path becomes part of the filename; for example, if it is config/scripts/mysub1/mysub2/my_script.groovy, the script name will be mysub1_mysub2_my_script. If the script is provided via a filesystem, it can be referenced in the code via the "script": "script_name" parameter. Scripts can also be available in the special .script index. These are the REST end points: To retrieve a script, use the following code: GET http://<server>/_scripts/<language>/<id"> To store a script use the following code: PUT http://<server>/_scripts/<language>/<id> To delete a script use the following code: DELETE http://<server>/_scripts/<language>/<id> The indexed script can be referenced in the code via the "script_id": "id_of_the_script" parameter. The recipes that follow will use inline scripting because it's easier to use it during the development and testing phases. Generally, a good practice is to develop using the inline dynamic scripting in a request, because it's faster to prototype. Once the script is ready and no changes are needed, it can be stored in the index since it is simpler to call and manage. In production, a best practice is to disable dynamic scripting and store the script on the disk (generally, dumping the indexed script to disk). See also The scripting page on the ElasticSearch website at http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-scripting.html Sorting data using script ElasticSearch provides scripting support for the sorting functionality. In real world applications, there is often a need to modify the default sort by the match score using an algorithm that depends on the context and some external variables. Some common scenarios are given as follows: Sorting places near a point Sorting by most-read articles Sorting items by custom user logic Sorting items by revenue Getting ready You will need a working ElasticSearch cluster and an index populated with the script, which is available at https://github.com/aparo/ elasticsearch-cookbook-second-edition. How to do it... In order to sort using scripting, perform the following steps: If you want to order your documents by the price field multiplied by a factor parameter (that is, sales tax), the search will be as shown in the following code: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "match_all": {} }, "sort": {    "_script" : {      "script" : "doc["price"].value * factor",      "lang" : "groovy",      "type" : "number",      "ignore_unmapped" : true,    "params" : {        "factor" : 1.1      },            "order" : "asc"        }    } }' In this case, we have used a match_all query and a sort script. If everything is correct, the result returned by ElasticSearch should be as shown in the following code: { "took" : 7, "timed_out" : false, "_shards" : {    "total" : 5,    "successful" : 5,    "failed" : 0 }, "hits" : {    "total" : 1000,    "max_score" : null,    "hits" : [ {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "161",      "_score" : null, "_source" : … truncated …,      "sort" : [ 0.0278578661440021 ]    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "634",      "_score" : null, "_source" : … truncated …,     "sort" : [ 0.08131364254827411 ]    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "465",      "_score" : null, "_source" : … truncated …,      "sort" : [ 0.1094966959069832 ]    } ] } } How it works... The sort scripting allows you to define several parameters, as follows: order (default "asc") ("asc" or "desc"): This determines whether the order must be ascending or descending. script: This contains the code to be executed. type: This defines the type to convert the value. params (optional, a JSON object): This defines the parameters that need to be passed. lang (by default, groovy): This defines the scripting language to be used. ignore_unmapped (optional): This ignores unmapped fields in a sort. This flag allows you to avoid errors due to missing fields in shards. Extending the sort with scripting allows the use of a broader approach to score your hits. ElasticSearch scripting permits the use of every code that you want. You can create custom complex algorithms to score your documents. There's more... Groovy provides a lot of built-in functions (mainly taken from Java's Math class) that can be used in scripts, as shown in the following table: Function Description time() The current time in milliseconds sin(a) Returns the trigonometric sine of an angle cos(a) Returns the trigonometric cosine of an angle tan(a) Returns the trigonometric tangent of an angle asin(a) Returns the arc sine of a value acos(a) Returns the arc cosine of a value atan(a) Returns the arc tangent of a value toRadians(angdeg) Converts an angle measured in degrees to an approximately equivalent angle measured in radians toDegrees(angrad) Converts an angle measured in radians to an approximately equivalent angle measured in degrees exp(a) Returns Euler's number raised to the power of a value log(a) Returns the natural logarithm (base e) of a value log10(a) Returns the base 10 logarithm of a value sqrt(a) Returns the correctly rounded positive square root of a value cbrt(a) Returns the cube root of a double value IEEEremainder(f1, f2) Computes the remainder operation on two arguments, as prescribed by the IEEE 754 standard ceil(a) Returns the smallest (closest to negative infinity) value that is greater than or equal to the argument and is equal to a mathematical integer floor(a) Returns the largest (closest to positive infinity) value that is less than or equal to the argument and is equal to a mathematical integer rint(a) Returns the value that is closest in value to the argument and is equal to a mathematical integer atan2(y, x) Returns the angle theta from the conversion of rectangular coordinates (x,y_) to polar coordinates (r,_theta) pow(a, b) Returns the value of the first argument raised to the power of the second argument round(a) Returns the closest integer to the argument random() Returns a random double value abs(a) Returns the absolute value of a value max(a, b) Returns the greater of the two values min(a, b) Returns the smaller of the two values ulp(d) Returns the size of the unit in the last place of the argument signum(d) Returns the signum function of the argument sinh(x) Returns the hyperbolic sine of a value cosh(x) Returns the hyperbolic cosine of a value tanh(x) Returns the hyperbolic tangent of a value hypot(x,y) Returns sqrt(x^2+y^2) without an intermediate overflow or underflow acos(a) Returns the arc cosine of a value atan(a) Returns the arc tangent of a value If you want to retrieve records in a random order, you can use a script with a random method, as shown in the following code: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "match_all": {} }, "sort": {    "_script" : {      "script" : "Math.random()",      "lang" : "groovy",      "type" : "number",      "params" : {}    } } }' In this example, for every hit, the new sort value is computed by executing the Math.random() scripting function. See also The official ElasticSearch documentation at http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-scripting.html Computing return fields with scripting ElasticSearch allows you to define complex expressions that can be used to return a new calculated field value. These special fields are called script_fields, and they can be expressed with a script in every available ElasticSearch scripting language. Getting ready You will need a working ElasticSearch cluster and an index populated with the script (chapter_06/populate_aggregations.sh), which is available at https://github.com/aparo/ elasticsearch-cookbook-second-edition. How to do it... In order to compute return fields with scripting, perform the following steps: Return the following script fields: "my_calc_field": This concatenates the text of the "name" and "description" fields "my_calc_field2": This multiplies the "price" value by the "discount" parameter From the command line, execute the following code: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/ _search?&pretty=true&size=3' -d '{ "query": {    "match_all": {} }, "script_fields" : {    "my_calc_field" : {      "script" : "doc["name"].value + " -- " + doc["description"].value"    },    "my_calc_field2" : {      "script" : "doc["price"].value * discount",      "params" : {       "discount" : 0.8      }    } } }' If everything works all right, this is how the result returned by ElasticSearch should be: { "took" : 4, "timed_out" : false, "_shards" : {    "total" : 5,    "successful" : 5,    "failed" : 0 }, "hits" : {    "total" : 1000,    "max_score" : 1.0,    "hits" : [ {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "4",      "_score" : 1.0,      "fields" : {        "my_calc_field" : "entropic -- accusantium",        "my_calc_field2" : 5.480038242170081      }    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "9",      "_score" : 1.0,      "fields" : {        "my_calc_field" : "frankie -- accusantium",        "my_calc_field2" : 34.79852410178313      }    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "11",      "_score" : 1.0,      "fields" : {        "my_calc_field" : "johansson -- accusamus",        "my_calc_field2" : 11.824173084636591      }    } ] } } How it works... The scripting fields are similar to executing an SQL function on a field during a select operation. In ElasticSearch, after a search phase is executed and the hits to be returned are calculated, if some fields (standard or script) are defined, they are calculated and returned. The script field, which can be defined with all the supported languages, is processed by passing a value to the source of the document and, if some other parameters are defined in the script (in the discount factor example), they are passed to the script function. The script function is a code snippet; it can contain everything that the language allows you to write, but it must be evaluated to a value (or a list of values). See also The Installing additional script plugins recipe in this article to install additional languages for scripting The Sorting using script recipe to have a reference of the extra built-in functions in Groovy scripts Filtering a search via scripting ElasticSearch scripting allows you to extend the traditional filter with custom scripts. Using scripting to create a custom filter is a convenient way to write scripting rules that are not provided by Lucene or ElasticSearch, and to implement business logic that is not available in the query DSL. Getting ready You will need a working ElasticSearch cluster and an index populated with the (chapter_06/populate_aggregations.sh) script, which is available at https://github.com/aparo/ elasticsearch-cookbook-second-edition. How to do it... In order to filter a search using a script, perform the following steps: Write a search with a filter that filters out a document with the value of age less than the parameter value: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "filtered": {      "filter": {        "script": {          "script": "doc["age"].value > param1",          "params" : {            "param1" : 80          }        }      },      "query": {        "match_all": {}      }    } } }' In this example, all the documents in which the value of age is greater than param1 are qualified to be returned. If everything works correctly, the result returned by ElasticSearch should be as shown here: { "took" : 30, "timed_out" : false, "_shards" : {    "total" : 5,    "successful" : 5,    "failed" : 0 }, "hits" : {    "total" : 237,    "max_score" : 1.0,    "hits" : [ {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "9",      "_score" : 1.0, "_source" :{ … "age": 83, … }    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "23",      "_score" : 1.0, "_source" : { … "age": 87, … }    }, {      "_index" : "test-index",      "_type" : "test-type",      "_id" : "47",      "_score" : 1.0, "_source" : {…. "age": 98, …}    } ] } } How it works... The script filter is a language script that returns a Boolean value (true/false). For every hit, the script is evaluated, and if it returns true, the hit passes the filter. This type of scripting can only be used as Lucene filters, not as queries, because it doesn't affect the search (the exceptions are constant_score and custom_filters_score). These are the scripting fields: script: This contains the code to be executed params: These are optional parameters to be passed to the script lang (defaults to groovy): This defines the language of the script The script code can be any code in your preferred and supported scripting language that returns a Boolean value. There's more... Other languages are used in the same way as Groovy. For the current example, I have chosen a standard comparison that works in several languages. To execute the same script using the JavaScript language, use the following code: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "filtered": {      "filter": {        "script": {          "script": "doc["age"].value > param1",          "lang":"javascript",          "params" : {            "param1" : 80          }        }      },      "query": {        "match_all": {}      }    } } }' For Python, use the following code: curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?&pretty=true&size=3' -d '{ "query": {    "filtered": {      "filter": {        "script": {          "script": "doc["age"].value > param1",          "lang":"python",          "params" : {            "param1" : 80          }        }      },      "query": {        "match_all": {}      }    } } }' See also The Installing additional script plugins recipe in this article to install additional languages for scripting The Sorting data using script recipe in this article to get a reference of the extra built-in functions in Groovy scripts Summary In this article you have learnt the ways you can use scripting to extend the ElasticSearch functional capabilities using different programming languages. Resources for Article: Further resources on this subject: Indexing the Data [Article] Low-Level Index Control [Article] Designing Puppet Architectures [Article]