Entity Framework Migrations are handled from the package manager console in Visual Studio. The usage is shown in various tutorials, but I haven’t found a complete list of the commands available and their usage, so I created my own. There are four available commands. Enable-Migrations: Enables Code First Migrations in a project. Add-Migration: Scaffolds a migration script for any pending model changes. Update-Database: Applies any pending migrations to the database. Get-Migrations: Displays the migrations that have been applied to the target database. The information here is the output of running get-help command-name -detailed for each of the commands in the package manager console (running EF 4.3.1). I’ve also added some own comments where I think some information is missing. My own comments are placed under the Additional Information heading. Please note that all commands should be entered on the same line. I’ve added line breaks to avoid vertical scrollbars. Enable-Migrations Enables Code First Migrations in a project. Syntax Enable-Migrations [-EnableAutomaticMigrations] [[-ProjectName] ] [-Force] [] Description Enables Migrations by scaffolding a migrations configuration class in the project. If the target database was created by an initializer, an initial migration will be created (unless automatic migrations are enabled via the EnableAutomaticMigrations parameter). Parameters -EnableAutomaticMigrations Specifies whether automatic migrations will be enabled in the scaffolded migrations configuration. If ommitted, automatic migrations will be disabled. -ProjectName Specifies the project that the scaffolded migrations configuration class will be added to. If omitted, the default project selected in package manager console is used. -Force Specifies that the migrations configuration be overwritten when running more than once for given project. This cmdlet supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction, WarningVariable, OutBuffer and OutVariable. For more information, type: get-help about_commonparameters. Remarks To see the examples, type: get-help Enable-Migrations -examples. For more information, type: get-help Enable-Migrations -detailed. For technical information, type: get-help Enable-Migrations -full. Additional Information The flag for enabling automatic migrations is saved in the Migrations\Configuration.cs file, in the constructor. To later change the option, just change the assignment in the file. public Configuration() { AutomaticMigrationsEnabled = false; } Add-Migration Scaffolds a migration script for any pending model changes. Syntax Add-Migration [-Name] [-Force] [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] [-ConnectionStringName ] [-IgnoreChanges] [] Add-Migration [-Name] [-Force] [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] -ConnectionString -ConnectionProviderName [-IgnoreChanges] [] Description Scaffolds a new migration script and adds it to the project. Parameters -Name Specifies the name of the custom script. -Force Specifies that the migration user code be overwritten when re-scaffolding an existing migration. -ProjectName Specifies the project that contains the migration configuration type to be used. If ommitted, the default project selected in package manager console is used. -StartUpProjectName Specifies the configuration file to use for named connection strings. If omitted, the specified project’s configuration file is used. -ConfigurationTypeName Specifies the migrations configuration to use. If omitted, migrations will attempt to locate a single migrations configuration type in the target project. -ConnectionStringName Specifies the name of a connection string to use from the application’s configuration file. -ConnectionString Specifies the the connection string to use. If omitted, the context’s default connection will be used. -ConnectionProviderName Specifies the provider invariant name of the connection string. -IgnoreChanges Scaffolds an empty migration ignoring any pending changes detected in the current model. This can be used to create an initial, empty migration to enable Migrations for an existing database. N.B. Doing this assumes that the target database schema is compatible with the current model. This cmdlet supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction, WarningVariable, OutBuffer and OutVariable. For more information, type: get-help about_commonparameters. Remarks To see the examples, type: get-help Add-Migration -examples. For more information, type: get-help Add-Migration -detailed. For technical information, type: get-help Add-Migration -full. Update-Database Applies any pending migrations to the database. Syntax Update-Database [-SourceMigration ] [-TargetMigration ] [-Script] [-Force] [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] [-ConnectionStringName ] [] Update-Database [-SourceMigration ] [-TargetMigration ] [-Script] [-Force] [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] -ConnectionString -ConnectionProviderName [] Description Updates the database to the current model by applying pending migrations. Parameters -SourceMigration Only valid with -Script. Specifies the name of a particular migration to use as the update’s starting point. If ommitted, the last applied migration in the database will be used. -TargetMigration Specifies the name of a particular migration to update the database to. If ommitted, the current model will be used. -Script Generate a SQL script rather than executing the pending changes directly. -Force Specifies that data loss is acceptable during automatic migration of the database. -ProjectName Specifies the project that contains the migration configuration type to be used. If ommitted, the default project selected in package manager console is used. -StartUpProjectName Specifies the configuration file to use for named connection strings. If omitted, the specified project’s configuration file is used. -ConfigurationTypeName Specifies the migrations configuration to use. If omitted, migrations will attempt to locate a single migrations configuration type in the target project. -ConnectionStringName Specifies the name of a connection string to use from the application’s configuration file. -ConnectionString Specifies the the connection string to use. If omitted, the context’s default connection will be used. -ConnectionProviderName Specifies the provider invariant name of the connection string. This cmdlet supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction, WarningVariable, OutBuffer and OutVariable. For more information, type: get-help about_commonparameters. Remarks To see the examples, type: get-help Update-Database -examples. For more information, type: get-help Update-Database -detailed. For technical information, type: get-help Update-Database -full. Additional Information The command always runs any pending code-based migrations first. If the database is still incompatible with the model the additional changes required are applied as an separate automatic migration step if automatic migrations are enabled. If automatic migrations are disabled an error message is shown. Get-Migrations Displays the migrations that have been applied to the target database. Syntax Get-Migrations [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] [-ConnectionStringName ] [] Get-Migrations [-ProjectName ] [-StartUpProjectName ] [-ConfigurationTypeName ] -ConnectionString -ConnectionProviderName [] Description Displays the migrations that have been applied to the target database. Parameters -ProjectName Specifies the project that contains the migration configuration type to be used. If ommitted, the default project selected in package manager console is used. -StartUpProjectName Specifies the configuration file to use for named connection strings. If omitted, the specified project’s configuration file is used. -ConfigurationTypeName Specifies the migrations configuration to use. If omitted, migrations will attempt to locate a single migrations configuration type in the target project. -ConnectionStringName Specifies the name of a connection string to use from the application’s configuration file. -ConnectionString Specifies the the connection string to use. If omitted, the context’s default connection will be used. -ConnectionProviderName Specifies the provider invariant name of the connection string. This cmdlet supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction, WarningVariable, OutBuffer and OutVariable. For more information, type: get-help about_commonparameters. Remarks To see the examples, type: get-help Get-Migrations -examples. For more information, type: get-help Get-Migrations -detailed. For technical information, type: get-help Get-Migrations -full. Additional Information The powershell commands are complex powershell functions, located in the tools\EntityFramework.psm1 file of the Entity Framework installation. The powershell code is mostly a wrapper around the System.Data.Entity.Migrations.MigrationsCommands found in the tools\EntityFramework\EntityFramework.PowerShell.dll file. First a MigrationsCommands object is instantiated with all configuration parameters. Then there is a public method on the MigrationsCommands object for each of the available commands.

My colleague Tom McGinn recently published 10 Time Savers in NetBeans, an excellent overview of tips that everyone using NetBeans should read. For those of us who are keyboard oriented (i.e., we hate the mouse because it breaks our workflow), here is an appendix to Tom's article, listing the very newest keyboard shortcuts, available in NetBeans IDE 7. Most are new or changed in NetBeans IDE 7.2, while the last one is new but unchanged from NetBeans IDE 7.1. Alt + Scroll Up/Down. Increase/decrease the font size. Font resizing, which was first introduced in NetBeans IDE 7.1, was initially done by holding down the Ctrl key while scrolling. However, this conflicted with other actions, as explained in issue 212484. Following discussions with the NetBeans community, the Ctrl key was changed for the Alt key, and now, when you hold down the Alt key and then scroll up/down, in any file, the font size will increase/decrease. Alt + Shift + Page Up/Down. Quickly move entire code elements, i.e., statements and class members, up or down. Take the following situation. The cursor is on the first line below; if you were to use the standard Alt + Shift + Down, only the line would be moved down, which would immediately create an error in the editor because now the class cannot be compiled anymore. However, if you use Alt + Shift + Page Down instead (i.e., Page Down instead of simply Down), the entire method will move downwards, over the method below that, and will then appear below the method that is currently below it. In other words, the move action now has semantic knowledge of the code being moved, as well as semantic knowledge of the code around it. A similarly semantic-aware keyboard shortcut, though not new in NetBeans IDE 7, is Alt + Shift + Period, which lets you semantically expand the selection from the currently selected word to the next level of semantic knowledge, e.g., method or class, and back again via Alt + Shift + Comma. Alt + Backspace. Quickly remove the enclosing parts of a nested statement. Put the cursor within the word "for", or "if", or "else", for example, then press Alt + Backspace and the popup below is displayed. Mouse down or up in the list and then press Enter to confirm. Ctrl + Shift + M. Add/remove a bookmark to/from the Bookmarks Window. As always, you can set bookmarks in your code. However, now, when you do so, the bookmarks are, in addition to being marked in the file, added to the new Bookmarks Window (available via Window | Navigating | Bookmarks). From the Bookmarks Window, you can now jump across all your files and all your projects so that you can, for example, create a task-oriented track through your projects: In a related change, when you now use Ctrl + Shift + Period or Ctrl + Shift + Comma, to toggle back and forward between bookmarks, this handy popup appears, listing all the bookmarks found within the Bookmarks Window: Alt + Shift + F. The "Reformat" action can now be used across multiple projects, packages, and classes, for the first time. That means that when you use the old Alt + Shift + F while multiple nodes are selected in the Projects window, all files within the selected nodes will be reformatted at the same time. Ctrl + Z. The "Undo" keyboard shortcut now applies to refactorings too, for the first time. In previous releases, you needed to use a separate action especially for undoing refactorings, which was very hidden in the Refactoring menu and therefore hard to find, and therefore not frequently used because typically you wouldn't know it existed. Ctrl + Space. Once you have pressed Ctrl-F or Ctrl-H to open the Find bar or the Search bar at the bottom of any file (not only Java source files, but also HTML files, for example), you can press Ctrl + Space which lets you use code completion within the Find field, which can be very useful to get a quick overview of the items you could be trying to find. In the Debugger, the same is true in the New Breakpoint dialog. Ctrl + Shift + R. Change the cursor to a block selector. Then put the cursor next to the top left of the block and Shift+Click its bottom right corner. You now have a block, which you can manipulate, e.g., move or cut or copy or delete or change all the lines within the block. Start typing while having a block selected and all the lines will change simultaneously. Applies to all file types, not only Java source files, as can be seen here: Note: And, a final tip, if you go to the Help menu in NetBeans IDE, you'll find the updated NetBeans IDE Keyboard Shortcut Card in PDF format, ideal for printing out and hanging in a nice frame in your workspace!

DrupalCon Munich is next week, and I am lucky enough to be going. As part of preparing for the conference, I thought it would be worthwhile to see just how easy (or difficult) it would be to migrate an existing Drupal site to Windows Azure Web Sites. So, in this post, I’ll do just that. Fortunately, because Windows Azure Web Sites supports both PHP and MySQL, the migration process is relatively straightforward. And, because Drupal and PHP run on any platform, the process I’ll describe should work for moving Drupal to Windows Azure Web Sites regardless of what platform you are moving from. Of course, Drupal installations can vary widely, so YMMV. I tested the instructions below on relatively small (and simple) Drupal installation running on CentOS 5. (Unfortunately, I won’t be using Drush since it isn’t supported on Windows Azure Websites.) If you are considering moving a large and complex Drupal application, may want to consider moving to Windows Azure Cloud Services (more information about that here: Migrating a Drupal Site from LAMP to Windows Azure). Before getting started, it’s worth noting that Windows Azure Websites lets you run up to 10 Web Sites for free in a multitenant environment. And, you can seamlessly upgrade to private, reserved VM instances as your traffic grows. To sign up, try the Windows Azure 90-day free trial. 1. Create a Windows Azure Web Site and MySQL database There is a step-by-step tutorial on http://www.windowsazure.com that walks you through creating a new website and a MySQL database, so I’ll refer you there to get started: Create a PHP-MySQL Windows Azure web site and deploy using Git. If you intend to use Git to publish your Drupal site, then go ahead and follow the instructions for setting up a Git repository. Make sure to follow the instructions in the Get remote MySQL connection information section as you will need that information later. You can ignore the remainder of the tutorial for the purposes of deploying your Drupal site, but if you are new to Windows Azure Web Sites (and to Git), you might find the additional reading informative. Ok, now you have a new website with a MySQL database, your have your MySQL database connection information, and you have (optionally) created a remote Git repository and made note of the Git deployment instructions. Now you are ready to copy your database to MySQL in Windows Azure Web Sites. 2. Copy database to MySQL in Windows Azure Web Sites I’m sure there is more than one way to copy your Drupal database, but I found the mysqldump tool to be effective and easy to use. To copy from a local machine to Windows Azure Web Sites, here’s the command I used: mysqldump -u local_username --password=local_password drupal | mysql -h remote_host -u remote_username --password=remote_password remote_db_name You will, of course, have to provide the username and password for your existing Drupal database, and you will have to provide the hostname, username, password, and database name for the MySQL database you created in step 1. This information is available in the connection string information that you should have noted in step 1. i.e. You should have a connection string that looks something like this: Database=remote_db_name;Data Source=remote_host;User Id=remote_username;Password=remote_password Depending on the size of your database, the copying process could take several minutes. Now your Drupal database is live in Windows Azure Websites. Before you deploy your Drupal code, you need to modify it so it can connect to the new database. 3. Modify database connection info in settings.php Here, you will again need your new database connection information. Open the /drupal/sites/default/setting.php file in your favorite text editor, and replace the values of ‘database’, ‘username’, ‘password’, and ‘host’ in the $databases array with the correct values for your new database. When you are finished, you should have something similar to this: $databases = array ( 'default' => array ( 'default' => array ( 'database' => 'remote_db_name', 'username' => 'remote_username', 'password' => 'remote_password', 'host' => 'remote_host', 'port' => '', 'driver' => 'mysql', 'prefix' => '', ), ), ); Be sure to save the settings.phpfile, then you are ready to deploy. 4. Deploy Drupal code using Git or FTP The last step is to deploy your code to Windows Azure Web Sites using Git or FTP. If you are using FTP, you can get the FTP hostname and username from you website’s dashboard. Then, use your favorite FTP client to upload your Drupal files to the /site/wwwroot folder of the remote site. If you are using Git, you need to set up a Git repository in Windows Azure Web Sites (steps for this are in the tutorial mentioned earlier). And, you will need Git installed on your local machine. Then, just follow the instructions provided after you created the repository: One note about using Git here: depending on your Git settings, your .gitignore file (a hidden file and a sibling to the .git folder created in your local root directory after you executed git commit), some files in your Drupal application may be ignored. In my case, all the files in the sites directory were ignored. If this happens, you will want to edit the .gitignore file so that these files aren’t ignored and redeploy. After you have deployed Drupal to Windows Azure Web Sites, you can continue to deploy updates via Git or FTP. Related information If you are looking for more information about Windows Azure Web Sites, these posts might be helpful: Windows Azure Websites- A PHP Perspective Windows Azure Websites, Web Roles, and VMs- When to use which- Configuring PHP in Windows Azure Websites with .user.ini Files One last thing you might consider, depending on your site, is using the Windows Azure Integration Module to store and serve your site’s media files.

This article will provide you with 8 ways to improve your production support skills which may help you better enjoy your IT support job.

I still see a lot of fear out there in the development and operations communities with regards to being able to rollback failed software deploys. People talk about the difficulty of rolling back, the need to always be rolling forward in the case of error, and the difficulty in testing rollback procedures. Having written software and been responsible for deploying that software on very high availability environments, this isn’t however a world I’ve experienced in the slightest. In my experience: It’s been easier to rollback to a known state than roll forward; It’s been riskier to roll forward if a deploy is going south than it was to roll backwards; It’s much easier to test and gain confidence in a rollback than it is in the roll forward. I think a lot of the mis-conceptions people have come from the fact that the average development simply does not give rollback enough importance and focus in their development and release management process. This is a shame as rolling back is potentially your best friend with regards to improving robustness of systems and keeping customers happy. With a good rollback you can simply hit the red button at the first sign of trouble and have the system back up and running whilst you look into the situation. It may be that you’ve overreacted in pulling the release, but that’s generally better than breaking something. With that said, here are a few tips that I’ve found to work well: How To Do Rollback Well The most important step is to implement an architecture that supports the need to rollback. For instance, componentised, service based architectures lend themselves well to this. Persistent message queues and asynchronous services allow you to bring components down for rollback without impacting the main user base. Work towards something like the Blue-Green release pattern such that your application can stay available whilst you are working on one half of the system. Test roll backs as thoroughly as your roll outs via the QA process. Throughout development and testing, attempt to get as much, or even more, confidence in your rollback as you have in your release. Foster a mindset that change is good, but the route back to the working system is much more important. People generally prefer working software over new features. Design the rollbacks and roll forwards to both work idempotently. Ensure you can roll back a bad deploy and then roll it forward again when the time is right. Neither step should be destructive as we should be accepting that rollback has a high degree of probability. Have your QA temas explicitly test roll out, roll back, roll out to further gain confidence and experience in the process. Any observations, problems etc should be fed back and the change should not be signed off till the rollback is a high quality one. Document the roll back procedures. It’s likely there will be a degree of stress involved if we need to roll back the production system, so take the time before the release to write up how to run the rollback process, what to check, and what to do in potential failure situations. e.g. If the database deploy fails, run script x.sql and check conditions a, b, c. If condition b has occured, execute y.sql. 10 minutes anticipation of failure modes before the change can save a lot of time during a crisis. Take small gradual steps in your releases. Release intermediate steps behind feature toggles so that we can slowly but surely gain confidence in the feature that we are releasing whilst having the minimal possible rollbacks. Try to upgrade components individually rather than in parallel. Have documented steps in place to assert that the rollback process has put the system back into it’s original good state – something simple like checking the net file size, running a diff, or checking the number of database rows. You’ll then want to back this up with as many automated and manual sanity tests as possible to ensure the rollback was correct. You’ll notice that none of the above come for free. Each of them take time and effort, but in my experience this has always been worth the time and effort with regards to moving the applications I’m responsible for slowly but surely and with confidence.

Learn how to use spring profiles in an XML config with this great tutorial.

In my post about JaCoCo and MavenI wrote about the problems of using the JaCoCo Maven plugin in multimodule Maven projects because of having one report for each module separately instead of one report for all modules, and how it can be fixed using JaCoCo Ant Task. In this post we are going to see how to use the JaCoCo Jenkins plugin to achieve the same goal of Ant Tasks and have overall code coverage statistics for all modules. The first step is installing the JaCoCo Jenkins plugin. Go to Jenkins -> Manage Jenkins -> Plugin Manager -> Available and find JaCoCo Plugin The next step, if it is not done already, is configuring your JaCoCo Maven plugin into parent pom: org.jacoco jacoco-maven-plugin ${jacoco.version} prepare-agent report prepare-package report And finally a post-action must be configured to the job responsible for packaging the application. Note that in previous pom file reports are generated just before the package goal is executed. Go to Configure -> Post-build Actions -> Add post-build action -> Record JaCoCo coverage report. Then we have to set folders or files containing JaCoCoXML reports, which are using the previous pom to **/target/site/jacoco/jacoco*.xml, and also set when we consider that a build is healthy in terms of coverage. Then we can save the job configuration and run the build project. After the project is build, a new report will appear just under the test result trend graph, called code coverage trend, where we can see the code coverage of all project modules. From the left menu, you can enter into Coverage Report and see code coverage of each module separately. Furthermore, visiting the Jenkins main page will give you a nice quick overview of a job when you mouse over the weather icon as shown: Keep in mind that this approach for merging code coverage files will only work if you are using Jenkins as a CI system. Ant Task is a more generic solution and can also be used with the JaCoCo Jenkins plugin. We Keep Learning, Alex.

Situation It’s Thursday/Friday evening, the daily version / master branch was deemed too risky to install, and you decide to wait for Sunday/Monday with the deploy to production. There’s a new critical bug found in production. We do not want to install the bug on top of all the other changes, because of the risk factor. What do we do? Develop the fix on top of the production branch, in our local machine, git push, and deploy the fix, without all the other changes. How can I do this? My example uses a Play Framework service, but that’s immaterial. gitk –all – review the situation Suppose the latest version deployed in prod is 1.2.3, and master has some commits after that. You checkout this version: git checkout 1.2.3 Create a new branch for this hotfix. git checkout -b 1.2.3_hotfix1 Fix the bug locally, and commit. Test it locally. git push On the production machine: git fetch (not pull!) sudo service play stop git checkout 1.2.3_hotfix1 sudo service play start Test on production Merge the fix back to master: git checkout master git merge 1.2.3_hotfix1 git push Clean up the local branch: git branch -d 1.2.3_hotfix1 (Note: the branch will still be saved on origin, you’re not losing any information by deleting it locally)

Code coverage is an important measurement used during our development that describes the degree to which source code is tested. In this post I am going to explain how to run code coverage using Maven and JaCoCo plugins in multi-module projects. JaCoCo is a code coverage library for Java, which has been created by the EclEmma team. It has a plugin for Eclipse, and can be run with Ant and Maven too. Now we will focus only on a Maven approach. In a project with only one module is as easy as registering a build plugin: org.jacoco jacoco-maven-plugin 0.5.7.201204190339 prepare-agent report prepare-package report And now running mvn package in site/jacoco directory, a coverage report will be present in different formats. But with multimodule projects a new problem arises. How do we merge the metrics of all subprojects into only one file so we can have a quick overview of all subprojects? For now the Maven JaCoCo Plugin does not support it. There are many alternatives and I am going to cite the most common: Sonar. It has the disadvantage that you need to install Sonar (maybe you are already using it, but maybe not). Jenkins. The plugin for JaCoCo is still under development. Moreover you need to run a build job to inspect your coverage. This is good in terms of continuous integration but could be a problem if you are trying to "catch" some piece of code that have not been covered with previously implemented tests. Arquillian JaCoCo Extension. Arquillian is a container test framework that has an extension which during test execution can capture the coverage. It's a good option if you are using Arquillian. The disadvantage is that maybe your project does not require a container. Ant. You can use an Ant task with Maven. JaCoCo Ant tasks can merge results from multiple JaCoCo file results. Note that this is the most generic solution, and this is the chosen approach that we are going to use. The first thing to do is add a JaCoCo plugin to the parent pom so all projects could generate a coverage report. Of course, if there are modules which do not require coverage, the plugin definition should be changed from parent pom to specific projects. org.jacoco jacoco-maven-plugin 0.5.7.201204190339 prepare-agent report prepare-package report The next step is creating a specific submodule for appending all results of the JaCoCo plugin by using an Ant task. I suggest using something like project-name-coverage. Then let's open generated pom.xml and we are going to insert the required plugins to join all coverage information. To append them. As we have already written we are going to use a JaCoCo Ant task which has the ability to open all JaCoCo output files and append all their content into one. So the first thing to do is download the jar which contains the JaCoCo Ant task. To automate the download process, we are going to use maven dependency plugin: org.apache.maven.plugins maven-dependency-plugin jacoco-dependency-ant copy process-test-resources false org.jacoco org.jacoco.ant ${jacoco.version} true ${basedir}/target/jacoco-jars During process-test-resources phase Jacoco Ant artifact will be downloaded and copied to the target directory so it can be registered into the pom without worrying about the jar location. We also need a way to handle Ant tasks from Maven. And this is as simple as using maven antrun plugin, which you can specify any ant command in its configuration section. See next simple example: org.apache.maven.plugins maven-antrun-plugin 1.6 compile run Notice that we can specify any Ant task in the target tag. And now we are ready to start configuring the JaCoCo Ant task. The JaCoCo report plugin requires you set the location of the build directory, class directory, source directory or generated-source directory. For this purpose we are going set them as properties. ../projectA/target ../projectB/target ../projectA/target/classes ../projectB/target/classes ../projectA/src/main/java ../projectB/src/main/java ../projectA/target/generated-sources/annotations ../projectB/target/generated-sources/annotations And now the Ant task part which will go into target tag of the antrun plugin. First we need to define report task. Do you see that org.jacoco.ant.jar file is downloaded by the dependency plugin? You don't need to worry about copying it manually. Then we are going to call report task as defined in taskdef section. Within the executiondata element, we specify locations where JaCoCo execution data files are stored. By default this is the target directory, and for each project we need to add one entry for each submodule. The next element is structure. This element defines the report structure, and can be defined with a hierarchy of group elements. Each group should contain class files and source files of all projects that belongs to that group. In our example only one group is used. And finally we are setting output format using html, xml and csv tags. Complete Code: org.apache.maven.plugins maven-antrun-plugin 1.6 post-integration-test run org.jacoco org.jacoco.ant ${jacoco.version} And now simply run mvn clean verify and in my-project-coverage/target/coverage-report, a report with code coverage of all projects will be presented. Hope you find this post useful. We Keep Learning, Alex.

If you have already installed Ubuntu 12.04 you probably have realized that Sun java(oracle java) does not come prepacked with Ubuntu like it used to be , instead OpenJDK comes with it. Here is how you can install Oracle java on Ubuntu 12.04 manually. Download jdk-6u32-linux-x64.bin from this link. If you have used 32-bit Ubuntu installation, download jdk-6u32-linux-x32.bin instead. To make the downloaded bin file executable use the following command chmod +x jdk-6u32-linux-x64.bin To extract the bin file use the following command ./jdk-6u32-linux-x64.bin Using the following command create a folder called "jvm" inside /usr/lib if it is not already existing sudo mkdir /usr/lib/jvm Move the extracted folder into the newly created jvm folder sudo mv jdk1.6.0_32 /usr/lib/jvm/ To install the Java source use following commands sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_32/bin/javac 1 sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_32/bin/java 1 sudo update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.6.0_32/bin/javaws 1 To make this default java sudo update-alternatives --config javac sudo update-alternatives --config java sudo update-alternatives --config javaws To make symlinks point to the new Java location use the following command ls -la /etc/alternatives/java* To verify Java has installed correctly use this command java -version

This is the second article of the series on Spring Integration. This article builds on top of the first article where we introduced Spring Integration. Context setting In the first article, we created a simple java application where A message was sent over a channel, It was intercepted by a service i.e. POJO and modified. It was then sent over a different channel The modified message was read from the channel and displayed. However, in doing this - keeping in mind that we were merely introducing the concepts there - we wrote some Spring specific code in our application i.e. the test classes. In this article we will take care of that and make our application code as insulated from Spring Integration api as possible. This is done by, what Spring Integration calls gateways. Gateways exist for the sole purpose of abstracting messaging related "plumbing" code away from "business" code. The business logic might really not care whether a functionality is being achieved be sending a message over a channel or by making a SOAP call. This abstraction - though logical and desirable - have not been very practical, till now. It is probably worth having a quick look at the Spring Integration Reference Manual at this point. However, if you are just getting started with Spring Integration, you are perhaps better off following this article for the moment. I would recommend you get your hands dirty before returning to reference manual, which is very good but also very exhaustive and hence could be overwhelming for a beginner. The gateway could be a POJO with annotations (which is convenient but in my mind beats the whole purpose) or with XML configurations (can very quickly turn into a nightmare in any decent sized application if unchecked). At the end of the day it is really your choice but I like to go the XML route. The configuration options for both styles are detailed out in this section of the reference implementation. Spring Integration with Gateways So, let's create another test with gateway throw in for our HelloWorld service (refer to the first article of this series for more context). Let's start with the Spring configuration for the test. File: src/test/resources/org/academy/integration/HelloWorld1Test-context.xml In this case, all that is different is that we have added a gateway. This is an interface called org.academy.integration.Greetings. It interacts with both "inputChannel" and "outputChannel", to send and read messages respectively. Let's write the interface. File: /src/main/java/org/academy/integration/Greetings.java package org.academy.integration; public interface Greetings { public void send(String message); public String receive(); } And then we add the implementation of this interface. Wait. There is no implementation. And we do not need any implementation. Spring uses something called GatewayProxyFactoryBean to inject some basic code to this gateway which allows it to read the simple string based message, without us needing to do anything at all. That's right. Nothing at all. Note - You will need to add more code for most of your production scenarios - assuming you are not using Spring Integration framework to just push around strings. So, don't get used to free lunches. But, while it is here, let's dig in. Now, lets write a new test class using the gateway (and not interact with the channels and messages at all). File: /src/test/java/org/academy/integration/HelloWorld1Test.java package org.academy.integration; import static org.junit.Assert.*; import org.junit.Test; import org.junit.runner.RunWith; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration public class HelloWorld1Test { private final static Logger logger = LoggerFactory .getLogger(HelloWorld1Test.class); @Autowired Greetings greetings; @Test public void test() { greetings.send("World"); assertEquals(greetings.receive(), "Hello World"); logger.debug("Spring Integration with gateways."); } } Our test class is much cleaner now. It does not know about channels, or messages or anything related to Spring Integration at all. It only knows about a greetings instance - to which it gave some data by .send() method - and got modified data back by .receive() method. Hence, the business logic is oblivious of the plumbing logic, making for a much cleaner code. Now, simply type "mvn -e clean install" (or use m2e plugin) and you should be able to run the unit test and confirm that given string "World" the HelloWorld service indeed returns "Hello World" over the entire arrangement of channels and messages. Again, something optional but I highly recommend, is to run "mvn -e clean install site". This - assuming you have correctly configured some code coverage tool (cobertura in my case) will give you a nice HTML report showing the code coverage. In this case it would be 100%. I have blogged a series on code quality which deals this subject in more detail, but to cut long story short, it is very important for me to ensure that whatever coding practice / framework I use and recommend use, complies to some basic code quality standards. Being able to unit test and measure that is one such fundamental check that I do. Needless to say, Spring in general (including Spring integration) passes that check with flying colours. Conclusion That's it for this article. Happy coding.

I (https://github.com/kelemen) have been (and I still do) use Maven for development of Java code. My main reason for using Maven for development is its great NetBeans IDE support, so that I don't need to maintain IDE project files separately. As much as I like this support in the Maven world, I feel the limits of Maven every day I use it. Since I first saw the Gradle project, I knew that this is the least that I've always wanted from a build tool. So I started to look for NetBeans IDE support for Gradle. To my sadness there is only support for Eclipse and Idea. Aside from the fact that I prefer to use NetBeans IDE, I felt the IDE support to be limited for Gradle, (although the last time I read about Gradle support in IDEA, it seemed promising). Not long ago, I came across Geertjan's plugin and I felt that that writing such plugin is possible without enormous effort. So I downloaded his sources and started to analyze them and rewrite the plugin, so that it works with most Gradle scripts. There are many new features available in my version, such as these: slow tasks are done in a background thread source paths are retrieved from the model "test single" Screenshots: Project menus: Project dependencies: Project debug test: However, I removed subprojects and now each project needs to be opened manually, it is more efficient if you don't plan to edit all the subprojects; the drawback is that you cannot open projects without a build.gradle. The main problem with Gradle daemon performance is that on the first project load, Gradle downloads every single dependency. After that, I found the performance acceptable (especially after I implemented caching of already loaded projects). I have tested it with a relatively large project (>60 subprojects, lots of Java code): It took me about 2 minutes to load the project which seems ok to me for such an enormous project. Other than the project loading, the performance depends on NetBeans which is good. How to try it There is currently no compiled version of the plugin, so you have to compile it for yourself, if you want to try it. You can clone/download the sources from here: https://github.com/kelemen/netbeans-gradle-project After downloading the sources, open the project in NetBeans IDE. There generally two approaches you could consider: Generate the .nbm file (by choosing "Create NBM" in the project's popup) and install the plugin as you would do with any other third-party plugin. "Run" the project. This is the safest thing to do because this will start a new NetBeans instance with a brand new user directory (in the build folder). This way your own NetBeans installation will be unaffected. Help I would appreciate I'm pretty new to the NetBeans APIs (i.e., this is my first time using them), so someone might help me with the project dependencies (possibly Mavenize the plugin). And if it is possible, allow for the plugin to rely on a user specified installation of Gradle (there is some risk in it because Gradle does not seem to be very backward compatible). If you happen to know the Project API in NetBeans well, that could prove really helpful, so that I don't need to spend days figuring out, how things need to be done in the API. How to contact me You can contact me through my GitHub account: https://github.com/kelemen

a central concept of the eclipse framework is the concept of a workspace. the workspace holds project and project references, among with other settings. i’m using multiple workspaces all the time, and in parallel. how to know which workspace i’m using? by default, the codewarrior eclipse ide main window comes up like this: default codewarrior eclipse main frame if i have multiple ide’s open, it is hard to tell which workspace is used in which window,. showlocation startup option eclipse supports many startup options, a list can be found here . the solution is to use the -showlocation startup argument. as many other programs, eclipse supports different command line arguments. so i have added -showlocation in the shortcut used to launch eclipse: showlocation startup parameter now the workspace is visible in the eclipse title bar: workspace location in frame title another solution is to add -showlocation to the eclipse.ini file located inside the eclipse folder: cwide.ini with -showlocation additionally it is possible to display a name while ‘tabbing’ through the windows. for this i specify a name under window > preferences > general > workspace : workspace name shown in window title with this that name is shown while tabbing through the windows (shown below with windows 7): workspace title in tabbing preview another use of the is while hovering over the window taskbar (windows 7): taskbar preview with workspace name happy showing

@XmlRootElement is an annotation that people are used to using with JAXB (JSR-222). It's purpose is to uniquely associate a root element with a class. Since JAXB classes map to complex types, it is possible for a class to correspond to multiple root elements. In this case @XmlRootElement can not be used and people start getting a bit confused. In this post I'll demonstrate how @XmlElementDecl can be used to map this use case. XML Schema The XML schema below contains three root elements: customer, billing-address, and shipping-address. The customer element has an anonymous complex type, while billing-address and shipping-address are of the same named type (address-type). createBillingAddress(AddressType value) { return new JAXBElement(_BillingAddress_QNAME, AddressType.class, null, value); } @XmlElementDecl(namespace = "http://www.example.org/customer", name = "shipping-address") public JAXBElement createShippingAddress(AddressType value) { return new JAXBElement(_ShippingAddress_QNAME, AddressType.class, null, value); } } package-info The package-info class is used to specify the namespace mapping (see JAXB & Namespaces). @XmlSchema(namespace = "http://www.example.org/customer", elementFormDefault = XmlNsForm.QUALIFIED) package org.example.customer; import javax.xml.bind.annotation.*; Unmarshal Operation Now we look at the impact of the type of root element when unmarshalling XML. customer.xml Below is a sample XML document with customer as the root element. Remember the customer element had an anonymous complex type. 1 Any Street 2 Another Road shipping.xml Here is a sample XML document with shipping-address as the root element. The shipping-address element had a named complex type. 2 Another Road Unmarshal Demo When unmarshalling XML that corresponds to a class annotated with @XmlRootElement you get an instance of the domain object. But when unmarshalling XML that corresponds to a class annotated with @XmlElementDecl you get the domain object wrapped in an instance of JAXBElement. In this example you may need to use the QName from the JAXBElement to determine if you unmarshalled a billing or shipping address. package org.example.customer; import java.io.File; import javax.xml.bind.*; public class UnmarshalDemo { public static void main(String[] args) throws Exception { JAXBContext jc = JAXBContext.newInstance("org.example.customer"); Unmarshaller unmarshaller = jc.createUnmarshaller(); // Unmarshal Customer File customerXML = new File("src/org/example/customer/customer.xml"); Customer customer = (Customer) unmarshaller.unmarshal(customerXML); // Unmarshal Shipping Address File shippingXML = new File("src/org/example/customer/shipping.xml"); JAXBElement je = (JAXBElement) unmarshaller.unmarshal(shippingXML); AddressType shipping = je.getValue(); } } Unmarshal Demo - JAXBIntrospector If you don't want to deal with remembering whether the result of the unmarshal operation will be a domain object or JAXBElement, then you can use the JAXBIntrospector.getValue(Object) method to always get the domain object. package org.example.customer; import java.io.File; import javax.xml.bind.*; public class JAXBIntrospectorDemo { public static void main(String[] args) throws Exception { JAXBContext jc = JAXBContext.newInstance("org.example.customer"); Unmarshaller unmarshaller = jc.createUnmarshaller(); // Unmarshal Customer File customerXML = new File("src/org/example/customer/customer.xml"); Customer customer = (Customer) JAXBIntrospector.getValue(unmarshaller .unmarshal(customerXML)); // Unmarshal Shipping Address File shippingXML = new File("src/org/example/customer/shipping.xml"); AddressType shipping = (AddressType) JAXBIntrospector .getValue(unmarshaller.unmarshal(shippingXML)); } } Marshal Operation You can directly marshal an object annotated with @XmlRootElement to XML. Classes corresponding to @XmlElementDecl annotations must first be wrapped in an instance of JAXBElement. The factory method you you annotated with @XmlElementDecl is the easiest way to do this. The factory method is in the ObjectFactory class if you generated your model from an XML schema. package org.example.customer; import javax.xml.bind.*; public class MarshalDemo { public static void main(String[] args) throws Exception { JAXBContext jc = JAXBContext.newInstance("org.example.customer"); Marshaller marshaller = jc.createMarshaller(); marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); // Create Domain Objects AddressType billingAddress = new AddressType(); billingAddress.setStreet("1 Any Street"); Customer customer = new Customer(); customer.setBillingAddress(billingAddress); // Marshal Customer marshaller.marshal(customer, System.out); // Marshal Billing Address ObjectFactory objectFactory = new ObjectFactory(); JAXBElement je = objectFactory.createBillingAddress(billingAddress); marshaller.marshal(je, System.out); } } Output Below is the output from running the demo code. 1 Any Street 1 Any Street

ever wondering what could be a keyboard shortcut for something in eclipse? in my post on 10 best eclipse shortcuts the question came up how to traverse through all the open files in the editor. finding a shortcut is easy if you know the the mother of all eclipse shortcuts . i press ctrl+3 and enter a search term like ‘switch’, and it shows me all shortcuts with ‘switch’ in the description: ctrl plus 3 shows all shortcuts so with this i know that ctrl+tab is to switch to the next editor. let’s try it out: ctrl+tab popup window a small pop-up window shows all open sources of the editor view: pressing ctrl+tab repeatedly will iterate through the source files. that way i can quickly switch to another source file without leaving my fingers from the keyboard. happy switching

Measuring similarity or distance between two data points is fundamental to many Machine Learning algorithms such as K-Nearest-Neighbor, Clustering ... etc.

Generate a random alpha numeric string whose length is the number of characters specified. Characters will be chosen from the set of alpha-numeric characters. Count is the length of random string to create. private static final String ALPHA_NUMERIC_STRING = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; public static String randomAlphaNumeric(int count) { StringBuilder builder = new StringBuilder(); while (count-- != 0) { int character = (int)(Math.random()*ALPHA_NUMERIC_STRING.length()); builder.append(ALPHA_NUMERIC_STRING.charAt(character)); } return builder.toString(); }

From theses to reports and books, LaTeX is a pretty useful document markup language. Learn how to install the Tex Live distribution here.

This article is based on my answer on StackOverflow. I am trying to explain how String class stores the texts, how interning and constant pool works. The main point to understand here is the distinction between String Java object and its contents - char[] under private value field. String is basically a wrapper around char[] array, encapsulating it and making it impossible to modify so the String can remain immutable. Also the String class remembers which parts of this array is actually used (see below). This all means that you can have two different String objects (quite lightweight) pointing to the same char[]. I will show you few examples, together with hashCode() of each String and hashCode() of internal char[] value field (I will call it text to distinguish it from string). Finally I'll show javap -c -verbose output, together with constant pool for my test class. Please do not confuse class constant pool with string literal pool. They are not quite the same. See also Understanding javap's output for the Constant Pool Prerequisites For the purpose of testing I created such a utility method that breaks String encapsulation: private int showInternalCharArrayHashCode(String s) { final Field value = String.class.getDeclaredField("value"); value.setAccessible(true); return value.get(s).hashCode(); } It will print hashCode() of char[] value, effectively helping us understand whether this particular String points to the same char[] text or not. Two string literals in a class Let's start from the simplest example. Java code String one = "abc"; String two = "abc"; BTW if you simply write "ab" + "c", Java compiler will perform concatenation at compile time and the generated code will be exactly the same. This only works if all strings are known at compile time. Class constant pool Each class has its own constant pool - a list of constant values that can be reused if they occur several times in the source code. It includes common strings, numbers, method names, etc. Here are the contents of the constant pool in our example above: const #2 = String #38; // abc //... const #38 = Asciz abc; The important thing to note is the distinction between String constant object (#2) and Unicode encoded text "abc" (#38) that the string points to. Byte code Here is generated byte code. Note that both one and two references are assigned with the same #2 constant pointing to "abc" string: ldc #2; //String abc astore_1 //one ldc #2; //String abc astore_2 //two Output For each example I am printing the following values: System.out.println("one.value: " + showInternalCharArrayHashCode(one)); System.out.println("two.value: " + showInternalCharArrayHashCode(two)); System.out.println("one" + System.identityHashCode(one)); System.out.println("two" + System.identityHashCode(two)); No surprise that both pairs are equal: one.value: 23583040 two.value: 23583040 one: 8918249 two: 8918249 Which means that not only both objects point to the same char[] (the same text underneath) so equals() test will pass. But even more, one and two are the exact same references! So one == two is true as well. Obviously if one and two point to the same object then one.value and two.value must be equal. Literal and new String() Java code Now the example we all waited for - one string literal and one new String using the same literal. How will this work? String one = "abc"; String two = new String("abc"); The fact that "abc" constant is used two times in the source code should give you some hint... Class constant pool Same as above. Byte code ldc #2; //String abc astore_1 //one new #3; //class java/lang/String dup ldc #2; //String abc invokespecial #4; //Method java/lang/String."":(Ljava/lang/String;)V astore_2 //two Look carefully! The first object is created the same way as above, no surprise. It just takes a constant reference to already created String (#2) from the constant pool. However the second object is created via normal constructor call. But! The first String is passed as an argument. This can be decompiled to: String two = new String(one); Output The output is a bit surprising. The second pair, representing references to String object is understandable - we created two String objects - one was created for us in the constant pool and the second one was created manually for two. But why, on earth the first pair suggests that both String objects point to the same char[] value array?! one.value: 41771 two.value: 41771 one: 8388097 two: 16585653 It becomes clear when you look at how String(String) constructor works (greatly simplified here): public String(String original) { this.offset = original.offset; this.count = original.count; this.value = original.value; } See? When you are creating new String object based on existing one, it reuses char[] value. Strings are immutable, there is no need to copy data structure that is known to be never modified. Moreover, since new String(someString) creates an exact copy of existing string and strings are immutable, there is clearly no reason for the two to exist at the same time. I think this is the clue of some misunderstandings: even if you have two String objects, they might still point to the same contents. And as you can see the String object itself is quite small. Runtime modification and intern() Java code Let's say you initially used two different strings but after some modifications they are all the same: String one = "abc"; String two = "?abc".substring(1); //also two = "abc" The Java compiler (at least mine) is not clever enough to perform such operation at compile time, have a look: Class constant pool Suddenly we ended up with two constant strings pointing to two different constant texts: const #2 = String #44; // abc const #3 = String #45; // ?abc const #44 = Asciz abc; const #45 = Asciz ?abc; Byte Code ldc #2; //String abc astore_1 //one ldc #3; //String ?abc iconst_1 invokevirtual #4; //Method String.substring:(I)Ljava/lang/String; astore_2 //two The fist string is constructed as usual. The second is created by first loading the constant "?abc" string and then calling substring(1) on it. Output No surprise here - we have two different strings, pointing to two different char[] texts in memory: one.value: 27379847 two.value: 7615385 one: 8388097 two: 16585653 Well, the texts aren't really different, equals() method will still yield true. We have two unnecessary copies of the same text. Now we should run two exercises. First, try running: two = two.intern(); before printing hash codes. Not only both one and two point to the same text, but they are the same reference! one.value: 11108810 two.value: 11108810 one: 15184449 two: 15184449 This means both one.equals(two) and one == two tests will pass. Also we saved some memory because "abc" text appears only once in memory (the second copy will be garbage collected). The second exercise is slightly different, check out this: String one = "abc"; String two = "abc".substring(1); Obviously one and two are two different objects, pointing to two different texts. But how come the output suggests that they both point to the same char[] array?!? one.value: 23583040two.value: 23583040one: 11108810two: 8918249 I'll leave the answer to you. It'll teach you how substring() works, what are the advantages of such approach and when it can lead to big troubles. Lessons learnt String object itself is rather cheap. It's the text it points to that consumes most of the memory String is just a thin wrapper around char[] to preserve immutability new String("abc") isn't really that expensive as the internal text representation is reused. But still avoid such construct. When String is concatenated from constant values known at compile time, concatenation is done by the compiler, not by the JVM substring() is tricky, but most importantly, it is very cheap, both in terms of used memory and run time (constant in both cases)

In a previous post I wrote how to install Apache thrift on Windows. In this post I will guide you how to install Apache Thrift on Ubuntu 12.04. Install dependencies using the following command sudo apt-get install libboost-dev libboost-test-dev libboost-program-options-dev libevent-dev automake libtool flex bison pkg-config g++ libssl-dev Download tar.gz archive from the this link, extract it in your home directory using this command tar -xvzf thrift-0.8.0.tar.gz Change into the Thrift installation directory(the one extracted) and carry on the following command ./configure Run the following command within Thrift installation directory make After that carry on the following command sudo make install To verify Thrift has installed properly, use the following command thrift -version