Developing Plugins

This page details how to create a new plug-in in order to extend the GAML language with new skills, species, displays or operators. It also details how to create a plug-in that can be uploaded on an update site and can be installed into the GAMA release. We consider here that the developer version of GAMA has been installed (as detailled in this page).

I. Creation of a plug-in

Here are detailed steps to create and configure a new GAMA plug-in.

1. From the Eclipse main menu tab, click on File, then New, then Project, then finally select plug-in project.

2. In the New plug-in Project/Plug-in project window:

   1. Choose as name the name of your plugin
   2. Check Use default location
   3. Check Create a Java Project
   4. The project should be targeted to run with Eclipse
   5. working set is unchecked
   6. Click on Next

   

3. In the New plug-in Project/Content window:

   1. ID: could contain the name of your institution and/or your project, e.g. irit.maelia.gaml.additions
   2. Version: 1.0.0.qualifier (this latter mention is important if you plan on distributing the plugin on GAMA update site)
   3. Name: a concise description of the plugin
   4. Uncheck Generate an activator, a Java class that controls the plug-in's life cycle.
   5. Uncheck This plug-in will make contributions to the UI
   6. Check No when it asks if you would like to create a rich client application?
   7. Click on Next

   

4. In the New plug-in Project/Templates window:

   1. Uncheck Create a plug-in using a template
   2. Click on Finish

   

   3. Your plug-in has been created.

5. Edit the file Manifest.MF:

   1. From the Project Explorer pane, expand your plugin folder.
   2. Click on the META-INF folder.
   3. Click on the MANIFEST.MF file.

   

   4. Click on the Overview tab to open the Overview pane:

   5. Check as shown This plug-in is a singleton

   6. Dependencies pane:

      1. Click on the Dependencies.

      

      2. add (at least) the two plug-ins gama.core and gama.dependencies in the Required Plug-ins. When you click on Add, a new window will appear without any plug-in. Just write the beginning of the plug-in name in the text field under Select a plug-in

      

   7. Click on the Runtime tab to open the Runtime pane:

      

      1. In Exported Packages: nothing (but when you will have implemented new packages in the plug-in you should add them there)
      2. Add in the Classpath all the additional libraries (.jar files) used in the project.

   8. Click on the Extensions tab to open the Extensions pane:

      • Click the Add... button and add gaml.extension

   

6. On the main menu, click on File, then select Save, to save the file. This should create a plugin.xml file.

7. In the Project Explorer view, select the plugin, right click on it, and in the contextual menu select Properties:

   

   1. The Properties dialog for your plugin opens as shown.

   

   2. In the Properties dialog, go to Java Compiler, then Annotation Processing: check Enable project specific settings, then in Generated Source Directory, change .apt\_generated to gaml,

   

   3. Go again to Java Compiler, then Annotation Processing, then Factory path: check Enable project specific settings, then Add Jars and choose gama.processor/gama.processor.jar

   

   4. Close the menu. Click on Yes in the succeeding dialogs (Annotation settings changed ...). After, this should compile the project and create the gaml directory.

   

8. Return to the Properties dialog of your plugin by clicking from the main menu bar, Project, then click on Properties. Go to Java Build Path, click on the Source Tab, and check that the gaml directory has been added.

9. If the gaml folder is not present, click on Add Folder... and select the gaml directory. Right click on the project, then refresh it (F5 or from the File menu -> Refresh)

10. Now, there should be a gaml directory. This gaml directory will later contain the package containing GamlAdditions.java, and other related files generated after creating classes. If there is no package in the folder, try creating a class, then try to refresh or close the project and reopen it, or clean the projects by going into Project tabs, and clicking on clean.

The plug-in is ready to accept any addition to the GAML language, e.g. skills, actions, operators. To proceed to creating a skill click on this link.

Do not forget to export the created packages that could be used by "clients", especially the packages containing the code of the additions (in the plugin.xml of the new project, tab Runtime).

To test the plug-in and use it into GAMA, developers have to define a new feature project containing your plugin and its dependencies, and add this feature to the existing gama.product file (or a new .product file of your own).

The use of feature project is also mandatory to define a plug-in that can be uploaded on the update site and can be installed in the release of GAMA.

Creation of a feature

A feature is an Eclipse project dedicated to gathering one or several plug-ins to integrate them into a product or to deploy them on the update site and install them from the GAMA release (a feature is mandatory in this case).

Here are detailed steps to create and configure a new feature.

• File > New > Feature project (or File > New > Project... then Plug-in Development > Feature Project)
• In Feature properties
  • Choose a project name (e.g. institution.gama.feature.pluginsName)
  • Click on Next
• In Referenced Plug-ins and fragments
  • Check Initialize from the plug-ins list:
  • Choose the plug-ins that have to be gathered in the feature
  • Click on Finish
• A new project has been created. The feature.xml file will configure the feature.
  • In Information pane:
    • You can add description of the various plug-ins of the feature, define the copyright notice and the licence.
  • In Plug-ins and Fragments
    • additional plug-ins can be added.

Addition of a feature to the product

To load the plugin into GAMA, go into the project gama.product open the gama.product file and go into the overview tab, under the section Testing, click Synchronize, go into the Contents tab, click on Add..., and add the features related to your plugin. Click the Run tab in the main menu bar, click on Run Configurations..., then you should have the gama runtime product window open, click on the Plug-ins tab, and check the box next to your plugin in the list. Click on Apply. Now that your plugin is accessible in GAMA, we can run the application. Click on Run.

Remark: To check whether the new plug-in has been taken into account by GAMA, after GAMA launch, it should appear in the Eclipse console in a line beginning by >> GAMA bundle loaded in .

If you plan to deploy your plugin to be used by other users from the GAMA community, proceed with the succeeding steps. If not, we can proceed with the creation of skills and types.

In the product, e.g. gama.product in the gama.product project:

• go to Contents pane
  • Click on Add... button
  • In the window select the feature
  • Click on OK.

Create examples model

In order to make your plugin usable by everyone, it is very important to bring potential users model examples to introduce new gaml primitives, statements and operators. This way, modelers can easily get into the plugin you developed in a practical way.

The process is twofold:

• Mount your plugin into your GAMA (see below or use the git version)
• Create a new project in the user model folder. Put your GAMA model examples there.
• Move your project into a folder called models at the root of the plugin

Once this is done, you can refresh your Plugin models library folder and have access to the plugin models

How to make a plug-in available at GAMA update site for the GAMA release

Considering a working GAMA plugin named institution.gama.pluginsName

Configure plugin to be available for Maven

Add pom.xml for plugin institution.gama.pluginsName:

• Right click on the project-> Configure -> Convert to maven project.
• In the dialog that opened, set the values as this:
  • Group id: institution.gama.pluginsName
  • Artifact id: institution.gama.pluginsName
  • Version: 1.0.0-SNAPSHOT, must have -SNAPSHOT if the plugin version is x.x.x.qualifier
  • Packaging: eclipse-plugin. This element is not in the list (jar/pom/war) because of the incompatible of tycho, maven and eclipse, so just type it in although it will be a warning
• Finish

Configure pom.xml to recognize the parent pom.xml for Maven builds

• Open pom.xml in institution.gama.pluginsName
• In the tab Overview, Parent section, type in:
  • Group id: org.gama
  • Artifact id: gama.experimental.parent
  • Version: 2024-07-SNAPSHOT replace by the gama version you want your plugin to be deployed for, followed by -SNAPSHOT
  • Relative path: ../gama.experimental.parent
• Save

Update maven cache in eclipse (optional)

It will fix this compilation error Project configuration is not up-to-date with pom.xml. Right click on the project and in the contextual menu select: Maven->Update Project... or use Quick Fix.

Create a feature for the plugin

Create new feature

• New -> Project -> type in : feature -> Select Feature Project
• Set:
  • Project name: institution.gama.feature.pluginsName
  • Uncheck use default location, type in: {current git repository}\institution.gama.feature.pluginsName
  • Feature Version: 1.0.0.qualifier
• Click Next
  • Initialize from the plugin list -> check all plugins needed: institution.gama.pluginsName (1.0.0.qualifier)
• Finish
• Open feature.xml, in the tab Overview, in the General Information section type in:
  • Update Site URL: http://updates.gama-platform.org/experimental
  • Update Site Name: GAMA Experimental Plugins Update Site

Add pom.xml for feature institution.gama.feature.pluginsName:

• Right click on the feature project -> Configure -> Convert to maven project
• Set:
  • Group id: institution.gama.feature.pluginsName
  • Artifact id: institution.gama.feature.pluginsName
  • Version: 1.0.0-SNAPSHOT
  • Packaging: eclipse-feature
• Finish

Configure pom.xml to recognize the parent pom.xml for Maven builds

• Open pom.xml in the project institution.gama.pluginsName
• In the Overview section in the tab Parent type in:
  • Group id: org.gama
  • Artifact id: gama.experimental.parent
  • Version: 2024-07-SNAPSHOT replace by the gama version you want your plugin to be deployed for, followed by -SNAPSHOT
  • Relative path: ../gama.experimental.parent
• Save

Update maven cache in eclipse (optional)

It will fix this compilation error Project configuration is not up-to-date with pom.xml. Select: Maven->Update Project... from the project contextual menu or use Quick Fix.

Update p2updatesite

• Open gama.experimental.p2updatesite
• Tab Managing the Categories -> Add feature -> institution.gama.feature.pluginsName