How-To Tutorials

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 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]

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, 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 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]

In this article, by Aloysius Lim and William Tjhi, authors of the book R High Performance Programming, we will learn how to write and execute a parallel R code, where different parts of the code run simultaneously. So far, we have learned various ways to optimize the performance of R programs running serially, that is in a single process. This does not take full advantage of the computing power of modern CPUs with multiple cores. Parallel computing allows us to tap into all the computational resources available and to speed up the execution of R programs by many times. We will examine the different types of parallelism and how to implement them in R, and we will take a closer look at a few performance considerations when designing the parallel architecture of R programs. (For more resources related to this topic, see here.) Data parallelism versus task parallelism Many modern software applications are designed to run computations in parallel in order to take advantage of the multiple CPU cores available on almost any computer today. Many R programs can similarly be written in order to run in parallel. However, the extent of possible parallelism depends on the computing task involved. On one side of the scale are embarrassingly parallel tasks, where there are no dependencies between the parallel subtasks; such tasks can be made to run in parallel very easily. An example of this is, building an ensemble of decision trees in a random forest algorithm—randomized decision trees can be built independently from one another and in parallel across tens or hundreds of CPUs, and can be combined to form the random forest. On the other end of the scale are tasks that cannot be parallelized, as each step of the task depends on the results of the previous step. One such example is a depth-first search of a tree, where the subtree to search at each step depends on the path taken in previous steps. Most algorithms fall somewhere in between with some steps that must run serially and some that can run in parallel. With this in mind, careful thought must be given when designing a parallel code that works correctly and efficiently. Often an R program has some parts that have to be run serially and other parts that can run in parallel. Before making the effort to parallelize any of the R code, it is useful to have an estimate of the potential performance gains that can be achieved. Amdahl's law provides a way to estimate the best attainable performance gain when you convert a code from serial to parallel execution. It divides a computing task into its serial and potentially-parallel parts and states that the time needed to execute the task in parallel will be no less than this formula: T(n) = T(1)(P + (1-P)/n), where: T(n) is the time taken to execute the task using n parallel processes P is the proportion of the whole task that is strictly serial The theoretical best possible speed up of the parallel algorithm is thus: S(n) = T(1) / T(n) = 1 / (P + (1-P)/n) For example, given a task that takes 10 seconds to execute on one processor, where half of the task can be run in parallel, then the best possible time to run it on four processors is T(4) = 10(0.5 + (1-0.5)/4) = 6.25 seconds. The theoretical best possible speed up of the parallel algorithm with four processors is 1 / (0.5 + (1-0.5)/4) = 1.6x . The following figure shows you how the theoretical best possible execution time decreases as more CPU cores are added. Notice that the execution time reaches a limit that is just above five seconds. This corresponds to the half of the task that must be run serially, where parallelism does not help. Best possible execution time versus number of CPU cores In general, Amdahl's law means that the fastest execution time for any parallelized algorithm is limited by the time needed for the serial portions of the algorithm. Bear in mind that Amdahl's law provides only a theoretical estimate. It does not account for the overheads of parallel computing (such as starting and coordinating tasks) and assumes that the parallel portions of the algorithm are infinitely scalable. In practice, these factors might significantly limit the performance gains of parallelism, so use Amdahl's law only to get a rough estimate of the maximum speedup possible. There are two main classes of parallelism: data parallelism and task parallelism. Understanding these concepts helps to determine what types of tasks can be modified to run in parallel. In data parallelism, a dataset is divided into multiple partitions. Different partitions are distributed to multiple processors, and the same task is executed on each partition of data. Take for example, the task of finding the maximum value in a vector dataset, say one that has one billion numeric data points. A serial algorithm to do this would look like the following code, which iterates over every element of the data in sequence to search for the largest value. (This code is intentionally verbose to illustrate how the algorithm works; in practice, the max() function in R, though also serial in nature, is much faster.) serialmax <- function(data) {max = -Inffor (i in data) {if (i > max)max = i}return max} One way to parallelize this algorithm is to split the data into partitions. If we have a computer with eight CPU cores, we can split the data into eight partitions of 125 million numbers each. Here is the pseudocode for how to perform the same task in parallel: # Run this in parallel across 8 CPU corespart.results <- run.in.parallel(serialmax(data.part))# Compute global maxglobal.max <- serialmax(part.results) This pseudocode runs eight instances of serialmax()in parallel—one for each data partition—to find the local maximum value in each partition. Once all the partitions have been processed, the algorithm finds the global maximum value by finding the largest value among the local maxima. This parallel algorithm works because the global maximum of a dataset must be the largest of the local maxima from all the partitions. The following figure depicts data parallelism pictorially. The key behind data parallel algorithms is that each partition of data can be processed independently of the other partitions, and the results from all the partitions can be combined to compute the final results. This is similar to the mechanism of the MapReduce framework from Hadoop. Data parallelism allows algorithms to scale up easily as data volume increases—as more data is added to the dataset, more computing nodes can be added to a cluster to process new partitions of data. Data parallelism Other examples of computations and algorithms that can be run in a data parallel way include: Element-wise matrix operations such as addition and subtraction: The matrices can be partitioned and the operations are applied to each pair of partitions. Means: The sums and number of elements in each partition can be added to find the global sum and number of elements from which the mean can be computed. K-means clustering: After data partitioning, the K centroids are distributed to all the partitions. Finding the closest centroid is performed in parallel and independently across the partitions. The centroids are updated by first, calculating the sums and the counts of their respective members in parallel, and then consolidating them in a single process to get the global means. Frequent itemset mining using the Partition algorithm: In the first pass, the frequent itemsets are mined from each partition of data to generate a global set of candidate itemsets; in the second pass, the supports of the candidate itemsets are summed from each partition to filter out the globally infrequent ones. The other main class of parallelism is task parallelism, where tasks are distributed to and executed on different processors in parallel. The tasks on each processor might be the same or different, and the data that they act on might also be the same or different. The key difference between task parallelism and data parallelism is that the data is not divided into partitions. An example of a task parallel algorithm performing the same task on the same data is the training of a random forest model. A random forest is a collection of decision trees built independently on the same data. During the training process for a particular tree, a random subset of the data is chosen as the training set, and the variables to consider at each branch of the tree are also selected randomly. Hence, even though the same data is used, the trees are different from one another. In order to train a random forest of say 100 decision trees, the workload could be distributed to a computing cluster with 100 processors, with each processor building one tree. All the processors perform the same task on the same data (or exact copies of the data), but the data is not partitioned. The parallel tasks can also be different. For example, computing a set of summary statistics on the same set of data can be done in a task parallel way. Each process can be assigned to compute a different statistic—the mean, standard deviation, percentiles, and so on. Pseudocode of a task parallel algorithm might look like this: # Run 4 tasks in parallel across 4 coresfor (task in tasks)run.in.parallel(task)# Collect the results of the 4 tasksresults <- collect.parallel.output()# Continue processing after all 4 tasks are complete Implementing data parallel algorithms Several R packages allow code to be executed in parallel. The parallel package that comes with R provides the foundation for most parallel computing capabilities in other packages. Let's see how it works with an example. This example involves finding documents that match a regular expression. Regular expression matching is a fairly computational expensive task, depending on the complexity of the regular expression. The corpus, or set of documents, for this example is a sample of the Reuters-21578 dataset for the topic corporate acquisitions (acq) from the tm package. Because this dataset contains only 50 documents, they are replicated 100,000 times to form a corpus of 5 million documents so that parallelizing the code will lead to meaningful savings in execution times. library(tm)data("acq")textdata <- rep(sapply(content(acq), content), 1e5) The task is to find documents that match the regular expression d+(,d+)? mln dlrs, which represents monetary amounts in millions of dollars. In this regular expression, d+ matches a string of one or more digits, and (,d+)? optionally matches a comma followed by one more digits. For example, the strings 12 mln dlrs, 1,234 mln dlrs and 123,456,789 mln dlrs will match the regular expression. First, we will measure the execution time to find these documents serially with grepl(): pattern <- "\d+(,\d+)? mln dlrs"system.time(res1 <- grepl(pattern, textdata))##   user  system elapsed ## 65.601   0.114  65.721 Next, we will modify the code to run in parallel and measure the execution time on a computer with four CPU cores: library(parallel)detectCores()## [1] 4cl <- makeCluster(detectCores())part <- clusterSplit(cl, seq_along(textdata))text.partitioned <- lapply(part, function(p) textdata[p])system.time(res2 <- unlist(    parSapply(cl, text.partitioned, grepl, pattern = pattern))) ##  user  system elapsed ## 3.708   8.007  50.806 stopCluster(cl) In this code, the detectCores() function reveals how many CPU cores are available on the machine, where this code is executed. Before running any parallel code, makeCluster() is called to create a local cluster of processing nodes with all four CPU cores. The corpus is then split into four partitions using the clusterSplit() function to determine the ideal split of the corpus such that each partition has roughly the same number of documents. The actual parallel execution of grepl() on each partition of the corpus is carried out by the parSapply() function. Each processing node in the cluster is given a copy of the partition of data that it is supposed to process along with the code to be executed and other variables that are needed to run the code (in this case, the pattern argument). When all four processing nodes have completed their tasks, the results are combined in a similar fashion to sapply(). Finally, the cluster is destroyed by calling stopCluster(). It is good practice to ensure that stopCluster() is always called in production code, even if an error occurs during execution. This can be done as follows: doSomethingInParallel <- function(...) {    cl <- makeCluster(...)    on.exit(stopCluster(cl))    # do something} In this example, running the task in parallel on four processors resulted in a 23 percent reduction in the execution time. This is not in proportion to the amount of compute resources used to perform the task; with four times as many CPU cores working on it, a perfectly parallelizable task might experience as much as a 75 percent runtime reduction. However, remember Amdahl's law—the speed of parallel code is limited by the serial parts, which includes the overheads of parallelization. In this case, calling makeCluster() with the default arguments creates a socket-based cluster. When such a cluster is created, additional copies of R are run as workers. The workers communicate with the master R process using network sockets, hence the name. The worker R processes are initialized with the relevant packages loaded, and data partitions are serialized and sent to each worker process. These overheads can be significant, especially in data parallel algorithms where large volumes of data needs to be transferred to the worker processes. Besides parSapply(), parallel also provides the parApply() and parLapply() functions; these functions are analogous to the standard sapply(), apply(), and lapply() functions, respectively. In addition, the parLapplyLB() and parSapplyLB() functions provide load balancing, which is useful when the execution of each parallel task takes variable amounts of time. Finally, parRapply() and parCapply() are parallel row and column apply() functions for matrices. On non-Windows systems, parallel supports another type of cluster that often incurs less overheads — forked clusters. In these clusters, new worker processes are forked from the parent R process with a copy of the data. However, the data is not actually copied in the memory unless it is modified by a child process. This means that, compared to socket-based clusters, initializing child processes is quicker and the memory usage is often lower. Another advantage of using forked clusters is that parallel provides a convenient and concise way to run tasks on them via the mclapply(), mcmapply(), and mcMap() functions. (These functions start with mc because they were originally a part of the multicore package) There is no need to explicitly create and destroy the cluster, as these functions do this automatically. We can simply call mclapply() and state the number of worker processes to fork via the mc.cores argument: system.time(res3 <- unlist(    mclapply(text.partitioned, grepl, pattern = pattern,             mc.cores = detectCores())))##    user  system elapsed ## 127.012   0.350  33.264 This shows a 49 percent reduction in execution time compared to the serial version, and 35 percent reduction compared to parallelizing using a socket-based cluster. For this example, forked clusters provide the best performance. Due to differences in system configuration, you might see very different results when you try the examples in your own environment. When you develop parallel code, it is important to test the code in an environment that is similar to the one that it will eventually run in. Implementing task parallel algorithms Let's now see how to implement a task parallel algorithm using both socket-based and forked clusters. We will look at how to run the same task and different tasks on workers in a cluster. Running the same task on workers in a cluster To demonstrate how to run the same task on a cluster, the task for this example is to generate 500 million Poisson random numbers. We will do this by using L'Ecuyer's combined multiple-recursive generator, which is the only random number generator in base R that supports multiple streams to generate random numbers in parallel. The random number generator is selected by calling the RNGkind() function. We cannot just use any random number generator in parallel because the randomness of the data depends on the algorithm used to generate random data and the seed value given to each parallel task. Most other algorithms were not designed to produce random numbers in multiple parallel streams, and might produce multiple highly correlated streams of numbers, or worse, multiple identical streams! First, we will measure the execution time of the serial algorithm: RNGkind("L'Ecuyer-CMRG")nsamples <- 5e8lambda <- 10system.time(random1 <- rpois(nsamples, lambda))##   user  system elapsed## 51.905   0.636  52.544 To generate the random numbers on a cluster, we will first distribute the task evenly among the workers. In the following code, the integer vector samples.per.process contains the number of random numbers that each worker needs to generate on a four-core CPU. The seq() function produces ncores+1 numbers evenly distributed between 0 and nsamples, with the first number being 0 and the next ncores numbers indicating the approximate cumulative number of samples across the worker processes. The round() function rounds off these numbers into integers and diff() computes the difference between them to give the number of random numbers that each worker process should generate. cores <- detectCores()cl <- makeCluster(ncores)samples.per.process <-    diff(round(seq(0, nsamples, length.out = ncores+1))) Before we can generate the random numbers on a cluster, each worker needs a different seed from which it can generate a stream of random numbers. The seeds need to be set on all the workers before running the task, to ensure that all the workers generate different random numbers. For a socket-based cluster, we can call clusterSetRNGStream() to set the seeds for the workers, then run the random number generation task on the cluster. When the task is completed, we call stopCluster() to shut down the cluster: clusterSetRNGStream(cl)system.time(random2 <- unlist(    parLapply(cl, samples.per.process, rpois,               lambda = lambda)))##  user  system elapsed ## 5.006   3.000  27.436stopCluster(cl) Using four parallel processes in a socket-based cluster reduces the execution time by 48 percent. The performance of this type of cluster for this example is better than that of the data parallel example because there is less data to copy to the worker processes—only an integer that indicates how many random numbers to generate. Next, we run the same task on a forked cluster (again, this is not supported on Windows). The mclapply() function can set the random number seeds for each worker for us, when the mc.set.seed argument is set to TRUE; we do not need to call clusterSetRNGStream(). Otherwise, the code is similar to that of the socket-based cluster: system.time(random3 <- unlist(    mclapply(samples.per.process, rpois,             lambda = lambda,             mc.set.seed = TRUE, mc.cores = ncores))) ##   user  system elapsed ## 76.283   7.272  25.052 On our test machine, the execution time of the forked cluster is slightly faster, but close to that of the socket-based cluster, indicating that the overheads for this task are similar for both types of clusters. Running different tasks on workers in a cluster So far, we have executed the same tasks on each parallel process. The parallel package also allows different tasks to be executed on different workers. For this example, the task is to generate not only Poisson random numbers, but also uniform, normal, and exponential random numbers. As before, we start by measuring the time to perform this task serially: RNGkind("L'Ecuyer-CMRG")nsamples <- 5e7pois.lambda <- 10system.time(random1 <- list(pois = rpois(nsamples,                                          pois.lambda),                            unif = runif(nsamples),                            norm = rnorm(nsamples),                            exp = rexp(nsamples)))##   user  system elapsed ## 14.180   0.384  14.570 In order to run different tasks on different workers on socket-based clusters, a list of function calls and their associated arguments must be passed to parLapply(). This is a bit cumbersome, but parallel unfortunately does not provide an easier interface to run different tasks on a socket-based cluster. In the following code, the function calls are represented as a list of lists, where the first element of each sublist is the name of the function that runs on a worker, and the second element contains the function arguments. The function do.call() is used to call the given function with the given arguments. cores <- detectCores()cl <- makeCluster(cores)calls <- list(pois = list("rpois", list(n = nsamples,                                        lambda = pois.lambda)),              unif = list("runif", list(n = nsamples)),              norm = list("rnorm", list(n = nsamples)),              exp = list("rexp", list(n = nsamples)))clusterSetRNGStream(cl)system.time(    random2 <- parLapply(cl, calls,                         function(call) {                             do.call(call[[1]], call[[2]])                         }))##  user  system elapsed ## 2.185   1.629  10.403stopCluster(cl) On forked clusters on non-Windows machines, the mcparallel() and mccollect() functions offer a more intuitive way to run different tasks on different workers. For each task, mcparallel() sends the given task to an available worker. Once all the workers have been assigned their tasks, mccollect() waits for the workers to complete their tasks and collects the results from all the workers. mc.reset.stream()system.time({    jobs <- list()    jobs[[1]] <- mcparallel(rpois(nsamples, pois.lambda),                            "pois", mc.set.seed = TRUE)    jobs[[2]] <- mcparallel(runif(nsamples),                            "unif", mc.set.seed = TRUE)    jobs[[3]] <- mcparallel(rnorm(nsamples),                            "norm", mc.set.seed = TRUE)    jobs[[4]] <- mcparallel(rexp(nsamples),                            "exp", mc.set.seed = TRUE)    random3 <- mccollect(jobs)})##   user  system elapsed ## 14.535   3.569   7.97 Notice that we also had to call mc.reset.stream() to set the seeds for random number generation in each worker. This was not necessary when we used mclapply(), which calls mc.reset.stream() for us. However, mcparallel() does not, so we need to call it ourselves. Summary In this article, we learned about two classes of parallelism: data parallelism and task parallelism. Data parallelism is good for tasks that can be performed in parallel on partitions of a dataset. The dataset to be processed is split into partitions and each partition is processed on a different worker processes. Task parallelism, on the other hand, divides a set of similar or different tasks to amongst the worker processes. In either case, Amdahl's law states that the maximum improvement in speed that can be achieved by parallelizing code is limited by the proportion of that code that can be parallelized. Resources for Article: Further resources on this subject: Using R for Statistics, Research, and Graphics [Article] Learning Data Analytics with R and Hadoop [Article] Aspects of Data Manipulation in R [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]

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 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]

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 the authors, Fabrizio Volpe, Alessio Giombini, Lasse Nordvik Wedø, and António Vargas of the book, Lync Server Cookbook, we will cover the following recipes: Introducing Lync Online Administering with the Lync Admin Center Using Lync Online Remote PowerShell Using Lync Online cmdlets Introducing Lync in a hybrid scenario Planning and configuring a hybrid deployment Moving users to the cloud Moving users back on-premises Debugging Lync Online issues (For more resources related to this topic, see here.) Introducing Lync Online Lync Online is part of the Office 365 offer and provides online users with the same Instant Messaging (IM), presence, and conferencing features that we would expect from an on-premises deployment of Lync Server 2013. Enterprise Voice, however, is not available on Office 365 tenants (or at least, it is available only with limitations regarding both specific Office 365 plans and geographical locations). There is no doubt that forthcoming versions of Lync and Office 365 will add what is needed to also support all the Enterprise Voice features in the cloud. Right now, the best that we are able to achieve is to move workloads, homing a part of our Lync users (the ones with no telephony requirements) in Office 365, while the remaining Lync users are homed on-premises. These solutions might be interesting for several reasons, including the fact that we can avoid the costs of expanding our existing on-premises resources by moving a part of our Lync-enabled users to Office 365. The previously mentioned configuration, which involves different kinds of Lync tenants, is called a hybrid deployment of Lync, and we will see how to configure it and move our users from online to on-premises and vice versa. In this Article, every time we talk about Lync Online and Office 365, we will assume that we have already configured an Office tenant. Administering with the Lync Admin Center Lync Online provides the Lync Admin Center (LAC), a dedicated control panel, to manage Lync settings. To open it, access the Office 365 portal and select Service settings, Lync, and Manage settings in the Lync admin center, as shown in the following screenshot: LAC, if you compare it with the on-premises Lync Control Panel (or with the Lync Management Shell), offers few options. For example, it is not possible to create or delete users directly inside Lync. We will see some of the tasks we are able to perform in LAC, and then, we will move to the (more powerful) Remote PowerShell. There is an alternative path to open LAC. From the Office 365 portal, navigate to Users & Groups | Active Users. Select a user, after which you will see a Quick Steps area with an Edit Lync Properties link that will open the user-editable part of LAC. How to do it... LAC is divided into five areas: users, organization, dial-in conferencing, meeting invitation, and tools, as you can see in the following screenshot: The Users panel will show us the configuration of the Lync Online enabled users. It is possible to modify the settings with the Edit option (the small pencil icon on the right): I have tried to summarize all the available options (inside the general, external communications, and dial-in conferencing tabs) in the following screenshot: Some of the user's settings are worth a mention; in the General tab, we have the following:    The Record Conversations and meetings option enables the Start recording option in the Lync client    The Allow anonymous attendees to dial-out option controls whether the anonymous users that are dialing-in to a conference are required to call the conferencing service directly or are authorized for callback    The For compliance, turn off non-archived features option disables Lync features that are not recorded by In-Place Hold for Exchange When you place an Exchange 2013 mailbox on In-Place Hold or Litigation Hold, the Microsoft Lync 2013 content (instant messaging conversations and files shared in an online meeting) is archived in the mailbox. In the dial-in conferencing tab, we have the configuration required for dial-in conferencing. The provider's drop-down menu shows a list of third parties that are able to deliver this kind of feature. The Organization tab manages privacy for presence information, push services, and external access (the equivalent of the Lync federation on-premises). If you enable external access, we will have the option to turn on Skype federation, as we can see in the following screenshot: The Dial-In Conferencing option is dedicated to the configuration of the external providers. The Meeting Invitation option allows the user to customize the Lync Meeting invitation. The Tools options offer a collection of troubleshooting resources. See also For details about Exchange In-Place Hold, see the TechNet post In-Place Hold and Litigation Hold at http://technet.microsoft.com/en-us/library/ff637980(v=exchg.150).aspx. Using Lync Online Remote PowerShell The possibility to manage Lync using Remote PowerShell on a distant deployment has been available since Lync 2010. This feature has always required a direct connection from the management station to the Remote Lync, and a series of steps that is not always simple to set up. Lync Online supports Remote PowerShell using a dedicated (64-bit only) PowerShell module, the Lync Online Connector. It is used to manage online users, and it is interesting because there are many settings and automation options that are available only through PowerShell. Getting ready Lync Online Connector requires one of the following operating systems: Windows 7 (with Service Pack 1), Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows 8, or Windows 8.1. At least PowerShell 3.0 is needed. To check it, we can use the $PSVersionTable variable. The result will be like the one in the following screenshot (taken on Windows 8.1, which uses PowerShell 4.0): How to do it... Download Windows PowerShell Module for Lync Online from the Microsoft site at http://www.microsoft.com/en-us/download/details.aspx?id=39366 and install it. It is useful to store our Office 365 credentials in an object (it is possible to launch the cmdlets at step 3 anyway, and we will be required with the Office 365 administrator credentials, but using this method, we will have to insert the authentication information again every time it is required). We can use the $credential = Get-Credential cmdlet in a PowerShell session. We will be prompted for our username and password for Lync Online, as shown in the following screenshot: To use the Online Connector, open a PowerShell session and use the New-CsOnlineSession cmdlet. One of the ways to start a remote PowerShell session is $session = New-CsOnlineSession -Credential $credential. Now, we need to import the session that we have created with Lync Online inside PowerShell, with the Import-PSSession $session cmdlet. A temporary Windows PowerShell module will be created, which contains all the Lync Online cmdlets. The name of the temporary module will be similar to the one we can see in the following screenshot: Now, we will have the cmdlets of the Lync Online module loaded in memory, in addition to any command that we already have available in PowerShell. How it works... The feature is based on a PowerShell module, the LyncOnlineConnector, shown in the following screenshot: It contains only two cmdlets, the Set-WinRMNetworkDelayMS and New-CsOnlineSession cmdlets. The latter will load the required cmdlets in memory. As we have seen in the previous steps, the Online Connector adds the Lync Online PowerShell cmdlets to the ones already available. This is something we will use when talking about hybrid deployments, where we will start from the Lync Management Shell and then import the module for Lync Online. It is a good habit to verify (and close) your previous remote sessions. This can be done by selecting a specific session (using Get-PSSession and then pointing to a specific session with the Remove-PSSession statement) or closing all the existing ones with the Get-PSSession | Remove-PSSession cmdlet. In the previous versions of the module, Microsoft Online Services Sign-In Assistant was required. This prerequisite was removed from the latest version. There's more... There are some checks that we are able to perform when using the PowerShell module for Lync Online. By launching the New-CsOnlineSession cmdlet with the –verbose switch, we will see all the messages related to the opening of the session. The result should be similar to the one shown in the following screenshot: Another verification comes from the Get-Command -Module tmp_gffrkflr.ufz command, where the module name (in this example, tmp_gffrkflr.ufz) is the temporary module we saw during the Import-PSSession step. The output of the command will show all the Lync Online cmdlets that we have loaded in memory. The Import-PSSession cmdlet imports all commands except the ones that have the same name of a cmdlet that already exists in the current PowerShell session. To overwrite the existing cmdlets, we can use the -AllowClobber parameter. See also During the introduction of this section, we also discussed the possibility to administer on-premises, remote Lync Server 2013 deployment with a remote PowerShell session. John Weber has written a great post about it in his blog Lync 2013 Remote Admin with PowerShell at http://tsoorad.blogspot.it/2013/10/lync-2013-remote-admin-with-powershell.html, which is helpful if you want to use the previously mentioned feature. Using Lync Online cmdlets In the previous recipe, we outlined the steps required to establish a remote PowerShell session with Lync Online. We have less than 50 cmdlets, as shown in the result of the Get-Command -Module command in the following screenshot: Some of them are specific for Lync Online, such as the following: Get-CsAudioConferencingProvider Get-CsOnlineUser Get-CsTenant Get-CsTenantFederationConfiguration Get-CsTenantHybridConfiguration Get-CsTenantLicensingConfiguration Get-CsTenantPublicProvider New-CsEdgeAllowAllKnownDomains New-CsEdgeAllowList New-CsEdgeDomainPattern Set-CsTenantFederationConfiguration Set-CsTenantHybridConfiguration Set-CsTenantPublicProvider Update-CsTenantMeetingUrl All the remaining cmdlets can be used either with Lync Online or with the on-premises version of Lync Server 2013. We will see the use of some of the previously mentioned cmdlets. How to do it... The Get-CsTenant cmdlet will list Lync Online tenants configured for use in our organization. The output of the command includes information such as the preferred language, registrar pool, domains, and assigned plan. The Get-CsTenantHybridConfiguration cmdlet gathers information about the hybrid configuration of Lync. Management of the federation capability for Lync Online (the feature that enables Instant Messaging and Presence information exchange with users of other domains) is based on the allowed domain and blocked domain lists, as we can see in the organization and external communications screen of LAC, shown in the following screenshot: There are similar ways to manage federation from the Lync Online PowerShell, but it required to put together different statements as follows:     We can use an accept all domains excluding the ones in the exceptions list approach. To do this, we have put the New-CsEdgeAllowAllKnownDomains cmdlet inside a variable. Then, we can use the Set-CsTenantFederationConfiguration cmdlet to allow all the domains (except the ones in the block list) for one of our domains on a tenant. We can use the example on TechNet (http://technet.microsoft.com/en-us/library/jj994088.aspx) and integrate it with Get-CsTenant.     If we prefer, we can use a block all domains but permit the ones in the allow list approach. It is required to define a domain name (pattern) for every domain to allow the New-CsEdgeDomainPattern cmdlet, and each one of them will be saved in a variable. Then, the New-CsEdgeAllowList cmdlet will create a list of allowed domains from the variables. Finally, the Set-CsTenantFederationConfiguration cmdlet will be used. The domain we will work on will be (again) cc3b6a4e-3b6b-4ad4-90be-6faa45d05642. The example on Technet (http://technet.microsoft.com/en-us/library/jj994023.aspx) will be used: $x = New-CsEdgeDomainPattern -Domain "contoso.com" $y = New-CsEdgeDomainPattern -Domain "fabrikam.com" $newAllowList = New-CsEdgeAllowList -AllowedDomain $x,$y Set-CsTenantFederationConfiguration -Tenant " cc3b6a4e-3b6b-4ad4-90be-6faa45d05642" -AllowedDomains $newAllowList The Get-CsOnlineUser cmdlet provides information about users enabled on Office 365. The result will show both users synced with Active Directory and users homed in the cloud. The command supports filters to limit the output; for example, the Get-CsOnlineUser -identity fab will gather information about the user that has alias = fab. This is an account synced from the on-premises Directory Services, so the value of the DirSyncEnabled parameter will be True. See also All the cmdlets of the Remote PowerShell for Lync Online are listed in the TechNet post Lync Online cmdlets at http://technet.microsoft.com/en-us/library/jj994021.aspx. This is the main source of details on the single statement. Introducing Lync in a hybrid scenario In a Lync hybrid deployment, we have the following: User accounts and related information homed in the on-premises Directory Services and replicated to Office 365. A part of our Lync users that consume on-premises resources and a part of them that use online (Office 365 / Lync Online) resources. The same (public) domain name used both online and on-premises (Lync-split DNS). Other Office 365 services and integration with other applications available to all our users, irrespective of where their Lync is provisioned. One way to define Lync hybrid configuration is by using an on-premises Lync deployment federated with an Office 365 / Lync Online tenant subscription. While it is not a perfect explanation, it gives us an idea of the scenario we are talking about. Not all the features of Lync Server 2013 (especially the ones related to Enterprise Voice) are available to Lync Online users. The previously mentioned motivations, along with others (due to company policies, compliance requirements, and so on), might recommend a hybrid deployment of Lync as the best available solution. What we have to clarify now is how to make those users on different deployments talk to each other, see each other's presence status, and so on. What we will see in this section is a high-level overview of the required steps. The Planning and configuring a hybrid deployment recipe will provide more details about the individual steps. The list of steps here is the one required to configure a hybrid deployment, starting from Lync on-premises. In the following sections, we will also see the opposite scenario (with our initial deployment in the cloud). How to do it... It is required to have an available Office 365 tenant configuration. Our subscription has to include Lync Online. We have to configure an Active Directory Federation Services (AD FS) server in our domain and make it available to the Internet using a public FQDN and an SSL certificate released from a third-party certification authority. Office 365 must be enabled to synchronize with our company's Directory Services, using Active Directory Sync. Our Office 365 tenant must be federated. The last step is to configure Lync for a hybrid deployment. There's more... One of the requirements for a hybrid distribution of Lync is an on-premises deployment of Lync Server 2013 or Lync Server 2010. For Lync Server 2010, it is required to have the latest available updates installed, both on the Front Ends and on the Edge servers. It is also required to have the Lync Server 2013 administrative tools installed on a separate server. More details about supported configuration are available on the TechNet post Planning for Lync Server 2013 hybrid deployments at http://technet.microsoft.com/en-us/library/jj205403.aspx. DNS SRV records for hybrid deployments, _sipfederationtls._tcp.<domain> and _sip._tls.<domain>, should point to the on-premises deployment. The lyncdiscover. <domain> record will point to the FQDN of the on-premises reverse proxy server. The _sip._tls. <domain> SRV record will resolve to the public IP of the Access Edge service of Lync on-premises. Depending on the kind of service we are using for Lync, Exchange, and SharePoint, only a part of the features related to the integration with the additional services might be available. For example, skills search is available only if we are using Lync and SharePoint on-premises. The following TechNet post Supported Lync Server 2013 hybrid configurations at http://technet.microsoft.com/en-us/library/jj945633.aspx offers a matrix of features / service deployment combinations. See also Interesting information about Lync Hybrid configuration is presented in sessions available on Channel9 and coming from the Lync Conference 2014 (Lync Online Hybrid Deep Dive at http://channel9.msdn.com/Events/Lync-Conference/Lync-Conference-2014/ONLI302) and from TechEd North America 2014 (Microsoft Lync Online Hybrid Deep Dive at http://channel9.msdn.com/Events/TechEd/NorthAmerica/2014/OFC-B341#fbid=). Planning and configuring a hybrid deployment The planning phase for a hybrid deployment starts from a simple consideration: do we have an on-premises deployment of Lync Server? If the previously mentioned scenario is true, do we want to move users to the cloud or vice versa? Although the first situation is by far the most common, we have to also consider the case in which we have our first deployment in the cloud. How to do it... This step is all that is required for the scenario that starts from Lync Online. We have to completely deploy our Lync on-premises. Establish a remote PowerShell session with Office 365. Use the shared SIP address cmdlet Set-CsTenantFederationConfiguration -SharedSipAddressSpace $True to enable Office 365 to use a Shared Session Initiation Protocol (SIP) address space with our on-premises deployment. To verify this, we can use the Get-CsTenantFederationConfiguration command. The SharedSipAddressSpace value should be set to True. All the following steps are for the scenario that starts from the on-premises Lync deployment. After we have subscribed with a tenant, the first step is to add the public domain we use for our Lync users to Office 365 (so that we can split it on the two deployments). To access the Office 365 portal, select Domains. The next step is Specify a domain name and confirm ownership. We will be required to type a domain name. If our domain is hosted on some specific providers (such as GoDaddy), the verification process can be automated, or we have to proceed manually. The process requires to add one DNS record (TXT or MX), like the ones shown in the following screenshot: If we need to check our Office 365 and on-premises deployments before continuing with the hybrid deployment, we can use the Setup Assistant for Office 365. The tool is available inside the Office 365 portal, but we have to launch it from a domain-joined computer (the login must be performed with the domain administrative credentials). In the Setup menu, we have a Quick Start and an Extend Your Setup option (we have to select the second one). The process can continue installing an app or without software installation, as shown in the following screenshot: The app (which makes the assessment of the existing deployment easier) is installed by selecting Next in the previous screen (it requires at least Windows 7 with Service Pack 1, .NET Framework 3.5, and PowerShell 2.0). Synchronization with the on-premises Active Directory is required. This last step federates Lync Server 2013 with Lync Online to allow communication between our users. The first cmdlet to use is Set-CSAccessEdgeConfiguration -AllowOutsideUsers 1 -AllowFederatedUsers 1 -UseDnsSrvRouting -EnablePartnerDiscovery 1. Note that the -EnablePartnerDiscovery parameter is required. Setting it to 1 enables automatic discovery of federated partner domains. It is possible to set it to 0. The second required cmdlet is New-CSHostingProvider -Identity LyncOnline -ProxyFqdn "sipfed.online.lync.com" -Enabled $true -EnabledSharedAddressSpace $true -HostsOCSUsers $true –VerificationLevel UseSourceVerification -IsLocal $false -AutodiscoverUrl https://webdir.online.lync.com/Autodiscover/AutodiscoverService.svc/root. The result of the commands is shown in the following screenshot: If Lync Online is already defined, we have to use the Set- CSHostingProvider cmdlet, or we can remove it (Remove-CsHostingProvider -Identity LyncOnline) and then create it using the previously mentioned cmdlet. There's more... In the Lync hybrid scenario, users created in the on-premises directory are replicated to the cloud, while users generated in the cloud will not be replicated on-premises. Lync Online users are managed using the Office 365 portal, while the users on-premises are managed using the usual tools (Lync Control Panel and Lync Management Shell). Moving users to the cloud By moving users from Lync on-premises to the cloud, we will lose some of the parameters. The operation requires the Lync administrative tools and the PowerShell module for Lync Online to be installed on the same computer. If we install the module for Lync Online before the administrative tools for Lync 2013 Server, the OCSCore.msi file overwrites the LyncOnlineConnector.ps1 file, and New-CsOnlineSession will require a -TargetServer parameter. In this situation, we have to reinstall the Lync Online module (see the following post on the Microsoft support site at http://support.microsoft.com/kb/2955287). Getting ready Remember that to move the user to Lync Online, they must be enabled for both Lync Server on-premises and Lync Online (so we have to assign the user a license for Lync Online by using the Office 365 portal). Users with no assigned licenses will show the error Move-CsUser : HostedMigration fault: Error=(507), Description=(User must has an assigned license to use Lync Online. For more details, refer to the Microsoft support site at http://support.microsoft.com/kb/2829501. How to do it... Open a new Lync Management Shell session and launch the remote session on Office 365 with the cmdlets' sequence we saw earlier. We have to add the –AllowClobber parameter so that the Lync Online module's cmdlets are able to overwrite the corresponding Lync Management Shell cmdlets: $credential = Get-Credential $session = New-CsOnlineSession -Credential $credential Import-PSSession $session -AllowClobber Open the Lync Admin Center (as we have seen in the dedicated section) by going to Service settings | Lync | Manage settings in the Lync Admin Center, and copy the first part of the URL, for example, https://admin0e.online.lync.com. Add the following string to the previous URL /HostedMigration/hostedmigrationservice.svc (in our example, the result will be https://admin0a.online.lync.com/HostedMigration/hostedmigrationservice.svc). The following cmdlet will move users from Lync on-premises to Lync Online. The required parameters are the identity of the Lync user and the URL that we prepared in step 2. The user identity is fabrizio.volpe@absoluteuc.biz: Move-CsUser -Identity fabrizio.volpe@absoluteuc.biz –Target sipfed.online.lync.com -Credential $creds -HostedMigrationOverrideUrl https://admin0e.online.lync.com/HostedMigration/hostedmigrationservice.sVc Usually, we are required to insert (again) the Office 365 administrative credentials, after which we will receive a warning about the fact that we are moving our user to a different version of the service, like the one in the following screenshot: See the There's more... section of this recipe for details about user information that is migrated to Lync Online. We are able to quickly verify whether the user has moved to Lync Online by using the Get-CsUser | fl DisplayName,HostingProvider,RegistrarPool,SipAddress command. On-premises HostingProvider is equal to SRV: and RegistrarPool is madhatter.wonderland.lab (the name of the internal Lync Front End). Lync Online values are HostingProvider : sipfed.online.lync.com, and leave RegistrarPool empty, as shown in the following screenshot (the user Fabrizio is homed on-premises, while the user Fabrizio volpe is homed on the cloud): There's more... If we plan to move more than one user, we have to add a selection and pipe it before the cmdlet we have already used, removing the –identity parameter. For example, to move all users from an Organizational Unit (OU), (for example, the LyncUsers in the Wonderland.Lab domain) to Lync Online, we can use Get-CsUser -OU "OU=LyncUsers,DC=wonderland,DC=lab"| Move-CsUser -Target sipfed.online.lync.com -Credential $creds -HostedMigrationOverrideUrl https://admin0e.online.lync.com/HostedMigration/hostedmigrationservice.sVc. We are also able to move users based on a parameter to match using the Get-CsUser –Filter cmdlet. As we mentioned earlier, not all the user information is migrated to Lync Online. Migration contact list, groups, and access control lists are migrated, while meetings, contents, and schedules are lost. We can use the Lync Meeting Update Tool to update the meeting links (which have changed when our user's home server has changed) and automatically send updated meeting invitations to participants. There is a 64-bit version (http://www.microsoft.com/en-us/download/details.aspx?id=41656) and a 32-bit version (http://www.microsoft.com/en-us/download/details.aspx?id=41657) of the previously mentioned tool. Moving users back on-premises It is possible to move back users that have been moved from the on-premises Lync deployment to the cloud, and it is also possible to move on-premises users that have been defined and enabled directly in Office 365. In the latter scenario, it is important to create the user also in the on-premises domain (Directory Service). How to do it… The Lync Online user must be created in the Active Directory (for example, I will define the BornOnCloud user that already exists in Office 365). The user must be enabled in the on-premises Lync deployment, for example, using the Lync Management Shell with the following cmdlet: Enable-CsUser -Identity "BornOnCloud" -SipAddress "SIP:BornOnCloud@absoluteuc.biz" -HostingProviderProxyFqdn "sipfed.online.lync.com" Sync the Directory Services. Now, we have to save our Office 365 administrative credentials in a $cred = Get-Credential variable and then move the user from Lync Online to the on-premises Front End using the Lync Management Shell (the -HostedMigrationOverrideURL parameter has the same value that we used in the previous section): Move-CsUser -Identity BornOnCloud@absoluteuc.biz -Target madhatter.wonderland.lab -Credential $cred -HostedMigrationOverrideURL https://admin0e.online.lync.com/HostedMigration/hostedmigrationservice.svc The Get-CsUser | fl DisplayName,HostingProvider,RegistrarPool,SipAddress cmdlet is used to verify whether the user has moved as expected. See also Guy Bachar has published an interesting post on his blog Moving Users back to Lync on-premises from Lync Online (http://guybachar.wordpress.com/2014/03/31/moving-users-back-to-lync-on-premises-from-lync-online/), where he shows how he solved some errors related to the user motion by modifying the HostedMigrationOverrideUrl parameter. Debugging Lync Online issues Getting ready When moving from an on-premises solution to a cloud tenant, the first aspect we have to accept is that we will not have the same level of control on the deployment we had before. The tools we will list are helpful in resolving issues related to Lync Online, but the level of understanding on an issue they give to a system administrator is not the same we have with tools such as Snooper or OCSLogger. Knowing this, the more users we will move to the cloud, the more we will have to use the online instruments. How to do it… The Set up Lync Online external communications site on Microsoft Support (http://support.microsoft.com/common/survey.aspx?scid=sw;en;3592&showpage=1) is a guided walk-through that helps in setting up communication between our Lync Online users and external domains. The tool provides guidelines to assist in the setup of Lync Online for small to enterprise businesses. As you can see in the following screenshot, every single task is well explained: The Remote Connectivity Analyzer (RCA) (https://testconnectivity.microsoft.com/) is an outstanding tool to troubleshoot both Lync on-premises and Lync Online. The web page includes tests to analyze common errors and misconfigurations related to Microsoft services such as Exchange, Lync, and Office 365. To test different scenarios, it is necessary to use various network protocols and ports. If we are working on a firewall-protected network, using the RCA, we are also able to test services that are not directly available to us. For Lync Online, there are some tests that are especially interesting; in the Office 365 tab, the Office 365 General Tests section includes the Office 365 Lync Domain Name Server (DNS) Connectivity Test and the Office 365 Single Sign-On Test, as shown in the following screenshot: The Single Sign-On test is really useful in a scenario. The test requires our domain username and password, both synced with the on-premises Directory Services. The steps include searching the FQDN of our AD FS server on an Internet DNS, verifying the certificate and connectivity, and then validating the token that contains the credentials. The Client tab offers to download the Microsoft Connectivity Analyzer Tool and the Microsoft Lync Connectivity Analyzer Tool, which we will see in the following two dedicated steps: The Microsoft Connectivity Analyzer Tool makes many of the tests we see in the RCA available on our desktop. The list of prerequisites is provided in the article Microsoft Connectivity Analyzer Tool (http://technet.microsoft.com/library/jj851141(v=exchg.80).aspx), and includes Windows Vista/Windows 2008 or later versions of the operating system, .NET Framework 4.5, and an Internet browser, such as Internet Explorer, Chrome, or Firefox. For the Lync tests, a 64-bit operating system is mandatory, and the UCMA runtime 4.0 is also required (it is part of Lync Server 2013 setup, and is also available for download at http://www.microsoft.com/en-us/download/details.aspx?id=34992). The tools propose ways to solve different issues, and then, they run the same tests available on the RCA site. We are able to save the results in an HTML file. The Microsoft Lync Connectivity Analyzer Tool is dedicated to troubleshooting the clients for mobile devices (the Lync Windows Store app and Lync apps). It tests all the required configurations, including autodiscover and webticket services. The 32-bit version is available at http://www.microsoft.com/en-us/download/details.aspx?id=36536, while the 64-bit version can be downloaded from http://www.microsoft.com/en-us/download/details.aspx?id=36535. .NET Framework 4.5 is required. The tool itself requires a few configuration parameters; we have to insert the user information that we usually add in the Lync app, and we have to use a couple of drop-down menus to describe the scenario we are testing (on-premises or Internet, and the kind of client we are going to test). The Show drop-down menu enables us to look not only at a summary of the test results but also at the detailed information. The detailed view includes all the information and requests sent and received during the test, with the FQDN included in the answer ticket from our services, and so on, as shown in the following screenshot: The Troubleshooting Lync Online sign-in post is a support page, available in two different versions (admins and users), and is a walk-through to help admins (or users) to troubleshoot login issues. The admin version is available at http://support.microsoft.com/common/survey.aspx?scid=sw;en;3695&showpage=1, while the user version is available at http://support.microsoft.com/common/survey.aspx?scid=sw;en;3719&showpage=1. Based on our answers to the different scenario questions, the site will propose to information or solution steps. The following screenshot is part of the resolution for the log-I issues of a company that has an enterprise subscription with a custom domain: The Office 365 portal includes some information to help us monitor our Lync subscription. In the Service Health menu, navigate to Service Health; we have a list of all the incidents and service issues of the past days. In the Reports menu, we have statistics about our Office 365 consumption, including Lync. In the following screenshot, we can see the previously mentioned pages: There's more... One interesting aspect of the Microsoft Lync Connectivity Analyzer Tool that we have seen is that it enables testing for on-premises or Office 365 accounts (both testing from inside our network and from the Internet). The previously mentioned capability makes it a great tool to troubleshoot the configuration for Lync on the mobile devices that we have deployed in our internal network. This setup is usually complex, including hair-pinning and split DNS, so the diagnostic is important to quickly find misconfigured services. See also The Troubleshooting Lync Sign-in Errors (Administrators) page on Office.com at http://office.microsoft.com/en-001/communicator-help/troubleshooting-lync-sign-in-errors-administrators-HA102759022.aspx contains a list of messages related to sign-in errors with a suggested solution or a link to additional external resources. Summary In this article, we have learned about managing Lync 2013 and Lync Online and using Lync Online Remote PowerShell and Lync Online cmdlets. Resources for Article: Further resources on this subject: Adding Dialogs [article] Innovation of Communication and Information Technologies [article] Choosing Lync 2013 Clients [article]

In this article by John Horton, author of the book Learning Java by Building Android Games, we will learn how to set up our development environment by installing JDK and Android Studio. We will also learn how to create a new game activity and layout the same on a game screen UI. (For more resources related to this topic, see here.) Setting up our development environment The first thing we need to do is prepare our PC to develop for Android using Java. Fortunately, this is made quite simple for us. The next two tutorials have Windows-specific instructions and screenshots. However, it shouldn't be too difficult to vary the steps slightly to suit Mac or Linux. All we need to do is: Install a software package called the Java Development Kit (JDK), which allows us to develop in Java. Install Android Studio, a program designed to make Android development fast and easy. Android Studio uses the JDK and some other Android-specific tools that automatically get installed when we install Android Studio. Installing the JDK The first thing we need to do is get the latest version of the JDK. To complete this guide, perform the following steps: You need to be on the Java website, so visit http://www.oracle.com/technetwork/java/javase/downloads/index.html. Find the three buttons shown in the following screenshot and click on the one that says JDK (highlighted). They are on the right-hand side of the web page. Click on the DOWNLOAD button under the JDK option: You will be taken to a page that has multiple options to download the JDK. In the Product/File description column, you need to click on the option that matches your operating system. Windows, Mac, Linux and some other less common options are all listed. A common question here is, "do I have 32- or 64-bit windows?". To find out, right-click on your My Computer (This PC on Windows 8) icon, click on the Properties option, and look under the System heading in the System type entry, as shown in the following screenshot: Click on the somewhat hidden Accept License Agreement checkbox: Now click on the download option for your OS and system type as previously determined. Wait for the download to finish. In your Downloads folder, double-click on the file you just downloaded. The latest version at time of writing this for a 64-bit Windows PC was jdk-8u5-windows-x64. If you are using Mac/Linux or have a 32-bit OS, your filename will vary accordingly. In the first of several install dialogs, click on the Next button and you will see the next dialog box: Accept the defaults shown in the previous screenshot by clicking on Next. In the next dialog box, you can accept the default install location by clicking on Next. Next is the last dialog of the Java installer. Click on Close. The JDK is now installed. Next we will make sure that Android Studio is able to use the JDK. Right-click on your My Computer (This PC on Windows 8) icon and navigate to Properties | Advanced system settings | Environment variables | New (under System variables, not under User variables). Now you can see the New System Variable dialog, as shown in the following screenshot: Type JAVA_HOME for Variable name and enter C:Program FilesJavajdk1.8.0_05 for the Variable value field. If you installed the JDK somewhere else, then the file path you enter in the Variable value: field will need to point to wherever you put it. Your exact file path will likely have a different ending to match the latest version of Java at the time you downloaded it. Click on OK to save your new settings. Now click on OK again to clear the Advanced system settings dialog. Now we have the JDK installed on our PC. We are about half way towards starting to learn Java programming, but we need a friendly way to interact with the JDK and to help us make Android games in Java. Android Studio We learned that Android Studio is a tool that simplifies Android development and uses the JDK to allow us to write and build Java programs. There are other tools you can use instead of Android Studio. There are pros and cons in them all. For example, another extremely popular option is Eclipse. And as with so many things in programming, a strong argument can be made as to why you should use Eclipse instead of Android Studio. I use both, but what I hope you will love about Android Studio are the following elements: It is a very neat and, despite still being under development, a very refined and clean interface. It is much easier to get started compared to Eclipse because several Android tools that would otherwise need to be installed separately are already included in the package. Android Studio is being developed by Google, based on another product called IntelliJ IDEA. There is a chance it will be the standard way to develop Android in the not-too-distant future. If you want to use Eclipse, that's fine. However, some the keyboard shortcuts and user interface buttons will obviously be different. If you do not have Eclipse installed already and have no prior experience with Eclipse, then I even more strongly recommend you to go ahead with Android Studio. Installing Android Studio So without any delay, let's get Android Studio installed and then we can begin our first game project. To do this, let's visit https://developer.android.com/sdk/installing/studio.html. Click on the button labeled Download Android Studio to start the Android studio download. This will take you to another web page with a very similar-looking button to the one you just clicked on. Accept the license by checking in the checkbox, commence the download by clicking on the button labeled Download Android Studio for Windows, and wait for the download to complete. The exact text on the button will probably vary depending on the current latest version. In the folder in which you just downloaded Android Studio, right-click on the android-studio-bundle-135.12465-windows.exe file and click on Run as administrator. The end of your filename will vary depending upon the version of Android Studio and your operating system. When asked if you want to Allow the following program from an unknown publisher to make changes to your computer, click on Yes. On the next screen, click on Next. On the screen shown in the following screenshot, you can choose which users of your PC can use Android Studio. Choose whatever is right for you as all options will work, and then click on Next: In the next dialog, leave the default settings and then click on Next. Then on the Choose start menu folder dialog box, leave the defaults and click on Install. On the Installation complete dialog, click on Finish to run Android Studio for the first time. The next dialog is for users who have already used Android Studio, so assuming you are a first time user, select the I do not have a previous version of Android Studio or I do not want to import my settings checkbox, and then click on OK: That was the last piece of software we needed. Math game – asking a question Now that we have all that knowledge under our belts, we can use it to improve our math game. First, we will create a new Android activity to be the actual game screen as opposed to the start menu screen. We will then use the UI designer to lay out a simple game screen so that we can use our Java skills with variables, types, declaration, initialization, operators, and expressions to make our math game generate a question for the player. We can then link the start menu and game screens together with a push button. Creating the new game activity We will first need to create a new Java file for the game activity code and a related layout file to hold the game activity UI. Run Android Studio and select your Math Game Chapter 2 project. It might have been opened by default. Now we will create the new Android activity that will contain the actual game screen, which will run when the player taps the Play button on our main menu screen. To create a new activity, we now need another layout file and another Java file. Fortunately Android Studio will help us do this. To get started with creating all the files we need for a new activity, right-click on the src folder in the Project Explorer and then go to New | Activity. Now click on Blank Activity and then on Next. We now need to tell Android Studio a little bit about our new activity by entering information in the above dialog box. Change the Activity Name field to GameActivity. Notice how the Layout Name field is automatically changed for us to activity_game and the Title field is automatically changed to GameActivity. Click on Finish. Android Studio has created two files for us and has also registered our new activity in a manifest file, so we don't need to concern ourselves with it. If you look at the tabs at the top of the editor window, you will see that GameActivity.java has been opened up ready for us to edit, as shown in the following screenshot: Ensure that GameActivity.java is active in the editor window by clicking on the GameActivity.java tab shown previously. Here, we can see the code that is unnecessary. If we remove it, then it will make our working environment simpler and cleaner. We will simply use the code from MainActivity.java as a template for GameActivity.java. We can then make some minor changes. Click on the MainActivity.java tab in the editor window. Highlight all of the code in the editor window using Ctrl + A on the keyboard. Now copy all of the code in the editor window using the Ctrl + C on the keyboard. Now click on the GameActivity.java tab. Highlight all of the code in the editor window using Ctrl + A on the keyboard. Now paste the copied code and overwrite the currently highlighted code using Ctrl + V on the keyboard. Notice that there is an error in our code denoted by the red underlining as shown in the following screenshot. This is because we pasted the code referring to MainActivity in our file that is called GameActivity. Simply change the text MainActivity to GameActivity and the error will disappear. Take a moment to see if you can work out what other minor change is necessary, before I tell you. Remember that setContentView loads our UI design. Well what we need to do is change setContentView to load the new design (that we will build next) instead of the home screen design. Change setContentView(R.layout.activity_main); to setContentView(R.layout.activity_game);. Save your work and we are ready to move on. Note the Project Explorer where Android Studio puts the two new files it created for us. I have highlighted two folders in the next screenshot. In future, I will simply refer to them as our java code folder or layout files folder. You might wonder why we didn't simply copy and paste the MainActivity.java file to begin with and saved going through the process of creating a new activity? The reason is that Android Studio does things behind the scenes. Firstly, it makes the layout template for us. It also registers the new activity for use through a file we will see later, called AndroidManifest.xml. This is necessary for the new activity to be able to work in the first place. All things considered, the way we did it is probably the quickest. The code at this stage is exactly the same as the code for the home menu screen. We state the package name and import some useful classes provided by Android: package com.packtpub.mathgamechapter3a.mathgamechapter3a;   import android.app.Activity; import android.os.Bundle; We create a new activity, this time called GameActivity: public class GameActivity extends Activity { Then we override the onCreate method and use the setContentView method to set our UI design as the contents of the player's screen. Currently, however, this UI is empty: super.onCreate(savedInstanceState);setContentView(R.layout.activity_main); We can now think about the layout of our actual game screen. Laying out the game screen UI As we know, our math game will ask questions and offer the player some multiple choices to choose answers from. There are lots of extra features we could add, such as difficulty levels, high scores, and much more. But for now, let's just stick to asking a simple, predefined question and offering a choice of three predefined possible answers. Keeping the UI design to the bare minimum suggests a layout. Our target UI will look somewhat like this: The layout is hopefully self-explanatory, but let's ensure that we are really clear; when we come to building this layout in Android Studio, the section in the mock-up that displays 2 x 2 is the question and will be made up of three text views (both numbers, and the = sign is also a separate view). Finally, the three options for the answer are made up of Button layout elements. This time, as we are going to be controlling them using our Java code, there are a few extra things we need to do to them. So let's go through it step by step: Open the file that will hold our game UI in the editor window. Do this by double-clicking on activity_game.xml. This is located in our UI layout folder, which can be found in the project explorer. Delete the Hello World TextView, as it is not required. Find the Large Text element on the palette. It can be found under the Widgets section. Drag three elements onto the UI design area and arrange them near the top of the design as shown in the next screenshot. It does not have to be exact; just ensure that they are in a row and not overlapping, as shown in the following screenshot: Notice in the Component Tree window that each of the three TextViews has been assigned a name automatically by Android Studio. They are textView , textView2, and textView3: Android Studio refers to these element names as an id. This is an important concept that we will be making use of. So to confirm this, select any one of the textViews by clicking on its name (id), either in the component tree as shown in the preceding screenshot or directly on it in the UI designer shown previously. Now look at the Properties window and find the id property. You might need to scroll a little to do this: Notice that the value for the id property is textView. It is this id that we will use to interact with our UI from our Java code. So we want to change all the IDs of our TextViews to something useful and easy to remember. If you look back at our design, you will see that the UI element with the textView id is going to hold the number for the first part of our math question. So change the id to textPartA. Notice the lowercase t in text, the uppercase P in Part, and the uppercase A. You can use any combination of cases and you can actually name the IDs anything you like. But just as with naming conventions with Java variables, sticking to conventions here will make things less error-prone as our program gets more complicated. Now select textView2 and change id to textOperator. Select the element currently with id textView3 and change it to textPartB. This TextView will hold the later part of our question. Now add another Large Text from the palette. Place it after the row of the three TextViews that we have just been editing. This Large Text will simply hold our equals to sign and there is no plan to ever change it. So we don't need to interact with it in our Java code. We don't even need to concern ourselves with changing the ID or knowing what it is. If this situation changed, we could always come back at a later time and edit its ID. However, this new TextView currently displays Large Text and we want it to display an equals to sign. So in the Properties window, find the text property and enter the value =. We have changed the text property, and you might also like to change the text property for textPartA, textPartB, and textOperator. This is not absolutely essential because we will soon see how we can change it via our Java code; however, if we change the text property to something more appropriate, then our UI designer will look more like it will when the game runs on a real device. So change the text property of textPartA to 2, textPartB to 2, and textOperator to x. Your UI design and Component tree should now look like this: For the buttons to contain our multiple choice answers, drag three buttons in a row, below the = sign. Line them up neatly like our target design. Now, just as we did for the TextViews, find the id properties of each button, and from left to right, change the id properties to buttonChoice1, buttonChoice2, and buttonChoice3. Why not enter some arbitrary numbers for the text property of each button so that the designer more accurately reflects what our game will look like, just as we did for our other TextViews? Again, this is not absolutely essential as our Java code will control the button appearance. We are now actually ready to move on. But you probably agree that the UI elements look a little lost. It would look better if the buttons and text were bigger. All we need to do is adjust the textSize property for each TextView and for each Button. Then, we just need to find the textSize property for each element and enter a number with the sp syntax. If you want your design to look just like our target design from earlier, enter 70sp for each of the TextView textSize properties and 40sp for each of the Buttons textSize properties. When you run the game on your real device, you might want to come back and adjust the sizes up or down a bit. But we have a bit more to do before we can actually try out our game. Save the project and then we can move on. As before, we have built our UI. This time, however, we have given all the important parts of our UI a unique, useful, and easy to identify ID. As we will see we are now able to communicate with our UI through our Java code. Summary In this article, we learned how to set up our development environment by installing JDK and Android Studio. In addition to this, we also learned how to create a new game activity and layout the same on a game screen UI. Resources for Article: Further resources on this subject: Sound Recorder for Android [article] Reversing Android Applications [article] 3D Modeling [article]

In this article by Massimiliano Pippi, author of the book Python for Google App Engine, in this article, you will learn how to write a web application and seeing the platform in action. Web applications commonly provide a set of features such as user authentication and data storage. App Engine provides the services and tools needed to implement such features. (For more resources related to this topic, see here.) In this article, we will see: Details of the webapp2 framework How to authenticate users Storing data on Google Cloud Datastore Building HTML pages using templates Experimenting on the Notes application To better explore App Engine and Cloud Platform capabilities, we need a real-world application to experiment on; something that's not trivial to write, with a reasonable list of requirements. A good candidate is a note-taking application; we will name it Notes. Notes enable the users to add, remove, and modify a list of notes; a note has a title and a body of text. Users can only see their personal notes, so they must authenticate before using the application. The main page of the application will show the list of notes for logged-in users and a form to add new ones. The code from the helloworld example is a good starting point. We can simply change the name of the root folder and the application field in the app.yaml file to match the new name we chose for the application, or we can start a new project from scratch named notes. Authenticating users The first requirement for our Notes application is showing the home page only to users who are logged in and redirect others to the login form; the users service provided by App Engine is exactly what we need and adding it to our MainHandler class is quite simple: import webapp2 from google.appengine.api import users class MainHandler(webapp2.RequestHandler): def get(self): user = users.get_current_user() if user is not None: self.response.write('Hello Notes!') else: login_url = users.create_login_url(self.request.uri) self.redirect(login_url) app = webapp2.WSGIApplication([ ('/', MainHandler) ], debug=True) The user package we import on the second line of the previous code provides access to users' service functionalities. Inside the get() method of the MainHandler class, we first check whether the user visiting the page has logged in or not. If they have, the get_current_user() method returns an instance of the user class provided by App Engine and representing an authenticated user; otherwise, it returns None as output. If the user is valid, we provide the response as we did before; otherwise, we redirect them to the Google login form. The URL of the login form is returned using the create_login_url() method, and we call it, passing as a parameter the URL we want to redirect users to after a successful authentication. In this case, we want to redirect users to the same URL they are visiting, provided by webapp2 in the self.request.uri property. The webapp2 framework also provides handlers with a redirect() method we can use to conveniently set the right status and location properties of the response object so that the client browsers will be redirected to the login page. HTML templates with Jinja2 Web applications provide rich and complex HTML user interfaces, and Notes is no exception but, so far, response objects in our applications contained just small pieces of text. We could include HTML tags as strings in our Python modules and write them in the response body but we can imagine how easily it could become messy and hard to maintain the code. We need to completely separate the Python code from HTML pages and that's exactly what a template engine does. A template is a piece of HTML code living in its own file and possibly containing additional, special tags; with the help of a template engine, from the Python script, we can load this file, properly parse special tags, if any, and return valid HTML code in the response body. App Engine includes in the Python runtime a well-known template engine: the Jinja2 library. To make the Jinja2 library available to our application, we need to add this code to the app.yaml file under the libraries section: libraries: - name: webapp2 version: "2.5.2" - name: jinja2 version: latest We can put the HTML code for the main page in a file called main.html inside the application root. We start with a very simple page: <!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title>Notes</title> </head> <body> <div class="container"> <h1>Welcome to Notes!</h1> <p> Hello, <b>{{user}}</b> - <a href="{{logout_url}}">Logout</a> </p> </div> </body> </html> Most of the content is static, which means that it will be rendered as standard HTML as we see it but there is a part that is dynamic and whose content depend on which data will be passed at runtime to the rendering process. This data is commonly referred to as template context. What has to be dynamic is the username of the current user and the link used to log out from the application. The HTML code contains two special elements written in the Jinja2 template syntax, {{user}} and {{logout_url}}, that will be substituted before the final output occurs. Back to the Python script; we need to add the code to initialize the template engine before the MainHandler class definition: import os import jinja2 jinja_env = jinja2.Environment( loader=jinja2.FileSystemLoader(os.path.dirname(__file__))) The environment instance stores engine configuration and global objects, and it's used to load templates instances; in our case, instances are loaded from HTML files on the filesystem in the same directory as the Python script. To load and render our template, we add the following code to the MainHandler.get() method: class MainHandler(webapp2.RequestHandler): def get(self): user = users.get_current_user() if user is not None: logout_url = users.create_logout_url(self.request.uri) template_context = { 'user': user.nickname(), 'logout_url': logout_url, } template = jinja_env.get_template('main.html') self.response.out.write( template.render(template_context)) else: login_url = users.create_login_url(self.request.uri) self.redirect(login_url) Similar to how we get the login URL, the create_logout_url() method provided by the user service returns the absolute URI to the logout procedure that we assign to the logout_url variable. We then create the template_context dictionary that contains the context values we want to pass to the template engine for the rendering process. We assign the nickname of the current user to the user key in the dictionary and the logout URL string to the logout_url key. The get_template() method from the jinja_env instance takes the name of the file that contains the HTML code and returns a Jinja2 template object. To obtain the final output, we call the render() method on the template object passing in the template_context dictionary whose values will be accessed, specifying their respective keys in the HTML file with the template syntax elements {{user}} and {{logout_url}}. Handling forms The main page of the application is supposed to list all the notes that belong to the current user but there isn't any way to create such notes at the moment. We need to display a web form on the main page so that users can submit details and create a note. To display a form to collect data and create notes, we put the following HTML code right below the username and the logout link in the main.html template file: {% if note_title %} <p>Title: {{note_title}}</p> <p>Content: {{note_content}}</p> {% endif %} <h4>Add a new note</h4> <form action="" method="post"> <div class="form-group"> <label for="title">Title:</label> <input type="text" id="title" name="title" /> </div> <div class="form-group"> <label for="content">Content:</label> <textarea id="content" name="content"></textarea> </div> <div class="form-group"> <button type="submit">Save note</button> </div> </form> Before showing the form, a message is displayed only when the template context contains a variable named note_title. To do this, we use an if statement, executed between the {% if note_title %} and {% endif %} delimiters; similar delimiters are used to perform for loops or assign values inside a template. The action property of the form tag is empty; this means that upon form submission, the browser will perform a POST request to the same URL, which in this case is the home page URL. As our WSGI application maps the home page to the MainHandler class, we need to add a method to this class so that it can handle POST requests: class MainHandler(webapp2.RequestHandler): def get(self): user = users.get_current_user() if user is not None: logout_url = users.create_logout_url(self.request.uri) template_context = { 'user': user.nickname(), 'logout_url': logout_url, } template = jinja_env.get_template('main.html') self.response.out.write( template.render(template_context)) else: login_url = users.create_login_url(self.request.uri) self.redirect(login_url) def post(self): user = users.get_current_user() if user is None: self.error(401) logout_url = users.create_logout_url(self.request.uri) template_context = { 'user': user.nickname(), 'logout_url': logout_url, 'note_title': self.request.get('title'), 'note_content': self.request.get('content'), } template = jinja_env.get_template('main.html') self.response.out.write( template.render(template_context)) When the form is submitted, the handler is invoked and the post() method is called. We first check whether a valid user is logged in; if not, we raise an HTTP 401: Unauthorized error without serving any content in the response body. Since the HTML template is the same served by the get() method, we still need to add the logout URL and the user name to the context. In this case, we also store the data coming from the HTML form in the context. To access the form data, we call the get() method on the self.request object. The last three lines are boilerplate code to load and render the home page template. We can move this code in a separate method to avoid duplication: def _render_template(self, template_name, context=None): if context is None: context = {} template = jinja_env.get_template(template_name) return template.render(context) In the handler class, we will then use something like this to output the template rendering result: self.response.out.write( self._render_template('main.html', template_context)) We can try to submit the form and check whether the note title and content are actually displayed above the form. Summary Thanks to App Engine, we have already implemented a rich set of features with a relatively small effort so far. We have discovered some more details about the webapp2 framework and its capabilities, implementing a nontrivial request handler. We have learned how to use the App Engine users service to provide users authentication. We have delved into some fundamental details of Datastore and now we know how to structure data in grouped entities and how to effectively retrieve data with ancestor queries. In addition, we have created an HTML user interface with the help of the Jinja2 template library, learning how to serve static content such as CSS files. Resources for Article: Further resources on this subject: Machine Learning in IPython with scikit-learn [Article] Introspecting Maya, Python, and PyMEL [Article] Driving Visual Analyses with Automobile Data (Python) [Article]

In this article by Jorge Jordán, author of the book Cocos2d Game Development Blueprints, we will see how to run the newly created project in Xcode. (For more resources related to this topic, see here.) Click on Run at the top-left of the Xcode window and it will run the project in the iOS Simulator, which defaults to an iOS 6.1 iPhone: Voilà! You've just built your first Hello World example with Cocos2d v3, but before going further, let's take a look at the code to understand how it works. We will be using iOS Simulator to run the game unless otherwise specified. Understanding the default project We are going to take an overview of the classes available in a new project, but don't worry if you don't understand everything; the objective of this section is just to get familiar with the look of a Cocos2d game. If you open the main.m class under the Supporting Files group, you will see: int main(int argc, char *argv[]) {    @autoreleasepool {        int retVal = UIApplicationMain(argc, argv, nil,         @"AppDelegate");        return retVal;    } } As you can see, the @autorelease block means that ARC is enabled by default on new Cocos2d projects so we don't have to worry about releasing objects or enabling ARC. ARC is the acronym for Automatic Reference Counting and it's a compiler iOS feature to provide automatic memory management of objects. It works by adding code at compile time, ensuring every object lives as long as necessary, but not longer. On the other hand, the block calls AppDelegate, a class that inherits from CCAppDelegate which implements the UIApplicationDelegate protocol. In other words, the starting point of our game and the place to set up our app is located in AppDelegate, like a typical iOS application. If you open AppDelegate.m, you will see the following method, which is called when the game has been launched: -(BOOL)application:(UIApplication *)applicationdidFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    [self setupCocos2dWithOptions:@{          CCSetupShowDebugStats: @(YES),    }];    return YES; } Here, the only initial configuration specified is to enable the debug stats, specifying the option CCSetupShowDebugStats: @(YES), that you can see in the previous block of code. The number on the top indicates the amount of draw calls and the two labels below are the time needed to update the frame and the frame rate respectively. The maximum frame rate an iOS device can have is 60 and it's a measure of the smoothness a game can attain: the higher the frame rate, the smoother the game. You will need to have the top and the bottom values in mind as the number of draw calls and the frame rate will let you know how efficient your game will be. The next thing to take care of is the startScene method: -(CCScene *)startScene {    // The initial scene will be GameScene    return [IntroScene scene]; } This method should be overriden to indicate the first scene we want to display in our game. In this case, it points to IntroScene where the init method looks like the following code: - (id)init {    // Apple recommends assigning self with super's return value    self = [super init];    if (!self) {        return(nil);      }    // Create a colored background (Dark Gray)    CCNodeColor *background = [CCNodeColor nodeWithColor:[CCColorcolorWithRed:0.2f green:0.2f blue:0.2f alpha:1.0f]];    [self addChild:background];    // Hello world    CCLabelTTF *label = [CCLabelTTF labelWithString:@"Hello World"fontName:@"Chalkduster" fontSize:36.0f];    label.positionType = CCPositionTypeNormalized;    label.color = [CCColor redColor];    label.position = ccp(0.5f, 0.5f); // Middle of screen    [self addChild:label];    // Helloworld scene button    CCButton *helloWorldButton = [CCButton buttonWithTitle:@"[Start ]" fontName:@"Verdana-Bold" fontSize:18.0f];    helloWorldButton.positionType = CCPositionTypeNormalized;    helloWorldButton.position = ccp(0.5f, 0.35f);    [helloWorldButton setTarget:self     selector:@selector(onSpinningClicked:)];    [self addChild:helloWorldButton];    // done    return self; } This code first calls the initialization method for the superclass IntroScene by sending the [super init] message. Then it creates a gray-colored background with a CCNodeColor class, which is basically a solid color node, but this background won't be shown until it's added to the scene, which is exactly what [self addChild:background] does. The red "Hello World" label you can see in the previous screenshot is an instance of the CCLabelTTF class, whose position will be centered on the screen thanks to label.position = ccp(0.5f, 0.5f). Cocos2d provides the cpp(coord_x, coord_y) method, which is a precompiler macro for CGPointMake and both can be used interchangeably. The last code block creates CCButton that will call onSpinningClicked once we click on it. This source code isn't hard at all, but what will happen when we click on the Start button? Don't be shy, go back to the iOS Simulator and find out! If you take a look at the onSpinningClicked method in IntroScene.m, you will understand what happened: - (void)onSpinningClicked:(id)sender {    // start spinning scene with transition    [[CCDirector sharedDirector] replaceScene:[HelloWorldScene     scene]        withTransition:[CCTransitiontransitionPushWithDirection:CCTransitionDirectionLeftduration:1.0f]]; } This code presents the HelloWorldScene scene replacing the current one (InitScene) and it's being done by pushing HelloWorldScene to the top of the scene stack and using a horizontal scroll transition that will last for 1.0 second. Let's take a look at the HelloWorldScene.m to understand the behavior we just experienced: @implementation HelloWorldScene {    CCSprite *_sprite; } - (id)init {    // Apple recommends assigning self with super's return value    self = [super init];    if (!self) {        return(nil);    }    // Enable touch handling on scene node    self.userInteractionEnabled = YES;    // Create a colored background (Dark Gray)    CCNodeColor *background = [CCNodeColor nodeWithColor:[CCColorcolorWithRed:0.2f green:0.2f blue:0.2f alpha:1.0f]];    [self addChild:background];    // Add a sprite    _sprite = [CCSprite spriteWithImageNamed:@"Icon-72.png"];    _sprite.position =     ccp(self.contentSize.width/2,self.contentSize.height/2);    [self addChild:_sprite];    // Animate sprite with action    CCActionRotateBy* actionSpin = [CCActionRotateByactionWithDuration:1.5f angle:360];    [_sprite runAction:[CCActionRepeatForeveractionWithAction:actionSpin]];    // Create a back button    CCButton *backButton = [CCButton buttonWithTitle:@"[ Menu ]"fontName:@"Verdana-Bold" fontSize:18.0f];    backButton.positionType = CCPositionTypeNormalized;    backButton.position = ccp(0.85f, 0.95f); // Top Right ofscreen    [backButton setTarget:self     selector:@selector(onBackClicked:)];    [self addChild:backButton];    // done    return self; } This piece of code is very similar to the one we saw in IntroScene.m, which is why we just need to focus on the differences. If you look at the top of the class, you can see how we are declaring a private instance for a CCSprite class, which is also a subclass of CCNode, and its main role is to render 2D images on the screen. The CCSprite class is one of the most-used classes in Cocos2d game development, as it provides a visual representation and a physical shape to the objects in view. Then, in the init method, you will see the instruction self.userInteractionEnabled = YES, which is used to enable the current scene to detect and manage touches by implementing the touchBegan method. The next thing to highlight is how we initialize a CCSprite class using an image, positioning it in the center of the screen. If you read a couple more lines, you will understand why the icon rotates as soon as the scene is loaded. We create a 360-degree rotation action thanks to CCRotateBy that will last for 1.5 seconds. But why is this rotation repeated over and over? This happens thanks to CCActionRepeatForever, which will execute the rotate action as long as the scene is running. The last piece of code in the init method doesn't need explanation as it creates a CCButton that will execute onBackClicked once clicked. This method replaces the scene HelloWorldScene with IntroScene in a similar way as we saw before, with only one difference: the transition happens from left to right. Did you try to touch the screen? Try it and you will understand why touchBegan has the following code: -(void) touchBegan:(UITouch *)touch withEvent:(UIEvent *)event {    CGPoint touchLoc = [touch locationInNode:self];    // Move our sprite to touch location    CCActionMoveTo *actionMove = [CCActionMoveToactionWithDuration:1.0f position:touchLoc];    [_sprite runAction:actionMove]; } This is one of the methods you need to implement to manage touch. The others are touchMoved, touchEnded, and touchCancelled. When the user begins touching the screen, the sprite will move to the registered coordinates thanks to a commonly used action: CCActionMoveto. This action just needs to know the position that we want to move our sprite to and the duration of the movement. Now that we have had an overview of the initial project code, it is time to go deeper into some of the classes we have shown. Did you realize that CCNode is the parent class of several classes we have seen? You will understand why if you keep reading. Summary In this article, we had our first contact with a Cocos2d project. We executed a new project and took an overview of it, understanding some of the classes that are part of this framework. Resources for Article: Further resources on this subject: Dragging a CCNode in Cocos2D-Swift [Article] Animations in Cocos2d-x [Article] Why should I make cross-platform games? [Article]

Advanced Programming and Control In this article by Gary Garber, author of the book Learning LEGO MINDSTORMS EV3, we will explore advanced controlling algorithms to use for sensor-based navigation and tracking. We will cover: Proportional distance control with the Ultrasonic Sensor Proportional distance control with the Infrared (IR) Sensor Line following with the Color Sensor Two-level control with the Color Sensor Proportional control with the Color Sensor Proportional integral derivative control Precise turning and course correction with the Gyro Sensor Beacon tracking with the IR sensor Triangulation with two IR beacons (For more resources related to this topic, see here.) Distance controller In this section, we will program the robot to gradually come to a stop using a proportional algorithm. In a proportional algorithm, the robot will gradually slow down as it approaches the desired stopping point. Before we begin, we need to attach a distance sensor to our robot. If you have the Home Edition, you will be using the IR sensor, whereas if you have the Educational Edition, you will use the Ultrasonic Sensor. Because these sensors use reflected beams (infrared light or sound), they need to be placed unobstructed by the other parts of the robot. You could either place the sensor high above the robot or well out in front of many parts of the robot. The design I have shown in the following screenshot allows you to place the sensor in front of the robot. If you are using the Ultrasonic Sensor for FIRST Lego League (a competition that uses a lot of sensor-based navigation) and trying to measure the distance to the border, you will find it is a good idea to place the sensor as low as possible. This is because the perimeter of the playing fields for FIRST LEGO League are made from 3- or 4-inch- high pieces of lumber. Infrared versus Ultrasonic We are going to start out with a simple program and will gradually add complexity to it. If you are using the Ultrasonic Sensor, it should be plugged into port 4, and this program is on the top line. If you are using the IR sensor, it should be plugged into port 1 and this program is at the bottom line. In this program, the robot moves forward until the Wait block tells it to stop 25 units from a wall or other barrier. You will find that the Ultrasonic Sensor can be set to stop in units of inches or centimeters. The Ultrasonic Sensor emits high-frequency sound waves (above the range of human hearing) and measures the time delay between the emission of the sound waves and when the reflection off an object is measured by the sensor. In everyday conditions, we can assume that the speed of sound is constant, and thus the Ultrasonic Sensor can give precise distance measurements to the nearest centimeter. In other programming languages, you could even use the Ultrasonic Sensor to transmit data between two robots. The IR sensor emits infrared light and has an IR-sensitive camera that measures the reflected light. The sensor reading does not give exact distance units because the strength of the signal depends on environmental factors such as the reflectivity of the surface. What the IR sensor loses in precision in proximity measurements, it makes up for in the fact that you can use it to track on the IR beacon, which is a source of infrared light. In other programming languages, you could actually use the IR sensor to track on sources of infrared light other than the beacon (such as humans or animals). In the following screenshot, we have a simple program that will tell the robot to stop a given distance from a barrier using a Wait for the sensor block. The program on the top of the screenshot uses the Ultrasonic Sensor, and the program on the bottom of the screenshot uses the IR sensor. You should only use the program for the sensor you are using. If you are downloading and executing the program from the Packt Publishing website, you should delete the program that you do not need. When you execute the program in the preceding screenshot, you will find that the robot only begins to stop at 25 units from the wall, but cannot stop immediately. To do this, the robot will need to slow down before it gets to the stopping point. Proportional algorithm In the next set of program, we create a loop called Slow Down. Inside this loop, readings from the Ultrasonic or Infrared proximity sensor block are sent to a Math block (to take the negative of the position values so that the robot moves forward) and then sent to the power input of a Move Steering block. We can have the loop end when it reaches our desired stopping distance as shown in the following screenshot: Instead of using the exact values of the output of the sensor block, we can use the difference between the actual position and the desired position to control the Move Steering block, as shown in the following screenshot. This difference is called the error. We call the desired position the setpoint. In the following screenshot, the setpoint is 20. The power is actually proportional to the error or the difference between the positions. When you execute this code, you will also find that if the robot is too close to the wall, it will run in reverse and back up from the wall. We are using an Advanced Math block in the following screenshot. You can see that we are writing a simple equation, -(a-b), into the block text field of the Advanced Math block: You may have also noticed that the robot moves very slowly as it approaches the stopping point. You can change this program by adding gain to the algorithm. If you multiply the difference by a larger factor, it will approach the stopping point quicker. When you execute this program, you will find that if you increase the gain too much, it will overshoot the stopping point and reverse direction. We can adjust these values using the Advanced Math block. We can type in any simple math function we need, as shown in the following screenshot. In this block, the value of a is the measured position, b is the setpoint position, and c is the gain. The equation can be seen in the following screenshot inside the block text field of the Advanced Math block: We can also define the desired gain and setpoint position using variables. We can create two Variable blocks called Gain and Set Point. We can write the value 3 to the Gain variable block and 20 to the Set Point variable block. Inside our loop, we can then read these variables and take the output of the Read Variable block and draw data wires into the Advanced Math block. The basic idea of the proportional algorithm is that the degree of correction needed is proportional to the error. So when our measured value is far from our goal, a large correction is applied. When our measured value is near our goal, only a small correction is applied. The algorithm also allows overcorrections. If the robot moves past the setpoint distance, it will back up. Depending on what you are trying to do, you will need to play around with various values for the gain variable. If the gain is too large, you will overshoot your goal and oscillate around it. If your gain is too small, you will never reach your goal. The response time of the microprocessor also affects the efficiency of the algorithm. You can experiment by inserting a Wait block into the loop and see how this affects the behavior of the robot. If we are merely using the distance sensor to approach a stationary object, then the proportional algorithm will suffice. However, if you were trying to maintain a given distance from a moving object (such as another robot), you might need a more complicated algorithm such as a Proportional Integral Derivative (PID) controller. Next we will build a line follower using the Color Sensor, which will use a PID controller. Line following using the Color Sensor When we are using the Color Sensor in Reflected Light Intensity mode, the sensor emits light and the robot measures the intensity of the reflected light. The brightness of the red LED in the sensor is a constant, but the intensity of the reflection will depend on the reflectivity of the surface, the angle of the sensor relative to the surface, and the distance of the sensor from the surface. If you shine the sensor at a surface, you will notice that a circle of light is generated. As you change the height of the sensor, the diameter of this circle will change because the light emitted from the LED diverges in a cone. As you increase the height, the size of the circle gets larger and the reflected intensity gets smaller. You might think you want the sensor to be as close as possible to the surface. Because there is a finite distance between the LED and the photo diode (which collects the light) of about 5.5 mm, it puts a constraint on the minimum diameter of your circle of light. Ideally, you want the circle of light to have a diameter of about 11 mm, which means placing the sensor about half of a centimeter above the tracking surface. For the caster-bot, you will need the sensor, an axle, two bushings, two long pins, a 5-mod beam, and two axle-pin connectors, as you can see in the following screenshot: You can assemble the sensor attachment in two steps. The sensor attachment settles into the holes in the caster attachment itself as you can see in the following screenshot. This placement is ideal as it allows the caster to do the steering while you do your line tracking. You can build the Color Sensor attachment in four steps. The Color Sensor attachment for the skid-bot will be the most complicated of our designs because we want the sensor to be in front of the robot and the skid is quite long. Again, we will need the pins, axles, bushings, and axle-pin connectors seen in the following screenshot: The Color Sensor attachment will connect directly to the EV3 brick. As you can see in the following screenshot, the attachment will be inserted from below the brick: Next I will describe the attachment for the tread-bot from the Educational kit. Because the tread-bot is slightly higher off the ground, we need to use some pieces such as the thin 1 x 4 mod lift arm that is a half mod in height. This extra millimeter in height can make a huge difference in the signal strength. The pins have trouble gripping the thin lift arm, so I like to use the pins with stop bushings to prevent the lift arm from falling off. The Light Sensor attachment is once again inserted into the underside of the EV3 brick as you can see in the following screenshot: The simplest of our Light Sensor attachments will be the tread-bot for the Home Edition, and you can build this in one step. Similarly, it attaches to the underside of the EV3 brick. Summary In this article, we explored advanced methods of navigations. We used both the Ultrasonic Sensor and the Infrared Sensor to measure distance with a proportional algorithm. Resources for Article: Further resources on this subject: eJOS – Unleashing EV3 [article] Proportional line follower (Advanced) [article] Making the Unit Very Mobile - Controlling Legged Movement [article]