1. Compilation of the complete GEMOC Studio

1.1. Introduction

The source code of the [GEMOC Studio]( is currently spread among different git repositories in Eclipse organization.

This project relies on the presence of the correct git repositories (cloned with the correct name) to locally build a working studio.

1.2. Usage

First checkout the git repositories :

git clone
git clone

Note: the repositories must keep their names (Ie. do not change the destination folder name) as the maven pom file expects to find them at specific locations.

Then compile using maven:

cd gemoc-studio/dev_support/full_compilation
mvn package -Dmaven.repo.local=$PWD/localm2

We use one options:

  • -Dmaven.repo.local=$PWD/localm2: use a folder called localm2 to cache all the external dependencies of the studio, instead of using the user local maven repository. Since the GEMOC Studio a full eclipse package and has around 1GB of dependencies, this avoids using this much space in a hidden folder of the user home dir.

If you prefer to use your own local maven repository (ie. in <HOME>/.m2/repository), remove the use of -Dmaven.repo.local, ie. use this command:

mvn package

If you already compiled and resolved all dependencies at least once (ie. if you filled your local maven repository with everything needed for the build), add the option -o to perform an offline only build, which is significantly faster since it skips checking all maven repositories online.

In the end, the result can be found in gemoc_studio/gemoc_studio/releng/org.eclipse.gemoc.gemoc_studio.product/target/products/, with one studio zip per platform.

The build also assemble complementary results:

  • an update site, available in gemoc_studio/gemoc_studio/releng/org.eclipse.gemoc.gemoc_studio.product/target/repository/
  • an archivable version of the web help; available in gemoc-studio/docs/

2. Developing new features

2.1. Developing new Addons


GEMOC addons mecanism is the simpliest way to contribute new features to GEMOC. Most of the features in GEMOC have been developed using it.

Basically, it uses Eclipse plugin extension point in order to provide additional feature to an existing engine.

The main extension point is org.eclipse.gemoc.gemoc_language_workbench.engine_addon which allows to declare a new class that implements the IEngineAddon interface.

Minimal steps to get an addons:

  • Create a plugin project (or contribute to an existing one)
  • In the MANIFEST.MF or plugin.xml editor, open the extensions tab, Add, uncheck "Show only extension from the required plugins", search for "gemoc" and select the org.eclipse.gemoc.gemoc_language_workbench.engine_addon extension point, accept to add the dependency to the plugin. (see Figure 34, “New Extension forEngine Addon screenshot”)
  • add an addon entry in the extension point (see Figure 35, “EngineAddon extension point details screenshot”) provide a name and a description that will help the end user to know if she wish to enable the addon or not in the launch tab when configuring her model execution.
  • Create the class implementing org.eclipse.gemoc.xdsmlframework.api.engine_addon.IEngineAddon (a click on Class*: in the extension editor allows to open a wizard that simplify this task)
  • you can now override any of the default methods of the interface (cf. Figure 31, “Execution Framework API Interfaces overview”). If the user select the addon in the launch tab, these methods will be called by the engine.
New Extension forEngine Addon screenshot

Figure 34. New Extension forEngine Addon screenshot

EngineAddon extension point details screenshot

Figure 35. EngineAddon extension point details screenshot


The calls from the engine to the methods of IEngineAddons block the model execution. Thus, except if this is the expected behavior, the addons should avoid to do complex/long running/blocking task directly in the


For a given notification to IEngineAddon (for example aboutToExecuteStep), the order of calls to all registered addons is currently not ensured.

Help is welcome in order to implement a way to specify partial order between addons as it might be useful when several collaborating addons must react on the same notification.


In the extension declaration, setting Default to true will activate the addon by default when creating a new launch configuration. The user is still able to disable the addon manually.


See Section 2, “GEMOC Framework” for more details about the extension point and other supported features.

2.2. Developing new engines


As seen in Figure 28, “Components overview”, the framework is organized in several layers. The most complete layer is the GEMOC Framework which offers most of the advanced features. Thus, implementing an engine for a new technology consist in 2 main parts:

  • implementing subclasses for the classes from XDSML Framework in order to have the part dedicated to the Language Workbench,
  • and implementing subclasses for the classes from Execution Framework in order to have the part dedicated to the Modeling Workbench

3. Distributing new features

TODO add info about how to distribute contribution and new features

4. Documentation


The GEMOC documentation (this document) structure is designed to:

  • allow both online and eclipse help output,
  • display an outline that helps organizing contributions,
  • maintain the documentation sources as close as possible of the documented element in order to associate documentation commits to the code commits,
  • use a rich but human readable syntax,
  • ease modification.

As it supports include directives, we chose Asciidoc syntax with the appropriate tool chain.

Some of the diagrams are generated using plantuml.

The document is organized as follow:


In order to ease modifications, every files must start with a footnote allowing to retrieve the source file in the git repositories.


To edit the documentation we recommand the use of plantuml eclipse plugin and eclipse asciidoc editor . You can install them in an Eclipse using either the market place or the following update site: