How-To Tutorials

(For more resources related to this topic, see here.) Architecture overview In this section we will examine and compare the architectures of OpenCV and Emgu CV. OpenCV In the hello-world project, we already knew our code had something to do with the bin folder in the Emgu library that we installed. Those files are OpenCV DLLs, which have the filename starting with opencv_. So the Emgu CV users need to have some basic knowledge about OpenCV. OpenCV is broadly structured into five main components. Four of them are described in the following section: The first one is the CV component, which includes the algorithms about computer vision and basic image processing. All the methods for basic processes are found here. ML is short for Machine Learning, which contains popular machine learning algorithms with clustering tools and statistical classifiers. HighGUI is designed to construct user-friendly interfaces to load and store media data. CXCore is the most important one. This component provides all the basic data structures and contents. The components can be seen in the following diagram: The preceding structure map does not include CvAux, which contains many areas. It can be divided into two parts: defunct areas and experimental algorithms. CvAux is not particularly well documented in the Wiki, but it covers many features. Some of them may migrate to CV in the future, others probably never will. Emgu CV Emgu CV can be seen as two layers on top of OpenCV, which are explained as follows: Layer 1 is the basic layer. It includes enumeration, structure, and function mappings. The namespaces are direct wrappers from OpenCV components. Layer 2 is an upper layer. It takes good advantage of .NET framework and mixes the classes together. It can be seen in the bridge from OpenCV to .NET. The architecture of Emgu CV can be seen in the following diagram, which includes more details: After we create our new Emgu CV project, the first thing we will do is add references. Now we can see what those DLLs are used for: Emgu.Util.dll: A collection of .NET utilities Emgu.CV.dll: Basic image-processing algorithms from OpenCV Emgu.CV.UI.dll: Useful tools for Emgu controls Emgu.CV.GPU.dll: GPU processing (Nvidia Cuda) Emgu.CV.ML.dll: Machine learning algorithms

(For more resources related to this topic, see here.) Bonita connectors Bonita connectors are used to set variables or some other parameters inside Bonita. They can also be used to start a process or execute a step. These connectors equip the user to connect with different parameters of the Bonita work flow. The other kind of connectors are used to integrate with some other third-party tools. Most of the Bonita connectors are related to the documents and comments at a particular step. Although these may be useful in some cases, in a majority of the cases we will not find much use for them. The most useful ones are getting the users a step, executing a step, starting a new process, and setting variables. Click on any step on which you want to define the connector and click on Add.... Here, we will check the start an instance connector of Bonita. Give a name to this connector and click on Next. Here we have to fill in the name of the process that we want to invoke. We also have an option to specify different versions of the process. If we leave this blank, it will pick up the latest version. Next, we can specify the process variables that need to be copied from one pool to the other. Start an instance connector in Bonita Studio In the previous example, the process variables that we specify will be copied over to the target pool. We have to make sure that the target pool has the process variables mentioned in this connector. Make sure that you mention the name of the variable in the first column without the curly braces. If you select the names from the drop-down menu, make sure you remove the $ and the {} for filling in the name. The value field can be filled by the actual process variable. We can also use the set variable connector to set a value to a variable, either a process variable or a step variable. Here, we have two parameters: one is the variable whose value we have to set and the other parameter is the actual value of the variable. Note that this value may be a Groovy expression, too. Hence, it is similar to writing a Groovy script to assign a value to a variable. Another type of connector is the one to start or finish a step. In this connector, all we have to do is mention the name of the step we want to start or stop. Similarly, there is another connector to execute a step. Executing will run all the start and end Connectors of a particular step and then finish it. These connectors might be useful in the cases where some step may be waiting for another step, and at the end of the current step we might execute that step or mark it finished. We also have connectors to get the users from the workflow. There are connectors to find out the initiator of a process and the step submitter. Another useful connector is to get a user based on the username. This returns the User class that Bonita uses to implement the functionality of a user in the work flow. Select the connector to get a user from a username. Enter the username and click on Next. Here, we get the output of the connector and we can decide to save the output in a particular pool or step variable. Saving the connector output in a variable in Bonita The user class has methods to retrieve data, such as the e-mail, first name, last name, metadata, and password from the user. The e-mail connector We have a connector in the messaging group to send an e-mail. Now, we might use this connector for a variety of purposes: to send information about the work flow to an external e-mail, to send a notification to the person performing the task that he/she has some pending items in his/her inbox, and so on. We have to configure the e-mail connector on various parameters. In our TicketingWorkflow, let us send an e-mail to the person in whose name the tickets are booked. He/she enters his/her e-mail address in the Payment step of the workflow. Hence, let us send an e-mail at the end of the Payment step to the person at his/her e-mail address with which the tickets have been booked. For this, let us configure the e-mail connector: Click on the Payment step of the work flow. Click on the Connectors tab to add a connector. Select the connector as a medium to send an e-mail. Then name the connector as SendEmail and make sure that this connector is at the finish event of the step. In the next step, we are required to enter the configuration details of the SMTP server we will use for sending the e-mail. By default, it is set to the Gmail configuration with the host as smtp.gmail.com and the port as 465. Let us stick to the default option and send an e-mail from a Gmail hosted server. Leave the Security option as it is, but enter your credentials in the Authentication section. Here, you should enter your full e-mail address, not just your username. You can also use your own domain e-mail address if it is hosted on a Gmail server. Next, we define the parameters of the e-mail notification that has to be sent. After entering the From address as the ticketing admin address or some similar address, enter the To address as the variable in which we have saved the e-mail address: email. In the title field, we have to specify the subject of the e-mail. We have already seen that we can use Java inside the Groovy editor. Here, we will have a look at a simple Java code that is executed inside the editor. Enter the following code in the Groovy editor: import java.text.SimpleDateFormat; return "Flight ticket from " + from + " to " + to + " on " + new SimpleDateFormat("MM-dd-yyyy").format(departOn); The overview of the flight details is mentioned in the subject of the e-mail. We know that the departOn variable is a Date object. For printing the date, we have to convert it into a String by using the SimpleDateFormat class. Next, we have to write the actual e-mail that we will send to the customer. Below the Title field, make sure that the e-mail body is in HTML and not plain text. We can insert Groovy scripts in between the text, which will be substituted with the actual variable value when the e-mail is sent. Write the following in the body of the e-mail: Hi ${passenger1}, Your ${from} to ${to} flight is confirmed. The flight details are given below: Date Departure  Arrival Duration Price ${import java.text. SimpleDateFormat; return new SimpleDateFormat ("MM-dd-yyyy"). format(departOn); ${departure} ${arrival} ${duration} ${price} Travelers: ${passenger1} ${passenger2} ${passenger3} Payment Details: Card Holder - ${cardHolder} Card Number - ${cardNumber} Thank you for booking with TicketingWorkflow! Configuring the e-mail connector Clicking on Next will get you to the advanced options. Generally it's not really required to configure these options, and we can make do with the default settings. Summary This article looked at the various connector integration options available in Bonita Studio. It showed how connectors can be used to fetch data into the workflow and how to export data, too. We have a close look at the Bonita inbuilt connectors and e-mail connectors. Resources for Article: Further resources on this subject: Oracle BPM Suite 11gR1: Creating a BPM Application [Article] Managing Oracle Business Intelligence [Article] Setting Up Oracle Order Management [Article]

(For more resources related to this topic, see here.) Creating and migrating our to-do list's database As you know, migrations are very helpful to control development steps. We'll use migrations in this article. To create our first migration, type the following command: php artisan migrate:make create_todos_table --table=todos --create When you run this command, Artisan will generate a migration to generate a database table named todos. Now we should edit the migration file for the necessary database table columns. When you open the folder migration in app/database/ with a file manager, you will see the migration file under it. Let's open and edit the file as follows: <?php use IlluminateDatabaseMigrationsMigration; class CreateTodosTable extends Migration { /** * Run the migrations. * * @return void */ public function up() { Schema::create('todos', function(Blueprint $table){ $table->create(); $table->increments("id"); $table->string("title", 255); $table->enum('status', array('0', '1'))->default('0'); $table->timestamps(); }); } /** * Reverse the migrations. * * @return void */ public function down() { Schema::drop("todos"); } } To build a simple TO-DO list, we need five columns: The id column will store ID numbers of to-do tasks The title column will store a to-do task's title The status column will store statuses of the tasks The created_at and updated_at columns will store the created and updated dates of tasks If you write $table->timestamps() in the migration file, Laravel's migration class automatically creates created_at and updated_at columns. As you know, to apply migrations, we should run the following command: php artisan migrate After the command is run, if you check your database, you will see that our todos table and columns have been created. Now we need to write our model. Creating a todos model To create a model, you should open the app/models/ directory with your file manager. Create a file named Todo.php under the directory and write the following code: <?php class Todo extends Eloquent { protected $table = 'todos'; } Let's examine the Todo.php file. As you see, our Todo class extends an Eloquent model, which is the ORM (Object Relational Mapper) database class of Laravel. The protected $table = 'todos'; code tells Eloquent about our model's table name. If we don't set the table variable, Eloquent accepts the plural version of the lower case model name as table name. So this isn't required technically. Now, our application needs a template file, so let's create it. Creating the template Laravel uses a template engine that is called blade for static and application template files. Laravel calls the template files from the app/views/ directory, so we need to create our first template under this directory. Create a file with the name index.blade.php. The file contains the following code: <html> <head> <title>To-do List Application</title> <link rel="stylesheet" href="assets/css/style.css"> <!--[if lt IE 9]><script src = "//html5shim.googlecode.com/svn/trunk/html5.js"> </script><![endif]--> </head> <body> <div class="container"> <section id="data_section" class="todo"> <ul class="todo-controls"> <li><img src = "/assets/img/add.png" width="14px" onClick="show_form('add_task');" /></li> </ul> <ul id="task_list" class="todo-list"> @foreach($todos as $todo) @if($todo->status) <li id="{{$todo->id}}" class="done"> <a href="#" class="toggle"></a> <span id="span_{{$todo->id}}">{ {$todo->title}}</span> <a href="#" onClick="delete_task('{{$todo->id}}');" class="icon-delete">Delete</a> <a href="#" onClick="edit_task('{{$todo->id}}', '{{$todo->title}}');" class="icon-edit">Edit</a></li> @else <li id="{{$todo->id}}"><a href="#" onClick="task_done('{{$todo->id}}');" class="toggle"></a> <span id="span_{ {$todo->id}}">{{$todo->title}}</span> <a href="#" onClick="delete_task('{ {$todo->id}}');" class= "icon-delete">Delete</a> <a href="#" onClick="edit_task('{ {$todo->id}}','{{$todo->title}}');" class="icon-edit">Edit</a></li> @endif @endforeach </ul> </section> <section id="form_section"> <form id="add_task" class="todo" style="display:none"> <input id="task_title" type="text" name="title" placeholder="Enter a task name" value=""/> <button name="submit">Add Task</button> </form> <form id="edit_task" class="todo" style="display:none"> <input id="edit_task_id" type="hidden" value="" /> <input id="edit_task_title" type="text" name="title" value="" /> <button name="submit">Edit Task</button> </form> </section> </div> <script src = "http://code.jquery.com/ jquery-latest.min.js"type="text/javascript"></script> <script src = "assets/js/todo.js" type="text/javascript"></script> </body> </html> The preceding code may be difficult to understand if you're writing a blade template for the first time, so we'll try to examine it. You see a foreach loop in the file. This statement loops our todo records. We will provide you with more knowledge about it when we are creating our controller in this article. If and else statements are used for separating finished and waiting tasks. We use if and else statements for styling the tasks. We need one more template file for appending new records to the task list on the fly. Create a file with the name ajaxData.blade.php under app/views/ folder. The file contains the following code: @foreach($todos as $todo) <li id="{{$todo->id}}"><a href="#" onClick="task_done('{{$todo- >id}}');" class="toggle"></a> <span id="span_{{$todo >id}}">{{$todo->title}}</span> <a href="#" onClick="delete_task('{{$todo->id}}');" class="icon delete">Delete</a> <a href="#" onClick="edit_task('{{$todo >id}}','{{$todo->title}}');" class="icon-edit">Edit</a></li> @endforeach Also, you see the /assets/ directory in the source path of static files. When you look at the app/views directory, there is no directory named assets. Laravel separates the system and public files. Public accessible files stay under your public folder in root. So you should create a directory under your public folder for asset files. We recommend working with these types of organized folders for developing tidy and easy-to-read code. Finally you see that we are calling jQuery from its main website. We also recommend this way for getting the latest, stable jQuery in your application. You can style your application as you wish, hence we'll not examine styling code here. We are putting our style.css files under /public/assets/css/. For performing Ajax requests, we need JavaScript coding. This code posts our add_task and edit_task forms and updates them when our tasks are completed. Let's create a JavaScript file with the name todo.js in /public/assets/js/. The files contain the following code: function task_done(id){ $.get("/done/"+id, function(data) { if(data=="OK"){ $("#"+id).addClass("done"); } }); } function delete_task(id){ $.get("/delete/"+id, function(data) { if(data=="OK"){ var target = $("#"+id); target.hide('slow', function(){ target.remove(); }); } }); } function show_form(form_id){ $("form").hide(); $('#'+form_id).show("slow"); } function edit_task(id,title){ $("#edit_task_id").val(id); $("#edit_task_title").val(title); show_form('edit_task'); } $('#add_task').submit(function(event) { /* stop form from submitting normally */ event.preventDefault(); var title = $('#task_title').val(); if(title){ //ajax post the form $.post("/add", {title: title}).done(function(data) { $('#add_task').hide("slow"); $("#task_list").append(data); }); } else{ alert("Please give a title to task"); } }); $('#edit_task').submit(function() { /* stop form from submitting normally */ event.preventDefault(); var task_id = $('#edit_task_id').val(); var title = $('#edit_task_title').val(); var current_title = $("#span_"+task_id).text(); var new_title = current_title.replace(current_title, title); if(title){ //ajax post the form $.post("/update/"+task_id, {title: title}).done(function(data) { $('#edit_task').hide("slow"); $("#span_"+task_id).text(new_title); }); } else{ alert("Please give a title to task"); } }); Let's examine the JavaScript file.

(For more resources related to this topic, see here.) About Gideros Gideros is a set of software packages created and managed by a company named Gideros Mobile. It provides developers with the ability to create 2D games for multiple platforms by reusing the same code. Games created with Gideros run as native applications, thus having all the benefits of high performance and the utilization of the hardware power of a mobile device. Gideros uses Lua as its programming language, which is a lightweight scripting language with an easy learning curve and it is quite popular in the context of game development. A few of the greatest Gideros features are as follows: Its rapid prototyping and fast development time by providing a single-click on-device testing that enables you to compile and run your game from your computer to device in an instant A clean object-oriented approach that enables you to write clean and reusable code Additionally, Gideros is not limited to its provided API and can be extended to offer virtually any native platform features through its plugin system You can use all of these to create and even publish your game for free, if you don't mind a small Gideros splash screen being shown before your game starts Installing Gideros Currently, Gideros has no registration requirements for downloading its SDK, so you can easily navigate to their download page (http://giderosmobile.com/download) and download the version that is suitable for your operating system. As Gideros can be used on Linux only using the WINE emulator, it means that even for Linux you have to download the Windows version of Gideros. So, to sum it up: Download the Windows version for Windows and Linux OS Download the Mac version for OS X Gideros consists of multiple programs providing you with a basic package needed to develop your own mobile games. This software package includes the following features: Gideros Studio: It is a lightweight IDE to manage Gideros projects Gideros Player: It is a fast and lightweight desktop; iOS and Android players can run their apps with one click when testing Gideros Texture Packer: It is used to pack multiple textures in one texture for faster texture rendering Gideros Font Creator: It is used to create Bitmap fonts from different font formats for faster font rendering Gideros License Manager: It is used to license your downloaded copy of Gideros before exporting a project (required even for free accounts) An offline copy of the Gideros documentation and Reference API to get you started Creating your first project After you have downloaded and installed Gideros, you can try to create your first Gideros project. Although Gideros is IDE independent, and lot of other IDE's such as Lua Glider, Zero Brane, IntelliJ IDEA, and even Sublime can support Gideros, I would recommend that first-time users choose the provided Gideros Studio. That is what we will be using in this article. Trying out Gideros Studio You should note that I will be using the Windows version for screenshots and explanations, but Gideros Studio on other operating systems is quite similar, if not exactly the same. Therefore, it should not cause any confusion if you are using other versions of Gideros. When you open Gideros Studio, you will see a lot of different sections or what we will call panes. The largest pane will be the Start Page, which will provide you with the following options: Create New Project Access offline the Getting Started guide Access offline the Reference Manual Browse and try out Gideros Example Projects Go ahead and click on Create New Project, a New Project dialog will open. Now enter the name of your project, for example, New Project. Change the location of the project if you want to or leave it set to the default value, and click on OK when you are ready. Note that the Start Page is automatically closed and the space occupied by the Start Page is now free. This will be your coding pane, where all the code will be displayed. But first let's draw our attention to the Project pane, where you can see your chosen project name inside. In this pane, you will manage all the files used by your app. One important thing to note is that file/folder structure in Gideros Project pane is completely independent from your filesystem. This means that you will have to add files manually to the Gideros Studio Project pane. They won't show up automatically when you copy them into the project folder. And in your filesystem, files and folders may be organized completely different than those in Gideros Studio. This feature gives you the flexibility of managing multiple projects with the same code or asset base. When you, for example, want to include specific things in the iOS version of the game, which Android won't have, you can create two different projects in the same project directory, which could reuse the same files and simultaneously have their own independent, platform-specific files. So let's see how it actually works. Right-click on your project name inside the Project pane and select Add New File.... It will pop up the Add New File dialog. Like in many Lua development environments, an application should start with a main.lua file; so name your file main.lua and click on OK. You will now see that main.lua was added to your Project pane. And if you check the directory of your project in your filesystem, you will see that it also contains the main.lua file. Now double-click on main.lua inside the Project pane and it will open this file inside the code pane, where you can write a code for it. So let's try it out. Write a simple line of code: print("Hello world!") What this line will do is simply print out the provided string (Hello world!) inside the output console. Now save the project by either using the File menu or a diskette icon on the toolbar and let's run this project on a local desktop player. Using the Gideros desktop player To run our app, we first need to launch Gideros Player by clicking on a small joystick icon on the toolbar. This will open up the Gideros desktop player. The default screen of Gideros Player shows the current version of Gideros used and the IP address the player is bound to. Additionally, the desktop player provides different customizations: You can make it appear on the top of every window by navigating to View | Always on Top. You can change the zoom by navigating to View | Zoom. It is helpful when running the player in high resolutions, which might not fit the screen. You can select the orientation (portrait or landscape) of the player by navigating to Hardware | Orientation, to suit the needs of your app. You can provide the resolution you want to test your app in by navigating to Hardware | Resolution. It provides the most popular resolution templates to choose from. You can also set the frame rate of your app by navigating to Hardware | Frame Rate. Resolution selected in Gideros Player settings corresponds to the physical device you want to test your application on. All these options give you the flexibility to test your app across different device configurations from within one single desktop player. Now when the player is launched, you should see that the start and stop buttons of Gideros Studio are now enabled. And to run your project, all you need to do is click on the start button. You might need to launch Gideros Player and Gideros Studio with proper permissions and even add them to your Antivirus or Firewall's exceptions list to allow them to connect. The IP address and Gideros version of the player should disappear and you should only see a white screen there. That is because we did not actually display any graphical object as image. But what we did was printing some information to the console. So let's check the Output pane in the Gideros Studio. As you see the Output pane, there are some information messages, like the fact that main.lua was uploaded and the uploading process to the Gideros Player was finished successfully; but it also displays any text we pass to Lua print command, as in our case it was Hello world!. The Output pane is very handy for a simple debugging process by printing out the information using the print command. It also provides the error information if something is wrong with the project and it cannot be built. Now when we know what an Output pane is, let's actually display something on the player's screen. Summary In this article, you've learned a few features about Gideros Studio, such as installing Gideros on your machine, creating your first project, how to use the Gideros Player, and trying out your first project. Resources for Article: Further resources on this subject: Getting Started with PlayStation Mobile [Article] Getting Started with Marmalade [Article] Getting Started with GameSalad [Article]

(For more resources related to this topic, see here.) Case study Our project meets the following requirements: It depends on org.codehaus.jedi:jedi-XXX:3.0.5. Actually, the XXX is related to the JDK version, that is, either jdk5 or jdk6. The project is built and run on three different environments: PRODuction, UAT, and DEVelopment The underlying database differs owing to the environment: PostGre in PROD, MySQL in UAT, and HSQLDB in DEV. Besides, the connection is set in a Spring file, which can be spring-PROD.xml, spring-UAT.xml, or spring-DEV.xml, all being in the same src/main/resource folder. The first bullet point can be easily answered, using a jdk-version property. The dependency is then declared as follows: <dependency> <groupId>org.codehaus.jedi</groupId> <!--For this dependency two artifacts are available, one for jdk5 or and a second for jdk6--> <artifactId>jedi-${jdk.version}</artifactId> <version>${jedi.version}</version> </dependency> Still, the fourth bullet point is resolved by specifying a resource folder: <resources> <resource> <directory>src/main/resource</directory> <!--include the XML files corresponding to the environment: PROD, UAT, DEV. Here, the only XML file is a Spring configuration one. There is one file per environment--> <includes> <include> **/*-${environment}.xml </include> </includes> </resource> </resources> Then, we will have to run Maven adding the property values using one of the following commands: mvn clean install –Denvironment=PROD –Djdk.version=jdk6 mvn clean install –Denvironment=DEV –Djdk.version=jdk5 By the way, we could have merged the three XML files as a unique one, setting dynamically the content thanks to Maven's filter tag and mechanism. The next point to solve is the dependency to actual JDBC drivers. A quick and dirty solution A quick and dirty solution is to mention the three dependencies: <!--PROD --> <dependency> <groupId>postgresql</groupId> <artifactId>postgresql</artifactId> <version>9.1-901.jdbc4</version> <scope>runtime</scope> </dependency> <!--UAT--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.25</version> <scope>runtime</scope> </dependency> <!--DEV--> <dependency> <groupId>org.hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>2.3.0</version> <scope>runtime</scope> </dependency> Anyway, this idea has drawbacks. Even though only the actual driver (org. postgresql.Driver, com.mysql.jdbc.Driver, or org.hsqldb.jdbcDriver as described in the Spring files) will be instantiated at runtime, the three JARs will be transitively transmitted—and possibly packaged—in a further distribution. You may argue that we can work around this problem in most of situations, by confining the scope to provided, and embed the actual dependency by any other mean (such as rely on an artifact embarked in an application server); however, even then you should concede the dirtiness of the process. A clean solution Better solutions consist in using dynamic POM. Here, too, there will be a gradient of more or less clean solutions. Once more, as a disclaimer, beware of dynamic POMs! Dynamic POMs are a powerful and tricky feature of Maven. Moreover, modern IDEs manage dynamic POMs better than a few years ago. Yet, their use may be dangerous for newcomers: as with generated code and AOP for instance, what you write is not what you execute, which may result in strange or unexpected behaviors, needing long hours of debug and an aspirin tablet for the headache. This is why you have to carefully weigh their interest, relatively to your project before introducing them. With properties in command lines As a first step, let's define the dependency as follows: <!-- The dependency to effective JDBC drivers: PostGre, MySQL or HSQLDB--> <dependency> <groupId>${effective.groupId}</groupId> <artifactId> ${effective.artifactId} </artifactId> <version>${effective.version}</version> </dependency> As you can see, the dependency is parameterized thanks to three properties: effective.groupId, effective.artifactId, and effective.version. Then, in the same way we added earlier the –Djdk.version property, we will have to add those properties in the command line, for example,: mvn clean install –Denvironment=PROD –Djdk.version=jdk6 -Deffective.groupId=postgresql -Deffective.artifactId=postgresql -Deffective.version=9.1-901.jdbc4 Or add the following property mvn clean install –Denvironment=DEV –Djdk.version=jdk5 -Deffective.groupId=org.hsqldb -Deffective.artifactId=hsqldb -Deffective.version=2.3.0 Then, the effective POM will be reconstructed by Maven, and include the right dependencies: <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>3.2.3.RELEASE</version> <scope>compile</scope> </dependency> <dependency> <groupId>org.codehaus.jedi</groupId> <artifactId>jedi-jdk6</artifactId> <version>3.0.5</version> <scope>compile</scope> </dependency> <dependency> <groupId>postgresql</groupId> <artifactId>postgresql</artifactId> <version>9.1-901.jdbc4</version> <scope>compile</scope> </dependency> </dependencies> Yet, as you can imagine, writing long command lines like the preceding one increases the risks of human error, all the more that such lines are "write-only". These pitfalls are solved by profiles. Profiles and settings As an easy improvement, you can define profiles within the POM itself. The profiles gather the information you previously wrote in the command line, for example: <profile> <!-- The profile PROD gathers the properties related to the environment PROD--> <id>PROD</id> <properties> <environment>PROD</environment> <effective.groupId> postgresql </effective.groupId> <effective.artifactId> postgresql </effective.artifactId> <effective.version> 9.1-901.jdbc4 </effective.version> <jdk.version>jdk6</jdk.version> </properties> <activation> <!-- This profile is activated by default: in other terms, if no other profile in activated, then PROD will be--> <activeByDefault>true</activeByDefault> </activation> </profile> Or: <profile> <!-- The profile DEV gathers the properties related to the environment DEV--> <id>DEV</id> <properties> <environment>DEV</environment> <effective.groupId> org.hsqldb </effective.groupId> <effective.artifactId> hsqldb </effective.artifactId> <effective.version> 2.3.0 </effective.version> <jdk.version>jdk5</jdk.version> </properties> <activation> <!-- The profile DEV will be activated if, and only if, it is explicitly called--> <activeByDefault>false</activeByDefault> </activation> </profile> The corresponding command lines will be shorter: mvn clean install (Equivalent to mvn clean install –PPROD) Or: mvn clean install –PDEV You can list several profiles in the same POM, and one, many or all of them may be enabled or disabled. Nonetheless, multiplying profiles and properties hurts the readability. Moreover, if your team has 20 developers, then each developer will have to deal with 20 blocks of profiles, out of which 19 are completely irrelevant for him/her. So, in order to make the thing smoother, a best practice is to extract the profiles and inset them in the personal settings.xml files, with the same information: <?xml version="1.0" encoding="UTF-8"?> <settings xsi_schemaLocation="http://maven.apache.org/ SETTINGS/1.0.0 http://maven.apache.org/xsd/ settings-1.0.0.xsd"> <profiles> <profile> <id>PROD</id> <properties> <environment>PROD</environment> <effective.groupId> postgresql </effective.groupId> <effective.artifactId> postgresql </effective.artifactId> <effective.version> 9.1-901.jdbc4 </effective.version> <jdk.version>jdk6</jdk.version> </properties> <activation> <activeByDefault>true</activeByDefault> </activation> </profile> </profiles> </settings> Dynamic POMs – conclusion As a conclusion, the best practice concerning dynamic POMs is to parameterize the needed fields within the POM. Then, by order of priority: Set an enabled profile and corresponding properties within the settings.xml. mvn <goals> [-f <pom_Without_Profiles.xml> ] [-s <settings_With_Enabled_Profile.xml>] Otherwise, include profiles and properties within the POM mvn <goals> [-f <pom_With_Profiles.xml> ] [-P<actual_Profile> ] [-s <settings_Without_Profile.xml>] Otherwise, launch Maven with the properties in command lines mvn <goals> [-f <pom_Without_Profiles.xml> ] [-s <settings_Without_Profile.xml>] -D<property_1>=<value_1> -D<property_2>=<value_2> (...) -D<property_n>=<value_n> Summary In this article we learned about Dynamic POM. We saw a case study and also saw its quick and easy solutions. Resources for Article: Further resources on this subject: Integrating Scala, Groovy, and Flex Development with Apache Maven [Article] Creating a Camel project (Simple) [Article] Using Hive non-interactively (Simple) [Article]

(For more resources related to this topic, see here.) As you attempted to gather data, you might have realized that the information was trapped in a proprietary spreadsheet format or spread across pages on the Web. Making matters worse, after spending hours manually reformatting the data, perhaps your computer slowed to a crawl after running out of memory. Perhaps R even crashed or froze your machine. Hopefully you were undeterred; it does get easier with time. You might find the information particularly useful if you tend to work with data that are: Stored in unstructured or proprietary formats such as web pages, web APIs, or spreadsheets From a domain such as bioinformatics or social network analysis, which presents additional challenges So extremely large that R cannot store the dataset in memory or machine learning takes a very long time to complete You're not alone if you suffer from any of these problems. Although there is no panacea—these issues are the bane of the data scientist as well as the reason for data skills to be in high demand—through the dedicated efforts of the R community, a number of R packages provide a head start toward solving the problem. This article also provides a cookbook of such solutions. Even if you are an experienced R veteran, you may discover a package that simplifies your workflow, or perhaps one day you will author a package that makes work easier for everybody else! Working with specialized data Unlike the analyses in this article, real-world data are rarely packaged in a simple CSV form that can be downloaded from a website. Instead, significant effort is needed to prepare data for analysis. Data must be collected, merged, sorted, filtered, or reformatted to meet the requirements of the learning algorithm. This process is known informally as data munging. Munging has become even more important as the size of typical datasets has grown from megabytes to gigabytes and data are gathered from unrelated and messy sources, many of which are domain-specific. Several packages and resources for working with specialized or domain-specific data are listed as follows: Getting data from the Web with the RCurl package The RCurl package by Duncan Temple Lang provides an R interface to the curl (client for URLs) utility, a command-line tool for transferring data over networks. The curl utility is useful for web scraping, which refers to the practice of harvesting data from websites and transforming it into a structured form. Documentation for the RCurl package can be found on the Web at http://www.omegahat.org/RCurl/. After installing the RCurl package, downloading a page is as simple as typing: > library(RCurl) > webpage <- getURL("http://www.packtpub.com/") This will save the full text of the Packt Publishing's homepage (including all web markup) into the R character object named webpage. As shown in the following lines, this is not very useful as-is: > str(webpage) chr "<!DOCTYPE html>n<html >More information on the XML package, including simple examples to get you started quickly, can be found at the project's website: http://www.omegahat.org/RSXML/. Reading and writing JSON with the rjson package The rjson package by Alex Couture-Beil can be used to read and write files in the JavaScript Object Notation (JSON) format. JSON is a standard, plaintext format, most often used for data structures and objects on the Web. The format has become popular recently due to its utility in creating web applications, but despite the name, it is not limited to web browsers. For details about the JSON format, go to http://www.json.org/. The JSON format stores objects in plain text strings. After installing the rjson package, to convert from JSON to R: > library(rjson) > r_object <- fromJSON(json_string) To convert from an R object to a JSON object: >json_string <- toJSON(r_object) Used with the Rcurl package (noted previously), it is possible to write R programs that utilize JSON data directly from many online data stores. Reading and writing Microsoft Excel spreadsheets using xlsx The xlsx package by Adrian A. Dragulescu offers functions to read and write to spreadsheets in the Excel 2007 (or earlier) format—a common task in many business environments. The package is based on the Apache POI Java API for working with Microsoft's documents. For more information on xlsx, including a quick start document, go to https://code.google.com/p/rexcel/. Working with bioinformatics data Data analysis in the field of bioinformatics offers a number of challenges relative to other fields due to the unique nature of genetic data. The use of DNA and protein microarrays has resulted in datasets that are often much wider than they are long (that is, they have more features than examples). This creates problems when attempting to apply conventional visualizations, statistical tests, and machine learning-methods to such data. A CRAN task view for statistical genetics/bioinformatics is available at http://cran.r-project.org/web/views/Genetics.html. The Bioconductor project (http://www.bioconductor.org/) of the Fred Hutchinson Cancer Research Center in Seattle, Washington, provides a centralized hub for methods of analyzing genomic data. Using R as its foundation, Bioconductor adds packages and documentation specific to the field of bioinformatics. Bioconductor provides workflows for analyzing microarray data from common platforms such as for analysis of microarray platforms, including Affymetrix, Illumina, Nimblegen, and Agilent. Additional functionality includes sequence annotation, multiple testing procedures, specialized visualizations, and many other functions. Working with social network data and graph data Social network data and graph data present many challenges. These data record connections, or links, between people or objects. With N people, an N by N matrix of links is possible, which creates tremendous complexity as the number of people grows. The network is then analyzed using statistical measures and visualizations to search for meaningful patterns of relationships. The network package by Carter T. Butts, David Hunter, and Mark S. Handcock offers a specialized data structure for working with such networks. A closely-related package, sna, allows analysis and visualization of the network objects. For more information on network and sna, refer to the project website hosted by the University of Washington: http://www.statnet.org/. Improving the performance of R R has a reputation for being slow and memory inefficient, a reputation that is at least somewhat earned. These faults are largely unnoticed on a modern PC for datasets of many thousands of records, but datasets with a million records or more can push the limits of what is currently possible with consumer-grade hardware. The problem is worsened if the data have many features or if complex learning algorithms are being used. CRAN has a high performance computing task view that lists packages pushing the boundaries on what is possible in R: http://cran.r-project.org/web/views/HighPerformanceComputing.html. Packages that extend R past the capabilities of the base package are being developed rapidly. This work comes primarily on two fronts: some packages add the capability to manage extremely large datasets by making data operations faster or by allowing the size of data to exceed the amount of available system memory; others allow R to work faster, perhaps by spreading the work over additional computers or processors, by utilizing specialized computer hardware, or by providing machine learning optimized to Big Data problems. Some of these packages are listed as follows. Managing very large datasets Very large datasets can sometimes cause R to grind to a halt when the system runs out of memory to store the data. Even if the entire dataset can fit in memory, additional RAM is needed to read the data from disk, which necessitates a total memory size much larger than the dataset itself. Furthermore, very large datasets can take a long amount of time to process for no reason other than the sheer volume of records; even a quick operation can add up when performed many millions of times. Years ago, many would suggest performing data preparation of massive datasets outside R in another programming language, then using R to perform analyses on a smaller subset of data. However, this is no longer necessary, as several packages have been contributed to R to address these Big Data problems. Making data frames faster with data.table The data.table package by Dowle, Short, and Lianoglou provides an enhanced version of a data frame called a data table. The data.table objects are typically much faster than data frames for subsetting, joining, and grouping operations. Yet, because it is essentially an improved data frame, the resulting objects can still be used by any R function that accepts a data frame. The data.table project is found on the Web at http://datatable.r-forge.r-project.org/. One limitation of data.table structures is that like data frames, they are limited by the available system memory. The next two sections discuss packages that overcome this shortcoming at the expense of breaking compatibility with many R functions. Creating disk-based data frames with ff The ff package by Daniel Adler, Christian Glaser, Oleg Nenadic, Jens Oehlschlagel, and Walter Zucchini provides an alternative to a data frame (ffdf) that allows datasets of over two billion rows to be created, even if this far exceeds the available system memory. The ffdf structure has a physical component that stores the data on disk in a highly efficient form and a virtual component that acts like a typical R data frame but transparently points to the data stored in the physical component. You can imagine the ffdf object as a map that points to a location of data on a disk. The ff project is on the Web at http://ff.r-forge.r-project.org/. A downside of ffdf data structures is that they cannot be used natively by most R functions. Instead, the data must be processed in small chunks, and the results should be combined later on. The upside of chunking the data is that the task can be divided across several processors simultaneously using the parallel computing methods presented later in this article. The ffbase package by Edwin de Jonge, Jan Wijffels, and Jan van der Laan addresses this issue somewhat by adding capabilities for basic statistical analyses using ff objects. This makes it possible to use ff objects directly for data exploration. The ffbase project is hosted at http://github.com/edwindj/ffbase. Using massive matrices with bigmemory The bigmemory package by Michael J. Kane and John W. Emerson allows extremely large matrices that exceed the amount of available system memory. The matrices can be stored on disk or in shared memory, allowing them to be used by other processes on the same computer or across a network. This facilitates parallel computing methods, such as those covered later in this article. Additional documentation on the bigmemory package can be found at http://www.bigmemory.org/. Because bigmemory matrices are intentionally unlike data frames, they cannot be used directly with most of the machine learning methods covered in this book. They also can only be used with numeric data. That said, since they are similar to a typical R matrix, it is easy to create smaller samples or chunks that can be converted to standard R data structures. The authors also provide bigalgebra, biganalytics, and bigtabulate packages, which allow simple analyses to be performed on the matrices. Of particular note is the bigkmeans() function in the biganalytics package, which performs k-means clustering. Learning faster with parallel computing In the early days of computing, programs were entirely serial, which limited them to performing a single task at a time. The next instruction could not be performed until the previous instruction was complete. However, many tasks can be completed more efficiently by allowing work to be performed simultaneously. This need was addressed by the development of parallel computing methods, which use a set of two or more processors or computers to solve a larger problem. Many modern computers are designed for parallel computing. Even in the case that they have a single processor, they often have two or more cores which are capable of working in parallel. This allows tasks to be accomplished independently from one another. Networks of multiple computers called clusters can also be used for parallel computing. A large cluster may include a variety of hardware and be separated over large distances. In this case, the cluster is known as a grid. Taken to an extreme, a cluster or grid of hundreds or thousands of computers running commodity hardware could be a very powerful system. The catch, however, is that not every problem can be parallelized; certain problems are more conducive to parallel execution than others. You might expect that adding 100 processors would result in 100 times the work being accomplished in the same amount of time (that is, the execution time is 1/100), but this is typically not the case. The reason is that it takes effort to manage the workers; the work first must be divided into non-overlapping tasks and second, each of the workers' results must be combined into one final answer. So-called embarrassingly parallel problems are the ideal. These tasks are easy to reduce into non-overlapping blocks of work, and the results are easy to recombine. An example of an embarrassingly parallel machine learning task would be 10-fold cross-validation; once the samples are decided, each of the 10 evaluations is independent, meaning that its result does not affect the others. As you will soon see, this task can be sped up quite dramatically using parallel computing. Measuring execution time Efforts to speed up R will be wasted if it is not possible to systematically measure how much time was saved. Although you could sit and observe a clock, an easier solution is to wrap the offending code in a system.time() function. For example, on the author's laptop, the system.time() function notes that it takes about 0.13 seconds to generate a million random numbers: > system.time(rnorm(1000000)) user system elapsed 0.13 0.00 0.13 The same function can be used for evaluating improvement in performance, obtained with the methods that were just described or any R function. Working in parallel with foreach The foreach package by Steve Weston of Revolution Analytics provides perhaps the easiest way to get started with parallel computing, particularly if you are running R on the Windows operating system, as some of the other packages are platform-specific. The core of the package is a new foreach looping construct. If you have worked with other programming languages, this may be familiar. Essentially, it allows looping over a number of items in a set, without explicitly counting the number of items; in other words, for each item in the set, do something. In addition to the foreach package, Revolution Analytics has developed high-performance, enterprise-ready R builds. Free versions are available for trial and academic use. For more information, see their website at http://www.revolutionanalytics.com/. If you're thinking that R already provides a set of apply functions to loop over sets of items (for example, apply(), lapply(), sapply(), and so on), you are correct. However, the foreach loop has an additional benefit: iterations of the loop can be completed in parallel using a very simple syntax. The sister package doParallel provides a parallel backend for foreach that utilizes the parallel package included with R (Version 2.14.0 and later). The parallel package includes components of the multicore and snow packages described in the following sections. Using a multitasking operating system with multicore The multicore package by Simon Urbanek allows parallel processing on single machines that have multiple processors or processor cores. Because it utilizes multitasking capabilities of the operating system, it is not supported natively on Windows systems. An easy way to get started with the code package is using the mcapply() function, which is a parallelized version of lapply(). The multicore project is hosted at http://www.rforge.net/multicore/. Networking multiple workstations with snow and snowfall The snow package (simple networking of workstations) by Luke Tierney, A. J. Rossini, Na Li, and H. Sevcikova allows parallel computing on multicore or multiprocessor machines as well as on a network of multiple machines. The snowfall package by Jochen Knaus provides an easier-to-use interface for snow. For more information on code, including a detailed FAQ and information on how to configure parallel computing over a network, see http://www.imbi.uni-freiburg.de/parallel/. Parallel cloud computing with MapReduce and Hadoop The MapReduce programming model was developed at Google as a way to process their data on a large cluster of networked computers. MapReduce defined parallel programming as a two-step process: A map step, in which a problem is divided into smaller tasks that are distributed across the computers in the cluster A reduce step, in which the results of the small chunks of work are collected and synthesized into a final solution to the original problem A popular open source alternative to the proprietary MapReduce framework is Apache Hadoop. The Hadoop software comprises of the MapReduce concept plus a distributed filesystem capable of storing large amounts of data across a cluster of computers. Packt Publishing has published quite a number of books on Hadoop. To view the list of books on this topic, refer to Hadoop titles from Packt. Several R projects that provide an R interface to Hadoop are in development. One such project is RHIPE by Saptarshi Guha, which attempts to bring the divide and recombine philosophy into R by managing the communication between R and Hadoop. The RHIPE package is not yet available at CRAN, but it can be built from the source available on the Web at http://www.datadr.org. The RHadoop project by Revolution Analytics provides an R interface to Hadoop. The project provides a package, rmr, intended to be an easy way for R developers to write MapReduce programs. Additional RHadoop packages provide R functions for accessing Hadoop's distributed data stores. At the time of publication, development of RHadoop is progressing very rapidly. For more information about the project, see https://github.com/RevolutionAnalytics/RHadoop/wiki. GPU computing An alternative to parallel processing uses a computer's graphics processing unit (GPU) to increase the speed of mathematical calculations. A GPU is a specialized processor that is optimized for rapidly displaying images on a computer screen. Because a computer often needs to display complex 3D graphics (particularly for video games), many GPUs use hardware designed for parallel processing and extremely efficient matrix and vector calculations. A side benefit is that they can be used for efficiently solving certain types of mathematical problems. Where a computer processor may have on the order of 16 cores, a GPU may have thousands. The downside of GPU computing is that it requires specific hardware that is not included with many computers. In most cases, a GPU from the manufacturer Nvidia is required, as they provide a proprietary framework called CUDA (Complete Unified Device Architecture) that makes the GPU programmable using common languages such as C++. For more information on Nvidia's role in GPU computing, go to http://www.nvidia.com/object/what-is-gpu-computing.html. The gputools package by Josh Buckner, Mark Seligman, and Justin Wilson implements several R functions, such as matrix operations, clustering, and regression modeling using the Nvidia CUDA toolkit. The package requires a CUDA 1.3 or higher GPU and the installation of the Nvidia CUDA toolkit. Deploying optimized learning algorithms Some of the machine learning algorithms covered in this book are able to work on extremely large datasets with relatively minor modifications. For instance, it would be fairly straightforward to implement naive Bayes or the Apriori algorithm using one of the Big Data packages described previously. Some types of models such as ensembles, lend themselves well to parallelization, since the work of each model can be distributed across processors or computers in a cluster. On the other hand, some algorithms require larger changes to the data or algorithm, or need to be rethought altogether before they can be used with massive datasets. Building bigger regression models with biglm The biglm package by Thomas Lumley provides functions for training regression models on datasets that may be too large to fit into memory. It works by an iterative process in which the model is updated little-by-little using small chunks of data. The results will be nearly identical to what would have been obtained running the conventional lm() function on the entire dataset. The biglm() function allows use of a SQL database in place of a data frame. The model can also be trained with chunks obtained from data objects created by the ff package described previously. Growing bigger and faster random forests with bigrf The bigrf package by Aloysius Lim implements the training of random forests for classification and regression on datasets that are too large to fit into memory using bigmemory objects as described earlier in this article. The package also allows faster parallel processing using the foreach package described previously. Trees can be grown in parallel (on a single computer or across multiple computers), as can forests, and additional trees can be added to the forest at any time or merged with other forests. For more information, including examples and Windows installation instructions, see the package wiki hosted at GitHub: https://github.com/aloysius-lim/bigrf. Training and evaluating models in parallel with caret The caret package by Max Kuhn will transparently utilize a parallel backend if one has been registered with R (for instance, using the foreach package described previously). Many of the tasks involved in training and evaluating models, such as creating random samples and repeatedly testing predictions for 10-fold cross-validation are embarrassingly parallel. This makes a particularly good caret. Configuration instructions and a case study of the performance improvements for enabling parallel processing in caret are available at the project's website: http://caret.r-forge.r-project.org/parallel.html. Summary It is certainly an exciting time to be studying machine learning. Ongoing work on the relatively uncharted frontiers of parallel and distributed computing offers great potential for tapping the knowledge found in the deluge of Big Data. And the burgeoning data science community is facilitated by the free and open source R programming language, which provides a very low barrier for entry - you simply need to be willing to learn. The topics you have learned, provide the foundation for understanding more advanced machine learning methods. It is now your responsibility to keep learning and adding tools to your arsenal. Along the way, be sure to keep in mind the No Free Lunch theorem—no learning algorithm can rule them all. There will always be a human element to machine learning, adding subject-specific knowledge and the ability to match the appropriate algorithm to the task at hand. In the coming years, it will be interesting to see how the human side changes as the line between machine learning and human learning is blurred. Services such as Amazon's Mechanical Turk provide crowd-sourced intelligence, offering a cluster of human minds ready to perform simple tasks at a moment's notice. Perhaps one day, just as we have used computers to perform tasks that human beings cannot do easily, computers will employ human beings to do the reverse; food for thought. Resources for Article: Further resources on this subject: First steps with R [Article] SciPy for Computational Geometry [Article] Generating Reports in Notebooks in RStudio [Article]

(For more resources related to this topic, see here.) There are several editions of RSLogix 5000 available today, which are similar to Microsoft Windows' home and professional versions. The more "basic" (less expensive) editions of RSLogix 5000 have many features disabled. For example, only the full and professional editions, which are more expensive, support the editing of Function Block Diagrams, Graphical Structured Text, and Sequential Function Chart. In my experience, Ladder Logic is the most commonly used language. Refer to http://www.rockwellautomation.com/rockwellsoftware/design/rslogix5000/orderinginfo.html for more on this. Getting ready You will need to have added the cards and tags from the previous recipes to complete this exercise. How to do it... Open Controller Organizer and expand the leaf Tasks | Main Tasks | Main Program. Right-click on Main Program and select New Routine as shown in the following screenshot: Configure a new Ladder Logic program by setting the following values: Name: VALVES Description: Valve Control Program Type: Ladder Diagram For our newly created routine to be executed with each scan of the PLC, we will need to add a reference to it in MainRoutine that is executed with each scan of the MainTask task. Double-click on our MainRoutine program to display the Ladder Logic contained within it. Next, we will add a Jump To Subroutine (JSR) element that will add our newly added Ladder Diagram program to the main task and ensure that it is executed with each scan. Above the Ladder Diagram, there are tab buttons that organize Ladder Elements into Element Groups. Click on the left and right arrows that are on the left side of Element Groups and find the one labeled Program Control. After clicking on the Program Control element group, you will see the JSR element. Click on the JSR element to add it to the current Ladder Logic Rung in MainRoutine. Next, we will make some modifications to the JSR routine so that it calls our newly added Ladder Diagram. Click on the Routine Name parameter of the JSR element and select the VALVES routine from the list as shown in the following screenshot: There are three additional parameters that we are not using as part of the JSR element, which can be removed. Select the Input Par parameter and then click on the Remove Parameter icon in the toolbar above the Ladder Diagram. This icon looks as shown in the following screenshot: Repeat this process for the other optional parameter: Return Par. Now that we have ensured that our newly added Ladder Logic routine will be scanned, we can add the elements to our Ladder Logic routine. Double-click on our VALVES routine in the Controller Organizer tab under the MainTask task. Find the Timer/Counter element group and click on the TON (Timer On Delay) element to add it to our Ladder Diagram. Now we will create the Timer object. Enter the name in the Timer field as FC1001_TON. Right-click on the TIMER object tag name we just entered and select New "FC1001_TON" (or press Ctrl + W). In the New Tag form that appears, enter in the description FAULT TIMER FOR FLOW CONTROL VALVE 1001 and click on OK to create the new TIMER tag. Next, we will configure our TON element to count to five seconds (5,000 milliseconds). Double-click on the Preset parameter and enter in the value 5000, which is in milliseconds. Now, we will need to add the condition that will start the TIMER object. We will be adding a Less Than (LES) element from the Compare element group. Be sure to add the element to the same Ladder Logic Rung as the Timer on Delay element. The LES element will compare the valve position with the valve set point and return true if the values do not match. So set the two parameters of the LES element to the following: FC1001_PV FC1001_SP Now, we will add a second Ladder Logic Rung where a latched fault alarm is triggered after TIMER reaches five seconds. Right-click under the first Ladder Logic Rung and select Add Rung (or press Ctrl + R). Find the Favorites element group and select the Examine On icon as shown in the following screenshot: Click on ? above the Examine On tab and select the TIMER object's Done property, FC1001_TON.DN, as shown in the following screenshot. Now, once the valve values are not equal, and the TIMER has completed its count to five seconds, this Ladder Logic Rung will be activated as shown in the following screenshot: Next, we will add an Output Latched element to this Ladder Logic Rung. Click on the Output Latched element from the Favorites element group with our new rung selected. Click on ? above the Output Latched element and type in the name of a new base tag we are going to add as FC1001_FLT. Press Enter or click on the element to complete the text entry. Right-click on FC1001_FLT and select New "FC1001_FLT" (or press Ctrl + W). Set the following values in the New Tag form that appears: Description: FLOW CONTROL VALVE 1001 POSITION FAULT Type: Base Scope: FirstController Data Type: Bool Click on OK to add the new tag. Our new tag will look like the following screenshot: It is considered bad practice to latch a bit without having the code to unlatch the bit directly below it. Create a new BOOL type tag called ALARM_RESET with the following properties: Name: ALARM_RESET Description: RESET ALARMS Type: Base Scope: FirstController Data Type: BOOL Click on OK to add the new tag. Then add the following coil and OTU to unlatch the fault when the master alarm reset is triggered. Finally, we will add a comment so that we can see what our Ladder Diagram is doing at a glance. Right-click in the far-right area of the first Ladder Logic Rung (where the 0 is) and select Edit Rung Comment (Ctrl + D). Enter the following helpful comment: TRIGGER FAULT IF THE SETPOINT OF THE FLOW CONTROL VALVE 1001 IS NOT EQUAL TO THE VALVE POSITION How it works... We have created our first Ladder Logic Diagram and linked it to the MainTask task. Now, each time that the task is scanned (executed), our Ladder Logic routine will be run from left to right and top to bottom. There's more... More information on Ladder Logic can be found in the Rockwell publication Logix5000 Controllers Ladder Diagram available at http://literature.rockwellautomation.com/idc/groups/literature/documents/pm/1756-pm008_-en-p.pdf. Ladder Logic is the most commonly used programming language in RSLogix 5000. This recipe describes a few more helpful hints to get you started. Understanding Ladder Rung statuses Did you notice the vertical output eeeeeee on the left-hand side of your Ladder Logic Rung? This indicates that an error is present in your Ladder Logic code. After making changes to your controller project, it is a good practice to Verify your project using the drop-down menu item Logic | Verify | Controller. Once Verify has been run, you will see the error pane appear with any errors that it has detected. Element help You can easily get detailed documentation on Ladder Logic Elements, Function Block Diagram Elements, Structured Text Code, and other element types by selecting the object and pressing F1. Copying and pasting Ladder Logic Ladder Logic Rungs and elements can be copied and pasted within your ladder routine. Simply select the rung or element you wish to copy and press Ctrl + C. Then, to paste the rung or element, select the location where you would like to paste it and press Ctrl + V. Summary This article took a first look at creating new routines using ladder logic diagrams. The reader was introduced to the concept of Tasks and also learns how to link routines. In this article, we learned how to navigate the ladder elements that are available, how to find help on each element, and how to create a simple alarm timer using ladder logic. Resources for Article: Further resources on this subject: DirectX graphics diagnostic [Article] Flash 10 Multiplayer Game: Game Interface Design [Article] HTML5 Games Development: Using Local Storage to Store Game Data [Article]

(For more resources related to this topic, see here.) Getting started PyroCMS, like many other content management systems including WordPress, Typo3, or Drupal, comes with a pre-developed installation process. For PyroCMS, this installation process is easy to use and comes with a number of helpful hints just in case you hit a snag while installing the system. If, for example, your system files don't have the correct permissions profile (writeable versus write-protected), the PyroCMS installer will help you, along with all the other installation details, such as checking for required software and taking care of file permissions. Before you can install PyroCMS (the version used for examples in this article is 2.2) on a server, there are a number of server requirements that need to be met. If you aren't sure if these requirements have been met, the PyroCMS installer will check to make sure they are available before installation is complete. Following are the software requirements for a server before PyroCMS can be installed: HTTP Web Server MySQL 5.x or higher PHP 5.2.x or higher GD2 cURL Among these requirements, web developers interested in PyroCMS will be glad to know that it is built on CodeIgniter, a popular MVC patterned PHP framework. I recommend that the developers looking to use PyroCMS should also have working knowledge of CodeIgniter and the MVC programming pattern. Learn more about CodeIgniter and see their excellent system documentation online at http://ellislab.com/codeigniter. CodeIgniter If you haven't explored the Model-View-Controller (MVC) programming pattern, you'll want to brush up before you start developing for PyroCMS. The primary reason that CodeIgniter is a good framework for a CMS is that it is a well-documented framework that, when leveraged in the way PyroCMS has done, gives developers power over how long a project will take to build and the quality with which it is built. Add-on modules for PyroCMS, for example, follow the MVC method, a programming pattern that saves developers time and keeps their code dry and portable. Dry and portable programming are two different concepts. Dry is an acronym for "don't repeat yourself" code. Portable code is like "plug-and-play" code—write it once so that it can be shared with other projects and used quickly. HTTP web server Out of the PyroCMS software requirements, it is obvious, you can guess, that a good HTTP web server platform will be needed. Luckily, PyroCMS can run on a variety of web server platforms, including the following: Abyss Web Server Apache 2.x Nginx Uniform Server Zend Community Server If you are new to web hosting and haven't worked with web hosting software before, or this is your first time installing PyroCMS, I suggest that you use Apache as a HTTP web server. It will be the system for which you will find the most documentation and support online. If you'd prefer to avoid Apache, there is also good support for running PyroCMS on Nginx, another fairly-well documented web server platform. MySQL Version 5 is the latest major release of MySQL, and it has been in use for quite some time. It is the primary database choice for PyroCMS and is thoroughly supported. You don't need expert level experience with MySQL to run PyroCMS, but you'll need to be familiar with writing SQL queries and building relational databases if you plan to create add-ons for the system. You can learn more about MySQL at http://www.mysql.com. PHP Version 5.2 of PHP is no longer the officially supported release of PHP, which is, at the time of this article, Version 5.4. Version 5.2, which has been criticized as being a low server requirement for any CMS, is allowed with PyroCMS because it is the minimum version requirement for CodeIgniter, the framework upon which PyroCMS is built. While future versions of PyroCMS may upgrade this minimum requirement to PHP 5.3 or higher, you can safely use PyroCMS with PHP 5.2. Also, many server operating systems, like SUSE and Ubuntu, install PHP 5.2 by default. You can, of course, upgrade PHP to the latest version without causing harm to your instance of PyroCMS. To help future-proof your installation of PyroCMS, it may be wise to install PHP 5.3 or above, to maximize your readiness for when PyroCMS more strictly adopts features found in PHP 5.3 and 5.4, such as namespaceing. GD2 GD2, a library used in the manipulation and creation of images, is used by PyroCMS to dynamically generate images (where needed) and to crop and resize images used in many PyroCMS modules and add-ons. The image-based support offered by this library is invaluable. cURL As described on the cURL project website, cURL is "a command line tool for transferring data with URL syntax" using a large number of methods, including HTTP(S) GET, POST, PUT, and so on. You can learn more about the project and how to use cURL on their website http://curl.haxx.se. If you've never used cURL with PHP, I recommend taking time to learn how to use it, especially if you are thinking about building a web-based API using PyroCMS. Most popular web hosting companies meet the basic server requirements for PyroCMS. Downloading PyroCMS Getting your hands on a copy of PyroCMS is very simple. You can download the system files from one of two locations, the PryoCMS project website and GitHub. To download PyroCMS from the project website, visit http://www.pyrocms.com and click on the green button labeled Get PyroCMS! This will take you to a download page that gives you the choice between downloading the Community version of PyroCMS and buying the Professional version. If you are new to PyroCMS, you can start with the Community version, currently at Version 2.2.3. The following screenshot shows the download screen: To download PyroCMS from GitHub, visit https://github.com/pyrocms/pyrocms and click on the button labeled Download ZIP to get the latest Community version of PyroCMS, as shown in the following screenshot: If you know how to use Git, you can also clone a fresh version of PyroCMS using the following command. A word of warning, cloning PyroCMS from GitHub will usually give you the latest, stable release of the system, but it could include changes not described in this article. Make sure you checkout a stable release from PyroCMS's repository. git clone https://github.com/pyrocms/pyrocms.git As a side-note, if you've never used Git, I recommend taking some time to get started using it. PyroCMS is an open source project hosted in a Git repository on Github, which means that the system is open to being improved by any developer looking to contribute to the well-being of the project. It is also very common for PyroCMS developers to host their own add-on projects on Github and other online Git repository services. Summary In this article, we have covered the pre-requisites for using PyroCMS, and also how to download PyroCMS. Resources for Article : Further resources on this subject: Kentico CMS 5 Website Development: Managing Site Structure [Article] Kentico CMS 5 Website Development: Workflow Management [Article] Web CMS [Article]

Before Apache Karaf can provide you with an OSGi-based container runtime, we'll have to set up our environment first. The process is quick, requiring a minimum of normal Java usage integration work. In this article we'll review: The prerequisites for Apache Karaf Obtaining Apache Karaf Installing Apache Karaf and running it for the first time Prerequisites As a lightweight container, Apache Karaf has sparse system requirements. You will need to check that you have all of the below specifications met or exceeded: Operating System: Apache Karaf requires recent versions of Windows, AIX, Solaris, HP-UX, and various Linux distributions (RedHat, Suse, Ubuntu, and so on). Disk space: It requires at least 20 MB free disk space. You will require more free space as additional resources are provisioned into the container. As a rule of thumb, you should plan to allocate 100 to 1000 MB of disk space for logging, bundle cache, and repository. Memory: At least 128 MB memory is required; however, more than 2 GB is recommended. Java Runtime Environment (JRE): The runtime environments such as JRE 1.6 or JRE 1.7 are required. The location of the JRE should be made available via environment setting JAVA_HOME. At the time of writing, Java 1.6 is "end of life". For our demos we'll use Apache Maven 3.0.x and Java SDK 1.7.x; these tools should be obtained for future use. However, they will not be necessary to operate the base Karaf installation. Before attempting to build demos, please set the MAVEN_HOME environment variable to point towards your Apache Maven distribution. After verifying you have the above prerequisite hardware, operating system, JVM, and other software packages, you will have to set up your environment variables for JAVA_HOME and MAVEN_HOME. Both of these will be added to the system PATH. Setting up JAVA_HOME Environment Variable Apache Karaf honors the setting of JAVA_HOME in the system environment; if this is not set, it will pick up and use Java from PATH. For users unfamiliar with setting environment variables, the following batch setup script will set up your windows environment: @echo off REM execute setup.bat to setup environment variables. set JAVA_HOME=C:Program FilesJavajdk1.6.0_31 set MAVEN_HOME=c:x1apache-maven-3.0.4 set PATH=%JAVA_HOME%bin;%MAVEN_HOME%bin;%PATH%echo %PATH% The script creates and sets the JAVA_HOME and MAVEN_HOME variables to point to their local installation directories, and then adds their values to the system PATH. The initial echo off directive reduces console output as the script executes; the final echo command prints the value of PATH. Managing Windows System Environment Variables Windows environment settings can be managed via the Systems Properties control panel. Access to these controls varies according to the Windows release. Conversely, in a Unix-like environment, a script similar to the following one will set up your environment: # execute setup.sh to setup environment variables. JAVA_HOME=/path/to/jdk1.6.0_31 MAVEN_HOME=/path/to/apache-maven-3.0.4 PATH=$JAVA_HOME/bin:$MAVEN_HOME/bin:$PATH export PATH JAVA_HOME MAVEN_HOME echo $PATH The first two directives create and set the JAVA_HOME and MAVEN_HOME environment variables, respectively. These values are added to the PATH setting, and then made available to the environment via the export command. Obtaining Apache Karaf distribution As an Apache open source project, Apache Karaf is made available in both binary and source distributions. The binary distribution comes in a Linux-friendly, GNU-compressed archive and in Windows ZIP format. Your selection of distribution kit will affect which set of scripts are available in Karaf's bin folder. So, if you're using Windows, select the ZIP file; on Unix-like systems choose the tar.gz file. Apache Karaf distributions may be obtained from http://karaf.apache.org/index/community/download.html. The following screenshot shows this link: The primary download site for Apache Karaf provides a list of available mirror sites; it is advisable that you select a server nearer to your location for faster downloads. For the purposes of this article, we will be focusing on Apache Karaf 2.3.x with notes upon the 3.0.x release series. Apache Karaf 2.3.x versus 3.0.x series The major difference between Apache Karaf 2.3 and 3.0 lines is the core OSGi specification supported. Karaf 2.3 utilizes OSGi rev4.3, while Karaf 3.0 uses rev5.0. Karaf 3 also introduces several command name changes. There are a multitude of other internal differences between the code bases, and wherever appropriate, we'll highlight those changes that impact users throughout this text. Installing Apache Karaf The installation of Apache Karaf only requires you to extract the tar.gz or .zip file in your desired target folder destination. The following command is used in Windows: unzip apache-karaf-.zip The following command is used in Unix: tar –zxf apache-karaf-.tar.gz After extraction, the following folder structure will be present: The LICENSE, NOTICE, README, and RELEASE-NOTES files are plain text artifacts contained in each Karaf distribution. The RELEASE-NOTES files are of particular interest, as upon each major and minor release of Karaf, this file is updated with a list of changes. The LICENSE, NOTICE, README, and RELEASE-NOTES files are plain text artifacts contained in each Karaf distribution. The RELEASE-NOTES files are of particular interest, as upon each major and minor release of Karaf, this file is updated with a list of changes. The bin folder contains the Karaf scripts for the interactive shell (Karaf), starting and stopping background Karaf service, a client for connecting to running Karaf instances, and additional utilities. The data folder is home to Karaf's logfiles, bundle cache, and various other persistent data. The demos folder contains an assortment of sample projects for Karaf. It is advisable that new users explore these examples to gain familiarity with the system. For the purposes of this book we strived to create new sample projects to augment those existing in the distribution. The instances folder will be created when you use Karaf child instances. It stores the child instance folders and files. The deploy folder is monitored for hot deployment of artifacts into the running container. The etc folder contains the base configuration files of Karaf; it is also monitored for dynamic configuration updates to the configuration admin service in the running container. An HTML and PDF format copy of the Karaf manual is included in each kit. The lib folder contains the core libraries required for Karaf to boot upon a JVM. The system folder contains a simple repository of dependencies Karaf requires for operating at runtime. This repository has each library jar saved under a Maven-style directory structure, consisting of the library Maven group ID, artifact ID, version, artifact ID-version, any classifier, and extension. First boot! After extracting the Apache Karaf distribution kit and setting our environment variables, we are now ready to start up the container. The container can be started by invoking the Karaf script provided in the bin directory: On Windows, use the following command: binkaraf.bat On Unix, use the following command: ./bin/karaf The following image shows the first boot screen: Congratulations, you have successfully booted Apache Karaf! To stop the container, issue the following command in the console: karaf@root> shutdown –f The inclusion of the –for –-force flag to the shutdown command instructs Karaf to skip asking for confirmation of container shutdown. Pressing Ctrl+ D will shut down Karaf when you are on the shell; however, if you are connected remotely (using SSH), this action will just log off the SSH session, it won't shut down Karaf. Summary We have discovered the prerequisites for installing Karaf, which distribution to obtain, how to install the container, and finally how to start it. Resources for Article: Further resources on this subject: Apache Felix Gogo [Article] WordPress 3 Security: Apache Modules [Article] Configuring Apache and Nginx [Article]

(For more resources related to this topic, see here.) Getting ready The use of static methods is usually considered a bad Object Oriented Programming practice, but if we end up in a project that uses a pattern such as active record (see http://en.wikipedia.org/wiki/Active_record_pattern), we will end up having a lot of static methods. In such situations, we will need to write some unit tests and PowerMock could be quite handy. Start your favorite IDE (which we set up in the Getting and installing PowerMock (Simple) recipe), and let's fire away. How to do it... We will start where we left off. In the EmployeeService.java file, we need to implement the getEmployeeCount method; currently it throws an instance of UnsupportedOperationException. Let's implement the method in the EmployeeService class; the updated classes are as follows: /** * This class is responsible to handle the CRUD * operations on the Employee objects. * @author Deep Shah */ public class EmployeeService { /** * This method is responsible to return * the count of employees in the system. * It does it by calling the * static count method on the Employee class. * @return Total number of employees in the system. */ public int getEmployeeCount() { return Employee.count(); } } /** * This is a model class that will hold * properties specific to an employee in the system. * @author Deep Shah */ public class Employee { /** * The method that is responsible to return the * count of employees in the system. * @return The total number of employees in the system. * Currently this * method throws UnsupportedOperationException. */ public static int count() { throw new UnsupportedOperationException(); } } The getEmployeeCount method of EmployeeService calls the static method count of the Employee class. This method in turn throws an instance of UnsupportedOperationException. To write a unit test of the getEmployeeCount method of EmployeeService, we will need to mock the static method count of the Employee class. Let's create a file called EmployeeServiceTest.java in the test directory. This class is as follows: /** * The class that holds all unit tests for * the EmployeeService class. * @author Deep Shah */ @RunWith(PowerMockRunner.class) @PrepareForTest(Employee.class) public class EmployeeServiceTest { @Test public void shouldReturnTheCountOfEmployeesUsingTheDomainClass() { PowerMockito.mockStatic(Employee.class); PowerMockito.when(Employee.count()).thenReturn(900); EmployeeService employeeService = newEmployeeService(); Assert.assertEquals(900,employeeService.getEmployeeCount()); } } If we run the preceding test, it passes. The important things to notice are the two annotations (@RunWith and @PrepareForTest) at the top of the class, and the call to the PowerMockito.mockStatic method. The @RunWith(PowerMockRunner.class) statement tells JUnit to execute the test using PowerMockRunner. The @PrepareForTest(Employee.class) statement tells PowerMock to prepare the Employee class for tests. This annotation is required when we want to mock final classes or classes with final, private, static, or native methods. The PowerMockito.mockStatic(Employee.class) statement tells PowerMock that we want to mock all the static methods of the Employee class. The next statements in the code are pretty standard, and we have looked at them earlier in the Saying Hello World! (Simple) recipe. We are basically setting up the static count method of the Employee class to return 900. Finally, we are asserting that when the getEmployeeCount method on the instance of EmployeeService is invoked, we do get 900 back. Let's look at one more example of mocking a static method; but this time, let's mock a static method that returns void. We want to add another method to the EmployeeService class that will increment the salary of all employees (wouldn't we love to have such a method in reality?). Updated code is as follows: /** * This method is responsible to increment the salary * of all employees in the system by the given percentage. * It does this by calling the static giveIncrementOf method * on the Employee class. * @param percentage the percentage value by which * salaries would be increased * @return true if the increment was successful. * False if increment failed because of some exception* otherwise. */ public boolean giveIncrementToAllEmployeesOf(intpercentage) { try{ Employee.giveIncrementOf(percentage); return true; } catch(Exception e) { return false; } } The static method Employee.giveIncrementOf is as follows: /** * The method that is responsible to increment * salaries of all employees by the given percentage. * @param percentage the percentage value by which * salaries would be increased * Currently this method throws * UnsupportedOperationException. */ public static void giveIncrementOf(int percentage) { throw new UnsupportedOperationException(); } The earlier syntax would not work for mocking a void static method . The test case that mocks this method would look like the following: @RunWith(PowerMockRunner.class) @PrepareForTest(Employee.class) public class EmployeeServiceTest { @Test public void shouldReturnTrueWhenIncrementOf10PercentageIsGivenSuccessfully() { PowerMockito.mockStatic(Employee.class); PowerMockito.doNothing().when(Employee.class); Employee.giveIncrementOf(10); EmployeeService employeeService = newEmployeeService(); Assert.assertTrue(employeeService.giveIncrementToAllEmployeesOf(10)); } @Test public void shouldReturnFalseWhenIncrementOf10PercentageIsNotGivenSuccessfully() { PowerMockito.mockStatic(Employee.class); PowerMockito.doThrow(newIllegalStateException()).when(Employee.class); Employee.giveIncrementOf(10); EmployeeService employeeService = newEmployeeService(); Assert.assertFalse(employeeService.giveIncrementToAllEmployeesOf(10)); } } Notice that we still need the two annotations @RunWith and @PrepareForTest, and we still need to inform PowerMock that we want to mock the static methods of the Employee class. Notice the syntax for PowerMockito.doNothing and PowerMockito.doThrow: The PowerMockito.doNothing method tells PowerMock to literally do nothing when a certain method is called. The next statement of the doNothing call sets up the mock method. In this case it's the Employee.giveIncrementOf method. This essentially means that PowerMock will do nothing when the Employee.giveIncrementOf method is called. The PowerMockito.doThrow method tells PowerMock to throw an exception when a certain method is called. The next statement of the doThrow call tells PowerMock about the method that should throw an exception; in this case, it would again be Employee.giveIncrementOf. Hence, when the Employee.giveIncrementOf method is called, PowerMock will throw an instance of IllegalStateException. How it works... PowerMock uses custom class loader and bytecode manipulation to enable mocking of static methods. It does this by using the @RunWith and @PrepareForTest annotations. The rule of thumb is whenever we want to mock any method that returns a non-void value , we should be using the PowerMockito.when().thenReturn() syntax. It's the same syntax for instance methods as well as static methods. But for methods that return void, the preceding syntax cannot work. Hence, we have to use PowerMockito.doNothing and PowerMockito.doThrow. This syntax for static methods looks a bit like the record-playback style. On a mocked instance created using PowerMock, we can choose to return canned values only for a few methods; however, PowerMock will provide defaults values for all the other methods. This means that if we did not provide any canned value for a method that returns an int value, PowerMock will mock such a method and return 0 (since 0 is the default value for the int datatype) when invoked. There's more... The syntax of PowerMockito.doNothing and PowerMockito.doThrow can be used on instance methods as well. .doNothing and .doThrow on instance methods The syntax on instance methods is simpler compared to the one used for static methods. Let's say we want to mock the instance method save on the Employee class. The save method returns void, hence we have to use the doNothing and doThrow syntax. The test code to achieve is as follows: /** * The class that holds all unit tests for * the Employee class. * @author Deep Shah */ public class EmployeeTest { @Test() public void shouldNotDoAnythingIfEmployeeWasSaved() { Employee employee =PowerMockito.mock(Employee.class); PowerMockito.doNothing().when(employee.save(); try { employee.save(); } catch(Exception e) { Assert.fail("Should not have thrown anexception"); } } @Test(expected = IllegalStateException.class) public void shouldThrowAnExceptionIfEmployeeWasNotSaved() { Employee employee =PowerMockito.mock(Employee.class); PowerMockito.doThrow(newIllegalStateException()).when(employee).save(); employee.save(); } } To inform PowerMock about the method to mock, we just have to invoke it on the return value of the when method. The line PowerMockito.doNothing().when(employee).save() essentially means do nothing when the save method is invoked on the mocked Employee instance. Similarly, PowerMockito.doThrow(new IllegalStateException()).when(employee).save() means throw IllegalStateException when the save method is invoked on the mocked Employee instance. Notice that the syntax is more fluent when we want to mock void instance methods. Summary In this article, we saw how easily we can mock static methods. Resources for Article: Further resources on this subject: Important features of Mockito [Article] Python Testing: Mock Objects [Article] Easily Writing SQL Queries with Spring Python [Article]

(For more resources related to this topic, see here.) An introduction to Geolocation The term geolocation is used in order to refer to the identification process of the real-world geographic location of an object. Devices that are able to detect the user's position are becoming more common each day and we are now used to getting content based on our location ( geo targeting ). Using the Global Positioning System (GPS )—a space-based satellite navigation system that provides location and time information consistently across the globe—you can now get the accurate location of a device. During the early 1970s, the US military created Navstar, a defense navigation satellite system. Navstar was the system that created the basis for the GPS infrastructure used today by billions of devices. Since 1978 more than 60 GPS satellites have been successfully placed in the orbit around the Earth (refer to http://en.wikipedia.org/wiki/List_of_GPS_satellite_launches for a detailed report about the past and planned launches). The location of a device is represented through a point. This point is comprised of two components: latitude and longitude. There are many methods for modern devices to determine the location information, these include: Global Positioning System (GPS) IP address GSM/CDMA cell IDs Wi-Fi and Bluetooth MAC address Each approach delivers the same information; what changes is the accuracy of the device's position. The GPS satellites continuously transmit information that can parse, for example, the general health of the GPS array, roughly, where all of the satellites are in orbit, information on the precise orbit or path of the transmitting satellite, and the time of the transmission. The receiver calculates its own position by timing the signals sent by any of the satellites in the array that are visible. The process of measuring the distance from a point to a group of satellites to locate a position is known as trilateration . The distance is determined using the speed of light as a constant along with the time that the signal left the satellites. The emerging trend in mobile development is GPS-based "people discovery" apps such as Highlight, Sonar, Banjo, and Foursquare. Each app has different features and has been built for different purposes, but all of them share the same killer feature: using location as a piece of metadata in order to filter information according to the user's needs. The PhoneGap Geolocation API The Geolocation API is not a part of the HTML5 specification but it is tightly integrated with mobile development. The PhoneGap Geolocation API and the W3C Geolocation API mirror each other; both define the same methods and relative arguments. There are several devices that already implement the W3C Geolocation API; for those devices you can use native support instead of the PhoneGap API. As per the HTML specification, the user has to explicitly allow the website or the app to use the device's current position. The Geolocation API is exposed through the geolocation object child of the navigator object and consists of the following three methods: getCurrentPosition() returns the device position. watchPosition() watches for changes in the device position. clearWatch() stops the watcher for the device's position changes. The watchPosition() and clearWatch() methods work in the same way that the setInterval() and clearInterval() methods work; in fact the first one returns an identifier that is passed in to the second one. The getCurrentPosition() and watchPosition() methods mirror each other and take the same arguments: a success and a failure callback function and an optional configuration object. The configuration object is used in order to specify the maximum age of a cached value of the device's position, to set a timeout after which the method will fail and to specify whether the application requires only accurate results. var options = {maximumAge: 3000, timeout: 5000, enableHighAccuracy: true }; navigator.geolocation.watchPosition(onSuccess, onFailure, options); Only the first argument is mandatory; but it's recommended to handle always the failure use case. The success handler function receives as argument, a Position object. Accessing its properties you can read the device's coordinates and the creation timestamp of the object that stores the coordinates. function onSuccess(position) { console.log('Coordinates: ' + position.coords); console.log('Timestamp: ' + position.timestamp); } The coords property of the Position object contains a Coordinates object; so far the most important properties of this object are longitude and latitude. Using those properties it's possible to start to integrate positioning information as relevant metadata in your app. The failure handler receives as argument, a PositionError object. Using the code and the message property of this object you can gracefully handle every possible error. function onError(error) { console.log('message: ' + error.message); console.log ('code: ' + error.code); } The message property returns a detailed description of the error, the code property returns an integer; the possible values are represented through the following pseudo constants: PositionError.PERMISSION_DENIED, the user denies the app to use the device's current position PositionError.POSITION_UNAVAILABLE, the position of the device cannot be determined If you want to recover the last available position when the POSITION_UNAVAILABLE error is returned, you have to write a custom plugin that uses the platform-specific API. Android and iOS have this feature. You can find a detailed example at http://stackoverflow.com/questions/10897081/retrieving-last-known-geolocation-phonegap. PositionError.TIMEOUT, the specified timeout has elapsed before the implementation could successfully acquire a new Position object JavaScript doesn't support constants such as Java and other object-oriented programming languages. With the term "pseudo constants", I refer to those values that should never change in a JavaScript app. One of the most common tasks to perform with the device position information is to show the device location on a map. You can quickly perform this task by integrating Google Maps in your app; the only requirement is a valid API key. To get the key, use the following steps: Visit the APIs console at https://code.google.com/apis/console and log in with your Google account. Click the Services link on the left-hand menu. Activate the Google Maps API v3 service. Time for action – showing device position with Google Maps Get ready to add a map renderer to the PhoneGap default app template. Refer to the following steps: Open the command-line tool and create a new PhoneGap project named MapSample. $ cordova create ~/the/path/to/your/source/ mapmample com.gnstudio.pg.MapSample MapSample Add the Geolocation API plugin using the command line. $ cordova plugins add https: //git-wip-us.apache.org /repos/asf/cordova-plugin-geolocation.git Go to the www folder, open the index.html file, and add a div element with the id value #map inside the main div of the app below the #deviceready one. <div id='map'></div> Add a new script tag to include the Google Maps JavaScript library. <script type="text/javascript" src ="https: //maps.googleapis.com/maps/api/js?key= YOUR_API_KEY &sensor=true"> </script> Go to the css folder and define a new rule inside the index.css file to give to the div element and its content an appropriate size. #map{ width: 280px; height: 230px; display: block; margin: 5px auto; position: relative; } Go to the js folder, open the index.js file, and define a new function named initMap. initMap: function(lat, long){ // The code needed to show the map and the // device position will be added here } In the body of the function, define an options object in order to specify how the map has to be rendered. var options = { zoom: 8, center: new google.maps.LatLng(lat, long), mapTypeId: google.maps.MapTypeId.ROADMAP }; Add to the body of the initMap function the code to initialize the rendering of the map, and to show a marker representing the current device's position over it. var map = new google.maps.Map(document.getElementById('map'), options); var markerPoint = new google.maps.LatLng(lat, long); var marker = new google.maps.Marker({ position: markerPoint, map: map, title: 'Device's Location' }); Define a function to use as the success handler and call from its body the initMap function previously defined. onSuccess: function(position){ var coords = position.coords; app.initMap(coords.latitude, coords.longitude); } Define another function in order to have a failure handler able to notify the user that something went wrong. onFailure: function(error){ navigator.notification.alert(error.message, null); } Go into the deviceready function and add as the last statement the call to the Geolocation API needed to recover the device's position. navigator.geolocation.getCurrentPosition(app.onSuccess, app.onError, {timeout: 5000, enableAccuracy: false}); Open the command-line tool, build the app, and then run it on your testing devices. $ cordova build $ cordova run android What just happened? You integrated Google Maps inside an app. The map is an interactive map most users are familiar with—the most common gestures are already working and the Google Street View controls are already enabled. To successfully load the Google Maps API on iOS, it's mandatory to whitelist the googleapis.com and gstatic.com domains. Open the .plist file of the project as source code (right-click on the file and then Open As | Source Code ) and add the following array of domains: <key>ExternalHosts</key> <array> <string>*.googleapis.com</string> <string>*.gstatic.com</string> </array> Other Geolocation data In the previous example, you only used the latitude and longitude properties of the position object that you received. There are other attributes that can be accessed as properties of the Coordinates object: altitude, the height of the device, in meters, above the sea level. accuracy, the accuracy level of the latitude and longitude, in meters; it can be used to show a radius of accuracy when mapping the device's position. altitudeAccuracy, the accuracy of the altitude in meters. heading, the direction of the device in degrees clockwise from true north. speed, the current ground speed of the device in meters per second. Latitude and longitude are the best supported of these properties, and the ones that will be most useful when communicating with remote APIs. The other properties are mainly useful if you're developing an application for which Geolocation is a core component of its standard functionality, such as apps that make use of this data to create a flow of information contextualized to the geolocation data. The accuracy property is the most important of these additional features, because as an application developer, you typically won't know which particular sensor is giving you the location and you can use the accuracy property as a range in your queries to external services. There are several APIs that allow you to discover interesting data related to a place; among these the most interesting are the Google Places API and the Foursquare API. The Google Places and Foursquare online documentation is very well organized and it's the right place to start if you want to dig deeper into these topics. You can access the Google Places docs at https://developers.google.com/maps/documentation/javascript/places and Foursquare at https://developer.foursquare.com/. The itinero reference app for this article implements both the APIs. In the next example, you will look at how to integrate Google Places inside the RequireJS app. In order to include the Google Places API inside an app, all you have to do is add the libraries parameter to the Google Maps API call. The resulting URL should look similar to http://maps.google.com/maps/api/js?key=SECRET_KEY&sensor=true&libraries=places. The itinero app lets users create and plan a trip with friends. Once the user provides the name of the trip, the name of the country to be visited, and the trip mates and dates, it's time to start selecting the travel, eat, and sleep options. When the user selects the Eat option, the Google Places data provider will return bakeries, take-out places, groceries, and so on, close to the trip's destination. The app will show on the screen a list of possible places the user can select to plan the trip. For a complete list of the types of place searches supported by the Google API, refer to the online documentation at https://developers.google.com/places/documentation/supported_types.

(For more resources related to this topic, see here.) This article explains how to create and embed 2D and 3D charts. They can also be interactive or static and we will insert them into our Moodle courses. We will mainly work with several spreadsheets in order to include diverse tools and techniques that are also present. The main idea is to display data in charts and provide students with the necessary information for their activities. We will also work with a variety of charts and deal with statistics as a baseline topic in this article. We can either develop a chart or work with ready-to-use data. You can design these types of activities in your Moodle course, together with a math teacher. When thinking of statistics, we generally have in mind a picture of a chart and some percentages representing the data of the chart. We can change that paradigm and create a different way to draw and read statistics in our Moodle course. We design charts with drawings, map charts, links to websites, and other interesting items. We can also redesign the charts, comprising numbers, with different assets because we want not only to enrich, but also strengthen the diversity of the material for our Moodle course since some students are not keen on numbers and dislike activities with them. So, let's give another chance to statistics! There are different types of graphics to show statistics. Therefore, we show a variety of tools available to display different results. No matter what our subject is, we can include these types of graphics in our Moodle course. You can use these graphics to help your students give weight to their arguments and express themselves using key points clearly. We teach students to include graphics, read them, and use them as a tool of communication. We can also work with puzzles related to statistics. That is to say, we can invent a graph and give tips or clues to our students so that they can sort out which percentages belong to the chart. In other words, we can create a listening comprehension activity, a reading comprehension activity, or a math problem. We can just upload or embed the chart, create an appealing activity, and give clues to our students so that they can think of the items belonging to the chart. Inserting column charts In this activity, we work with the website http://populationaction.org/. We work with statistics about different topics that are related to each other. We can explore different countries and use several charts in order to draw conclusions. We can also embed the charts in our Moodle course. Getting ready We need to think of a country to work with. We can compare statistics of population, water, croplands, and forests of different countries in order to draw conclusions about their futures. How to do it... We go to the website mentioned earlier and follow some steps in order to get the HTML code to embed it in our Moodle course. In this case, we choose Canada. These are the steps to follow: Enter http://populationaction.org/ in the browser window. Navigate to Publications | Data & Maps. Click on People in the Balance. Click on the down arrow next to the Country or Region Name search block and choose Canada, as shown in the following screenshot: Go to the bottom of the page and click on Share. Copy the HTML code, as shown in the following screenshot: Click on Done. How it works... It is time to embed the charts in our Moodle course. Another option is to draw the charts using a spreadsheet. So, we choose the weekly outline section where we want to add this activity and perform the following steps: Click on Add an activity or resource. Click on Forum | Add. Complete the Forum name block. Click on the down arrow in Forum type and choose Q and A forum. Complete the Description block. Click on the Edit HTML source icon. Paste the HTML code that was copied. Click on Update. Click on the down arrow next to Subscription mode and choose Forced subscription. Click on Save and display. The activity looks as shown in the following screenshot: Embedding a line chart In this recipe, we will present the estimated number of people (in millions) using a particular language over the Internet. To do this, we may include images in our spreadsheet in accordance with the method being used to design the activity. Instead of writing the name of the languages, we insert the flags that represent the language used. We design the line chart taking into account the statistical operations carried out at http://www.internetworldstats.com/stats7.htm. Getting ready We carry out the activity using Google Docs. We have to sign in and follow the steps required to design a spreadsheet file. We have several options for working with the document. After you have an account to work with Google Drive, let's see how to make our line chart! How to do it... We work with s spreadsheet because we need to make calculations and create a chart. First, we need to create a document in the spreadsheet. Therefore, we need to perform the following steps: Click on Create | Spreadsheet, as shown in the following screenshot: Write the name of the languages spoken in the A column. Write the figures in the B column (from the http://www.internetworldstats.com/stats7.htm website). Select the data from A1 up to the B11 column. Click on Insert | Chart. Edit your chart using the Chart Editor, as shown in the following screenshot: Click on Insert. Add the images of the flags corresponding to the languages spoken. Position the cursor over C1 and click on Insert | Image.... Another pop-up window will appear. You have several ways to upload images, as shown in the following screenshot: Click on Choose an image to upload and insert the image from your computer. Click on Select. Repeat the same process for all the languages. Steps 7 to 11 are optional. Click on the chart. Click on the down arrow in Share | Publish chart..., as shown in the following screenshot: Click on the down arrow next to Select a public format and choose Image, as shown in the following screenshot: Copy the HTML code that appears, as shown in the previous screenshot. Click on Done. How it works... We have just designed the chart that we want our students to work with. We are going to embed the chart in our Moodle course; another option is to share the spreadsheet and allow students to draw the chart. If you want to design a warm-up activity for students to guess or find out which the top languages used over the Internet are, you could add a chat, forum, or a question in the course. In this recipe, we are going to create a wiki so that students can work together. So, select the weekly outline section where you want to add the activity and perform the following steps: Click on Add an activity or resource. Click on Wiki | Add. Complete the Wiki name and Description blocks. Click on the Edit HTML source icon and paste the HTML code that we have previously copied. Then click on Update. Complete the First page name block. Click on Save and return to course. The activity looks as shown in the following screenshot:

(For more resources related to this topic, see here.) So what is Haskell? It is a fast, type-safe, purely functional programming language with a powerful type inference. Having said that, let us try to understand what it gives us. First, a purely functional programming language means that, in general, functions in Haskell don't have side effects. There is a special type for impure functions, or functions with side effects. Then, Haskell has a strong, static type system with an automatic and robust type inference. This, in practice, means that you do not usually need to specify types of functions and also the type checker does not allow passing incompatible types. In strongly typed languages, types are considered to be a specification, due to the Curry-Howard correspondence, the direct relationship between programs and mathematical proofs. Under this great simplification, the theorem states that if a value of the type exists (or is inhabited), then the corresponding mathematical proof is correct. Or jokingly saying, if a program compiles, then there is 99 percent probability that it works according to specification. Though the question if the types conform, the specification in natural language is still open; Haskell won't help you with it. The Haskell platform The glorious Glasgow Haskell Compilation System, or simply Glasgow Haskell Compiler (GHC), is the most widely used Haskell compiler. It is the current de facto standard. The compiler is packaged into the Haskell platform that follows Python's principle, "Batteries included". The platform is updated twice a year with new compilers and libraries. It usually includes a compiler, an interactive Read-Evaluate-Print Loop (REPL) interpreter, Haskell 98/2010 libraries (so-called Prelude) that includes most of the common definitions and functions, and a set of commonly used libraries. If you are on Windows or Mac OS X, it is strongly recommended to use prepackaged installers of the Haskell platform at http://www.haskell.org/platform/. Quick tour of Haskell To start with development, first we should be familiar with a few basic features of Haskell. We really need to know about laziness, datatypes, pattern matching, type classes, and basic notion of monads to start with Haskell. Laziness Haskell is a language with lazy evaluation. From a programmer's point of view that means that the value is evaluated if and only if it is really needed. Imperative languages usually have a strict evaluation, that is, function arguments are evaluated before function application. To see the difference, let's take a look at a simple expression in Haskell: let x = 2 + 3 In a strict or eager language, the 2 + 3 expression would be immediately evaluated to 5, whereas in Haskell, only a promise to do this evaluation will be created and the value will be evaluated only when it is needed. In other words, this statement just introduces definition of x which might be used afterwards, unlike in strict language where it is an operator that assigns the computed value, 5 to a memory cell named x. Also, this strategy allows sharing of evaluations, because laziness assumes that computations can be executed whenever it is needed and therefore, the result can be memorized. It might reduce the running time by exponential factor over strict evaluation. Laziness also allows to manipulate with infinite data structures. For instance, we can construct an infinite list of natural numbers as follows: let ns = [1..] And moreover, we can manipulate it as if it is a normal list, even though some caution is needed, as you can get an infinite loop. We can take the first five elements of this infinite list by means of the built-in function, take: take 5 ns By running this example in GHCi you will get [1,2,3,4,5]. Functions as first-class citizens The notion of function is one of the core ideas in functional languages and Haskell is not an exception at all. The definition of a function includes a body of function and an optional type declaration. For instance, the take function is defined in Prelude as follows: take :: Int -> [a] -> [a] take = ... Here, the type declaration says that the function takes an integer as the argument and a list of objects of the a type, and returns a new list of the same type. Also Haskell allows partial application of a function. For example, you can construct a function that takes first five elements of the list as follows: take5 :: [a] -> [a] take5 = take 5 Also functions are themselves objects, that is, you may pass a function as an argument to another function. Prelude defines map function as a function of a function: map :: (a -> b) -> [a] -> [b] map takes a function and applies it to each element of the list. Thus functions are first-class citizens in the language and it is possible to manipulate with them as if they were normal objects. Data types Data type is a core of a strongly typed language as Haskell. The distinctive feature of Haskell data types is that they all are immutable, i.e. after object constructed it cannot be changed. It might be weird on the first sight but in the long run it has few positive consequences. First, it enables computation parallelization. Second, all data are referentially transparent, i.e. there is no difference between reference to object and object itself. Those two properties allow compiler to reason about code optimization on higher level than C/C++ compiler can. Let us consider the following data type definitions in Haskell: type TimeStamp = Integer newtype Price = Price Double data Quote = AskQuote TimeStamp Price | BidQuote TimeStamp Price There are three common ways to define data types in Haskell: The first declaration just creates a synonym for an existing data type and type checker won’t prevent you from using Integer instead of TimeStamp. Also you can use a value of type TimeStamp with any function that expects to work with an Integer. The second declaration creates a new type for prices and you are not allowed to use Double instead of Price. The compiler will raise an error in such cases and thus it will enforce the correct usage. The last declaration introduces Algebraic Data Type (ADT) and says that type Quote might be constructed either by data constructor AskQuote, or by BidQuote with time stamp and price as its parameters. Quote itself is called a type constructor. Type constructor might be parameterized by type variables. For example, types Maybe and Either, quite often used standard types, are defined as follows: data Maybe a = Nothing | Just a data Either a b = Left a | Right b Type variables a and b can be substituted by any other type. Type classes Type classes in Haskell are not classes like in object-oriented languages. It is more like interfaces with optional implementation. You can find them in other languages named traits, mix-ins and so on but unlike in them, this feature in Haskell enables ad-hoc polymorphism, i.e. function could be applied to arguments of different types. It is also known as function overloading or operator overloading. A polymorphic function can specify different implementation for different types. In principle, type class consists of function declaration over some objects. Eq type class is a standard type class that specifies how to compare two objects of same type: class Eq a where (==) :: a -> a -> Bool (/=) :: a -> a -> Bool (/=) x y = not $ (==) x y Here Eq is the name of type class, a is a type variable and == and /= are the operations defined in the type class. This definition means that some type a is of class Eq if it has defined operation == and /=. Moreover, the definition provides default implementation of the operation /=. And if you decide to implement this class for some data type, you need provide the single operation implementation. There are numbers of useful type classes defined in Prelude. For example, Eq is used to define equality between 2 objects; Ord specifies total ordering; Show and Read introduce a String representation of object; Enum type class describes enumerations, i.e. data types with null constructors. It might be quite boring to implement this quite trivial but useful type classes for each data type, so Haskell supports automatic derivation of most of standard type classes: newtype Price = Price Double deriving (Eq, Show, Read, Ord) Now objects of type Price could be converted from/to String by means of read/show functions and compared with themselves using equality operators. Those who want to know all the details can look them up in Haskell language report. IO monad Being a pure functional language Haskell requires a marker of impure functions and IO monad is the marker. Function Main is an entry point for any Haskell program. It cannot be a pure function because it changes state of the “World”, at least by creating a new process in OS. Let us take a look at its type: main :: IO () main = do putStrLn "Hello, World!" IO () type signs that there is a computation that performs some I/O operation and return empty result. There is really only one way to perform I/O in Haskell: use it in main procedure of your program. Also it is not possible to execute I/O action from arbitrary function, unless that function is in the IO monad and called from main, directly or indirectly. Summary In this article we walked through the main unique features of Haskell language and learned a bit of its history. Resources for Article : Further resources on this subject: Core Data iOS: Designing a Data Model and Building Data Objects [Article] The OpenFlow Controllers [Article] Managing Network Layout [Article]

(For more resources related to this topic, see here.) In APEX 4.0, Oracle introduced the plug-in feature. A plug-in is an extension to the existing functionality of APEX. The idea behind plug-ins is to make life easier for developers. Plug-ins are reusable, and can be exported and imported. In this way it is possible to create a functionality which is available to all APEX developers. And installing and using them without the need of having a knowledge of what's inside the plug-in. APEX translates settings from the APEX builder to HTML and JavaScript. For example, if you created a text item in the APEX builder, APEX converts this to the following code (simplified): <input type="text" id="P12_NAME" name="P12_NAME" value="your name"> When you create an item type plug-in, you actually take over this conversion task of APEX, and you generate the HTML and JavaScript code yourself by using PL/SQL procedures. That offers a lot of flexibility because now you can make this code generic, so that it can be used for more items. The same goes for region type plug-ins. A region is a container for forms, reports, and so on. The region can be a div or an HTML table. By creating a region type plug-in, you create a region yourself with the possibility to add more functionality to the region. Plug-ins are very useful because they are reusable in every application. To make a plug-in available, go to Shared Components | Plug-ins , and click on the Export Plug-in link on the right-hand side of the page. Select the desired plug-in and file format and click on the Export Plug-in button. The plug-in can then be imported into another application. Following are the six types of plug-in: Item type plug-ins Region type plug-ins Dynamic action plug-ins Process type plug-ins Authorization scheme type plug-ins Authentication scheme type plug-ins In this Aricle we will discuss the first five types of plug-ins. Creating an item type plug-in In an item type plug-in you create an item with the possibility to extend its functionality. To demonstrate this, we will make a text field with a tooltip. This functionality is already available in APEX 4.0 by adding the following code to the HTML form element attributes text field in the Element section of the text field: onmouseover="toolTip_enable(event,this,'A tooltip')" But you have to do this for every item that should contain a tooltip. This can be made more easily by creating an item type plug-in with a built-in tooltip. And if you create an item of type plug-in, you will be asked to enter some text for the tooltip. Getting ready For this recipe you can use an existing page, with a region in which you can put some text items. How to do it... Follow these steps: Go to Shared Components | User Interface | Plug-ins . Click on the Create button. In the Name section, enter a name in the Name text field. In this case we enter tooltip. In the Internal Name text field, enter an internal name. It is advised to use the company's domain address reversed to ensure the name is unique when you decide to share this plug-in. So for example you can use com.packtpub.apex.tooltip. In the Source section, enter the following code in the PL/SQL Code text area: function render_simple_tooltip ( p_item in apex_plugin.t_page_item , p_plugin in apex_plugin.t_plugin , p_value in varchar2 , p_is_readonly in boolean , p_is_printer_friendly in boolean ) return apex_plugin.t_page_item_render_result is l_result apex_plugin.t_page_item_render_result; begin if apex_application.g_debug then apex_plugin_util.debug_page_item ( p_plugin => p_plugin , p_page_item => p_item , p_value => p_value , p_is_readonly => p_is_readonly , p_is_printer_friendly => p_is_printer_friendly); end if; -- sys.htp.p('<input type="text" id="'||p_item.name||'" name="'||p_item.name||'" class="text_field" onmouseover="toolTip_enable(event,this,'||''''||p_item.attribute_01||''''||')">');--return l_result;end render_simple_tooltip; This function uses the sys.htp.p function to put a text item (<input type="text") on the screen. On the text item, the onmouseover event calls the function toolTip_enable(). This function is an APEX function, and can be used to put a tooltip on an item. The arguments of the function are mandatory. The function starts with the option to show debug information. This can be very useful when you create a plug-in and it doesn't work. After the debug information, the htp.p function puts the text item on the screen, including the call to tooltip_enable. You can also see that the call to tooltip_enable uses p_item.attribute_01. This is a parameter that you can use to pass a value to the plug-in. That is, the following steps in this recipe. The function ends with the return of l_result. This variable is of the type apex_plugin.t_page_item_render_result. For the other types of plug-in there are dedicated return types also, for example t_region_render_result. Click on the Create Plug-in button The next step is to define the parameter (attribute) for this plug-in. In the Custom Attributes section, click on the Add Attribute button. In the Name section, enter a name in the Label text field, for example tooltip. Ensure that the Attribute text field contains the value 1 . In the Settings section, set the Type field to Text . Click on the Create button. In the Callbacks section, enter render_simple_tooltip into the Render Function Name text field. In the Standard Attributes section, check the Is Visible Widget checkbox. Click on the Apply Changes button. The plug-in is now ready. The next step is to create an item of type tooltip plug-in. Go to a page with a region where you want to use an item with a tooltip. In the Items section, click on the add icon to create a new item. Select Plug-ins . Now you will get a list of the available plug-ins. Select the one we just created, that is tooltip . Click on Next . In the Item Name text field, enter a name for the item, for example, tt_item. In the Region drop-down list, select the region you want to put the item in. Click on Next . In the next step you will get a new option. It's the attribute you created with the plug-in. Enter here the tooltip text, for example, This is tooltip text. Click on Next . In the last step, leave everything as it is and click on the Create Item button. You are now ready. Run the page. When you move your mouse pointer over the new item, you will see the tooltip. How it works... As stated before, this plug-in actually uses the function htp.p to put an item on the screen. Together with the call to the JavaScript function, toolTip_enable on the onmouseover event makes this a text item with a tooltip, replacing the normal text item. There's more... The tooltips shown in this recipe are rather simple. You could make them look better, for example, by using the Beautytips tooltips. Beautytips is an extension to jQuery and can show configurable help balloons. Visit http://plugins.jquery.com to download Beautytips. We downloaded Version 0.9.5-rc1 to use in this recipe. Go to Shared Components and click on the Plug-ins link. Click on the tooltip plug-in you just created. In the Source section, replace the code with the following code: function render_simple_tooltip ( p_item in apex_plugin.t_page_item, p_plugin in apex_plugin.t_plugin, p_value in varchar2, p_is_readonly in boolean, p_is_printer_friendly in boolean ) return apex_plugin.t_page_item_render_result is l_result apex_plugin.t_page_item_render_result; begin if apex_application.g_debug then apex_plugin_util.debug_page_item ( p_plugin => p_plugin , p_page_item => p_item , p_value => p_value , p_is_readonly => p_is_readonly , p_is_printer_friendly => p_is_printer_friendly); end if; The function also starts with the debug option to see what happens when something goes wrong. --Register the JavaScript and CSS library the plug-inuses. apex_javascript.add_library ( p_name => 'jquery.bgiframe.min', p_directory => p_plugin.file_prefix, p_version => null ); apex_javascript.add_library ( p_name => 'jquery.bt.min', p_directory => p_plugin.file_prefix, p_version => null ); apex_javascript.add_library ( p_name => 'jquery.easing.1.3', p_directory => p_plugin.file_prefix, p_version => null ); apex_javascript.add_library ( p_name => 'jquery.hoverintent.minified', p_directory => p_plugin.file_prefix, p_version => null ); apex_javascript.add_library ( p_name => 'excanvas', p_directory => p_plugin.file_prefix, p_version => null ); After that you see a number of calls to the function apex_javascript.add_library. These libraries are necessary to enable these nice tooltips. Using apex_javascript.add_library ensures that a JavaScript library is included in the final HTML of a page only once, regardless of how many plug-in items appear on that page. sys.htp.p('<input type="text" id="'||p_item.name||'"class="text_field" title="'||p_item.attribute_01||'">');-- apex_javascript.add_onload_code (p_code =>'$("#'||p_item.name||'").bt({ padding: 20 , width: 100 , spikeLength: 40 , spikeGirth: 40 , cornerRadius: 50 , fill: '||''''||'rgba(200, 50, 50, .8)'||''''||' , strokeWidth: 4 , strokeStyle: '||''''||'#E30'||''''||' , cssStyles: {color: '||''''||'#FFF'||''''||',fontWeight: '||''''||'bold'||''''||'} });'); -- return l_result; end render_tooltip; Another difference with the first code is the call to the Beautytips library. In this call you can customize the text balloon with colors and other options. The onmouseover event is not necessary anymore as the call to $().bt in the wwv_flow_javascript.add_onload_code takes over this task. The $().bt function is a jQuery JavaScript function which references the generated HTML of the plug-in item by ID, and converts it dynamically to show a tooltip using the Beautytips plug-in. You can of course always create extra plug-in item type parameters to support different colors and so on per item. To add the other libraries, do the following: In the Files section, click on the Upload new file button. Enter the path and the name of the library. You can use the file button to locate the libraries on your filesystem. Once you have selected the file, click on the Upload button. The files and their locations can be found in the following table: Libra ry Location jquery.bgiframe.min.js bt-0.9.5-rc1other_libsbgiframe_2.1.1 jquery.bt.min.js bt-0.9.5-rc1 jquery.easing.1.3.js bt-0.9.5-rc1other_libs jquery.hoverintent.minified.js bt-0.9.5-rc1other_libs Excanvas.js bt-0.9.5-rc1other_libsexcanvas_r3     If all libraries have been uploaded, the plug-in is ready. The tooltip now looks quite different, as shown in the following screenshot: In the plug-in settings, you can enable some item-specific settings. For example, if you want to put a label in front of the text item, check the Is Visible Widget checkbox in the Standard Attributes section. For more information on this tooltip, go to http://plugins.jquery.com/project/bt. Creating a region type plug-in As you may know, a region is actually a div. With the region type plug-in you can customize this div. And because it is a plug-in, you can reuse it in other pages. You also have the possibility to make the div look better by using JavaScript libraries. In this recipe we will make a carousel with switching panels. The panels can contain images but they can also contain data from a table. We will make use of another jQuery extension, Step Carousel. Getting ready You can download stepcarousel.js from http://www.dynamicdrive.com/dynamicindex4/stepcarousel.htm. However, in order to get this recipe work in APEX, we needed to make a slight modification in it. So, stepcarousel.js, arrowl.gif, and arrow.gif are included in this book. How to do it... Follow the given steps, to create the plug-in: Go to Shared Components and click on the Plug-ins link. Click on the Create button. In the Name section, enter a name for the plug-in in the Name field. We will use Carousel. In the Internal Name text field, enter a unique internal name. It is advised to use your domain reversed, for example com.packtpub.carousel. In the Type listbox, select Region . In the Source section, enter the following code in the PL/SQL Code text area: function render_stepcarousel ( p_region in apex_plugin.t_region, p_plugin in apex_plugin.t_plugin, p_is_printer_friendly in boolean ) return apex_plugin.t_region_render_result is cursor c_crl is select id , panel_title , panel_text , panel_text_date from app_carousel order by id; -- l_code varchar2(32767); begin The function starts with a number of arguments. These arguments are mandatory, but have a default value. In the declare section there is a cursor with a query on the table APP_CAROUSEL. This table contains several data to appear in the panels in the carousel. -- add the libraries and stylesheets -- apex_javascript.add_library ( p_name => 'stepcarousel', p_directory => p_plugin.file_prefix, p_version => null ); -- --Output the placeholder for the region which is used by--the Javascript code The actual code starts with the declaration of stepcarousel.js. There is a function, APEX_JAVASCRIPT.ADD_LIBRARY to load this library. This declaration is necessary, but this file needs also to be uploaded in the next step. You don't have to use the extension .js here in the code. -- sys.htp.p('<style type="text/css">'); -- sys.htp.p('.stepcarousel{'); sys.htp.p('position: relative;'); sys.htp.p('border: 10px solid black;'); sys.htp.p('overflow: scroll;'); sys.htp.p('width: '||p_region.attribute_01||'px;'); sys.htp.p('height: '||p_region.attribute_02||'px;'); sys.htp.p('}'); -- sys.htp.p('.stepcarousel .belt{'); sys.htp.p('position: absolute;'); sys.htp.p('left: 0;'); sys.htp.p('top: 0;'); sys.htp.p('}'); sys.htp.p('.stepcarousel .panel{'); sys.htp.p('float: left;'); sys.htp.p('overflow: hidden;'); sys.htp.p('margin: 10px;'); sys.htp.p('width: 250px;'); sys.htp.p('}'); -- sys.htp.p('</style>'); After the loading of the JavaScript library, some style elements are put on the screen. The style elements could have been put in a Cascaded Style Sheet (CSS ), but since we want to be able to adjust the size of the carousel, we use two parameters to set the height and width. And the height and the width are part of the style elements. -- sys.htp.p('<div id="mygallery" class="stepcarousel"style="overflow:hidden"><div class="belt">'); -- for r_crl in c_crl loop sys.htp.p('<div class="panel">'); sys.htp.p('<b>'||to_char(r_crl.panel_text_date,'DD-MON-YYYY')||'</b>'); sys.htp.p('<br>'); sys.htp.p('<b>'||r_crl.panel_title||'</b>'); sys.htp.p('<hr>'); sys.htp.p(r_crl.panel_text); sys.htp.p('</div>'); end loop; -- sys.htp.p('</div></div>'); The next command in the script is the actual creation of a div. Important here is the name of the div and the class. The Step Carousel searches for these identifiers and replaces the div with the stepcarousel. The next step in the function is the fetching of the rows from the query in the cursor. For every line found, the formatted text is placed between the div tags. This is done so that Step Carousel recognizes that the text should be placed on the panels. --Add the onload code to show the carousel -- l_code := 'stepcarousel.setup({ galleryid: "mygallery" ,beltclass: "belt" ,panelclass: "panel" ,autostep: {enable:true, moveby:1, pause:3000} ,panelbehavior: {speed:500, wraparound:true,persist:true} ,defaultbuttons: {enable: true, moveby: 1,leftnav:["'||p_plugin.file_prefix||'arrowl.gif", -5,80], rightnav:["'||p_plugin.file_prefix||'arrowr.gif", -20,80]} ,statusvars: ["statusA", "statusB", "statusC"] ,contenttype: ["inline"]})'; -- apex_javascript.add_onload_code (p_code => l_code); -- return null; end render_stepcarousel; The function ends with the call to apex_javascript.add_onload_code. Here starts the actual code for the stepcarousel and you can customize the carousel, like the size, rotation speed and so on. In the Callbacks section, enter the name of the function in the Return Function Name text field. In this case it is render_stepcarousel. Click on the Create Plug-in button. In the Files section, upload the stepcarousel.js, arrowl.gif, and arrowr.gif files. For this purpose, the file stepcarousel.js has a little modification in it. In the last section (setup:function), document.write is used to add some style to the div tag. Unfortunately, this will not work in APEX, as document.write somehow destroys the rest of the output. So, after the call, APEX has nothing left to show, resulting in an empty page. Document.write needs to be removed, and the following style elements need to be added in the code of the plug-in: sys.htp.p('</p><div id="mygallery" class="stepcarousel" style="overflow: hidden;"><div class="belt">'); In this line of code you see style='overflow:hidden'. That is the line that actually had to be included in stepcarousel.js. This command hides the scrollbars. After you have uploaded the files, click on the Apply Changes button. The plug-in is ready and can now be used in a page. Go to the page where you want this stepcarousel to be shown. In the Regions section, click on the add icon. In the next step, select Plug-ins . Select Carousel . Click on Next . Enter a title for this region, for example Newscarousel. Click on Next . In the next step, enter the height and the width of the carousel. To show a carousel with three panels, enter 800 in the Width text field. Enter 100 in the Height text field. Click on Next . Click on the Create Region button. The plug-in is ready. Run the page to see the result. How it works... The stepcarousel is actually a div. The region type plug-in uses the function sys.htp.p to put this div on the screen. In this example, a div is used for the region, but a HTML table can be used also. An APEX region can contain any HTML output, but for the positioning, mostly a HTML table or a div is used, especially when layout is important within the region. The apex_javascript.add_onload_code starts the animation of the carousel. The carousel switches panels every 3 seconds. This can be adjusted (Pause : 3000). See also For more information on this jQuery extension, go to http://www.dynamicdrive.com/dynamicindex4/stepcarousel.htm.

(For more resources related to this topic, see here.) Web apps are now a major part of today's World Wide Web. Keeping them safe and secure is the prime focus of webmasters. Building web apps from scratch can be a tedious task, and there can be small bugs in the code that can lead to a security breach. This is where web apps jump in and help you secure your application. Web app penetration testing can be implemented at various fronts such as the frontend interface, database, and web server. Let us leverage the power of some of the important tools of Kali that can be helpful during web app penetration testing. WebScarab proxy WebScarab is an HTTP and HTTPS proxy interceptor framework that allows the user to review and modify the requests created by the browser before they are sent to the server. Similarly, the responses received from the server can be modified before they are reflected in the browser. The new version of WebScarab has many more advanced features such as XSS/CSRF detection, Session ID analysis, and Fuzzing. Follow these three steps to get started with WebScarab: To launch WebScarab, browse to Applications | Kali Linux | Web applications | Web application proxies | WebScarab. Once the application is loaded, you will have to change your browser's network settings. Set the proxy settings for IP as 127.0.0.1 and Port as 8008: Save the settings and go back to the WebScarab GUI. Click on the Proxy tab and check Intercept request. Make sure that both GET and POST requests are highlighted on the left-hand side panel. To intercept the response, check Intercept responses to begin reviewing the responses coming from the server. Attacking the database using sqlninja sqlninja is a popular tool used to test SQL injection vulnerabilities in Microsoft SQL servers. Databases are an integral part of web apps hence, even a single flaw in it can lead to mass compromising of information. Let us see how sqlninja can be used for database penetration testing. To launch SQL ninja, browse to Applications | Kali Linux | Web applications | Database Exploitation | sqlninja. This will launch the terminal window with sqlninja parameters. The important parameter to look for is either the mode parameter or the –m parameter: The –m parameter specifies the type of operation we want to perform over the target database.Let us pass a basic command and analyze the output: root@kali:~#sqlninja –m test Sqlninja rel. 0.2.3-r1 Copyright (C) 2006-2008 icesurfer [-] sqlninja.conf does not exist. You want to create it now ? [y/n] This will prompt you to set up your configuration file (sqlninja.conf). You can pass the respective values and create the config file. Once you are through with it, you are ready to perform database penetration testing. The Websploit framework Websploit is an open source framework designed for vulnerability analysis and penetration testing of web applications. It is very much similar to Metasploit and incorporates many of its plugins to add functionalities. To launch Websploit, browse to Applications | Kali Linux | Web Applications | Web Application Fuzzers | Websploit. We can begin by updating the framework. Passing the update command at the terminal will begin the updating process as follows: wsf>update [*]Updating Websploit framework, Please Wait… Once the update is over, you can check out the available modules by passing the following command: wsf>show modules Let us launch a simple directory scanner module against www.target.com as follows: wsf>use web/dir_scanner wsf:Dir_Scanner>show options wsf:Dir_Scanner>set TARGET www.target.com wsf:Dir_Scanner>run Once the run command is executed, Websploit will launch the attack module and display the result. Similarly, we can use other modules based on the requirements of our scenarios. Summary In this article, we covered the following sections: WebScarab proxy Attacking the database using sqlninja The Websploit framework Resources for Article: Further resources on this subject: Installing VirtualBox on Linux [Article] Linux Shell Script: Tips and Tricks [Article] Installing Arch Linux using the official ISO [Article]