Use of RCP e3-plugins in pure e4-application

Question

I have an existing RCP-project that consists mostly of e3.x plugins. The target-platform is already migrated to Eclipse 4.5 and the compatibility layer is also in use. Currently it is possible to use the new POJO e4view in plugins. That "mixed mode" is working fine. But when I need to extend the existing menu via extensions (org.eclipse.ui.main.menu), I have to use the extension in plugin.xml. My goal is to create an application-model (Application.e4xmi) and migrate the definitions from the current main-plugin.xml to the new application-model (i.e. handler, menu definitions etc.). New plugins should use the new model-fragment (fragment.e4xmi). It is very important, that I wont modify the existing e3-plugins. Is it possible to migrate the existing main-plugin to pure e4 plugin and add the old e3-plugins without having to change them. The main goal is to write new e4-plugins (with DI, POJO handler, views etc.) while keeping the e3-plugins.

For example:

Plugin Main(e4): Application.e3xmi (contains menu definition, handler, commands etc.) plugin.xml (contains application and product target)

Plugin A(e4): e4views (POJO) fragment.e4xmi (contains extentions for new menu-entry) plugin.xml

Plugin B(legacy e3): e3 (extends from ViewPart) plugin.xml (contains extentions for new menu-entry, old handler)

Answer 1

I think at the moment there are only 2 ways to contribute to the application model.

1. Model Fragment
2. Model Processor

The second one would be an option for you to contribute your menu entries. The problem is afaik it's only possible with the new model elements and you would need to implement a processor in the e3 plug-ins. My conclusion is that a pure e4 application with e3 contributions is not possible right now but I could be wrong.

Example taken from: Eclipse4Modularity vogella

// the menu is injected based on the parameter
// defined in the extension point
@Inject
@Named("org.eclipse.ui.file.menu")
private MMenu menu;

---

MDirectMenuItem menuItem =  modelService.createModelElement(MDirectMenuItem.class);
menuItem.setLabel("Another Exit");
menuItem.setContributionURI("bundleclass://"
    + "com.example.e4.rcp.todo.contribute/"
    + ExitHandlerWithCheck.class.getName());
menu.getChildren().add(menuItem);