Difference between revisions of "Papyrus/Codegen/Adding a New Code Generator"

Revision as of 11:43, 4 November 2014

Papyrus has already have code generation support for C++ and Java programming languages. Besides, support for Ada and C programming languages are also on the way. However, it is possible to develop and integrate new code generators for other programming languages to Papyrus. In this article you will find how add a new code generator to Papyrus from scratch.

Preparing the Development Environment (Prerequisites)

This section provides a step-by-step guide to set up your development environment in order to be able to add a new code generator for Papyrus.

Assuming that you have already installed Papyrus, here are the steps you need to follow:

• Install the Qompass (Incubation) modeler extension from Help > Install Papyrus Additional Components.

• Clone the Eclipse/Papyrus git repository to your local computer.

Preparing the Required Projects

To be able to develop a new code generator for a programming language (let's say the X programming language), you need to create three different (but interrelated) projects.

• A main eclipse plug-in project for developing the code generator, which you should name it as org.eclipse.papyrus.x.codegen
• An eclipse plug-in project for connecting the code generator to the user interface of Qompass, which you should name it as org.eclipse.papyrus.x.codegen.ui
• Another eclipse plug-in project for developing the tests of the code generator, which you should name it as org.eclipse.papyrus.x.codegen.tests

Now, let's create and prepare all these projects one by one.

The Main Code Generation Project for the Hypothetical X Programming Language ("org.eclipse.papyrus.x.codegen")

Here are the steps for creating and setting the org.eclipse.papyrus.x.codegen project:

• Create an eclipse plug-in project. In the Project name box type org.eclipse.papyrus.x.codegen (as shown) and then click Next >.

• In the Version box type the version number of our target Papyrus (in our case to 1.0.1.qualifier), in the Name box type %pluginName, in the Vendor box type %providerName and then click Finish.

• Upon a successful project creation, you will switch to the Plug-in Development perspective and see an Eclipse workbench window like below.

• The project is created. Now, you need to do the required settings for integrating your project to Papyrus. Firstly, add a dependency to the org.eclipse.papyrus.codegen.extensionpoints extension point.

• Then add a new language support extension called org.eclipse.papyrus.codegen.extensionpoints.language.

• After, create a client for this extension as shown.

• And type in this client's language* box X, and in the class box type org.eclipse.papyrus.x.codegen.XLanguageSupport.

• Since you do not have such a class yet, you will see a warning like below.

• Double click on this warning. go to the warning icon on the opened editor and click Create org.eclipse.papyrus.x.codegen.XLanguageSupport ....

• On the upcoming dialog box, do not change anything and click Finish.

• Upon creation, you will see "XLanguageSupport.java" as below. To remove the errors, implement the methods coming from the ILangSupport interface.

• However, there will now be other errors due to the new dependencies.

• For importing the PackageableElement and Class classes, you need the org.eclipse.uml2.uml plug-in and, for importing the IProject interface, you need the org.eclipse.core.resources plug-in. Add them as dependencies as shown below.

• Now, there must be no problem in our project.

The User Interface Project ("org.eclipse.papyrus.x.codegen.ui")

Here are the steps for creating and setting the org.eclipse.papyrus.x.codegen.ui project:

• Create an eclipse plug-in project. In the Project name box type org.eclipse.papyrus.x.codegen.ui (as shown) and then click Next >.

• In the Version box type the version number of our target Papyrus (in your case to 1.0.1.qualifier), in the Name box type %pluginName, in the Vendor box type %providerName and then click Finish.

• Upon a successful project creation, you will switch to the Plug-in Development perspective and see a window like below.

• The project is created. Now, you need to do the required settings for integrating this user interface project to the main code generation project. Firstly, add a dependency to the org.eclipse.papyrus.x.codegen plug-in, in which you prepared in the previous step.

• Now you need to add some extensions for organizing your menus. Firstly, add org.eclipse.ui.menus.

• However, upon this addition, you may see a No schema found for the 'org.eclipse.ui.menus' extension point warning message as shown.

• In this case,install Eclipse RCP Target Components to your eclipse from The Eclipse Project Updates software site.

• After following the installation instructions and restarting your eclipse, things will be fine.

• Now add a menu contribution to the extension you added and...

• ...in the locationURI box type popup:org.eclipse.papyrus.views.modelexplorer.popup.codegen.

• Then create a command for this menu contribution and...

• ...in the commandID box type org.eclipse.papyrus.x.codegen.command, in the label and tooltip boxes type Generate X code.

• The second extension we need to add is "org.eclipse.ui.commands" and we need to create a command for it also, which has the following the properties: id as "org.eclipse.papyrus.x.codegen.command", name and description as "Generate X Code", categoryId as "org.eclipse.papyrus.editor.category" and defaultHandler as "org.eclipse.papyrus.x.codegen.ui.handlers.GenerateCodeHandler".

• Careful readers has already noticed that there is a warning occuring after this step (see the Problems tab on the above figure). The reason for this warning is that we defined a default handler that does not exist yet. By double-clicking to the warning, we go to source of the problem and simply fix it by creating our new handler class (keep default properties in the create class dialog window).

• The created handler class should extend the "CmdHandler" class which is located in the "org.eclipse.papyrus.acceleo.ui" plug-in. Thus, this plug-in should be added to the dependencies and then the unimplemented methods should be implemented. To see how this handler is executed, we added a system verbose inside its "execute()" method.

• The last extension we need to add is "org.eclipse.ui.preferencePages". Upon creation, it comes with a default page. We need to set the properties of this page as follows: id as "org.eclipse.papyrus.x.codegen.ui.preferences.CodeGenPreferencePage", name as "X code generation", class as "org.eclipse.papyrus.x.codegen.ui.preferences.CodegenPreferencePage" and category as "org.eclipse.papyrus.infra.core.sasheditor.preferences.generalcategory".

• However, like before, there is a warning occuring after this step (see the Problems tab on the above figure). The reason for this warning is that we defined a preference page that does not exist yet. By double-clicking to the warning, we go to source of the problem and simply fix it by creating our new preference page class (keep default properties in the create class dialog window).

• The created preference page class should extend the "PreferencePage" class and implement "IWorkbenchPreferencePage" interface. Normally, no modification is needed after the creation of our preference page class.

• Now let's try what we have done so far and see our code generation menu on a real case. In this sense, create an "Eclipse Application" run configuration using the menu "Run > Run Configurations..." and set the VM arguments as follows: "-Dosgi.requiredJavaVersion=1.7 -Xmn256m -Xms512m -Xmx512m -Xss4m -XX:PermSize=256m -XX:MaxPermSize=256m".

• Then click "Run" to run our eclipse application. In the new eclipse instance, go to "File > New > Example...", choose "C/C++ hello world example" under the "Papyrus examples" folder and click "Next >".

• After, we select a parent folder for our example and click "Finish". In our case, we have a "CodeGenerationExamples" java project that was created in advance.

• The example project will be created and the "HelloWorldOO.di" Papyrus model will be open directly. There is only one class diagram which is called "HelloWorld" as can be seen. Now, let's right click on the "HelloWorld" class and go to the "Code Generation" pop-up menu. We need to see our menu "Generate X code" there, click it! (Curious readers may click on "Generate C++ code" and see how Qompass generates C++ code)

• Clicking the "Generate X code" pop-up menu will cause our handler to execute and thus we need to see the system verbose we defined our handler class on the console of the main workbench.

If all the steps worked fine, we can go on by creating the test project of our code generator.

The Test Project ("org.eclipse.papyrus.x.codegen.tests")

Here are the steps for creating and setting the "org.eclipse.papyrus.x.codegen.tests" project:

Developing the New Code Generator

Integrating the New Code Generator to Papyrus