Eclipse4/RCP/Modeled UI/Contributing to the Model

Model Fragments

Your application model can be spread out across several e4xmi files, to be stiched together at startup. This mechanism allows adding new mode elements or referencing existing model elements to collections defined by other model elements. For example, you can use a fragment to define a new MWindow and add it to the MApplication's children (a set of windows). It is important that any model elements that you intend to reference have a unique elementId (e.g., the MApplication).

1. Create a fragment file, typically called fragment.e4xmi
2. Add the necessary imports to bring in model elements that will be referenced, as opposed to being extended
3. Add StringModelFragments for each of the model elements to be extended. The parentElementId is the elementId of the element to be extended. featureame is the container feature name where new or existing elements will be added to.

For example, the following is a very simplified example of a fragment adding a command handler for the standard Exit/Quit command, where the command was defined elsewhere and thus imported:

<fragment:ModelFragments ...elided...>
  <imports xsi:type="commands:Command" xmi:id="XXXX" elementId="org.eclipse.ui.file.exit"/>
  <fragments xsi:type="fragment:StringModelFragment" xmi:id="..." featurename="handlers" parentElementId="my.e4.application">
    <elements xsi:type="commands:Handler" xmi:id="..." elementId="handler.exit"
       contributionURI="platform:/plugin/bundle/class.to.MyExitHandler" command="XXXX"/>
   </fragments>
</fragment:ModelFragments>

Finally, the fragment is then made available through the org.eclipse.e4.workbench.model extension point.

Creating Model Elements at Runtime

New elements are created and incorporated into the model using standard EMF patterns:

1. Obtain the appropriate factory for the package.
2. Create the desired object.
3. Incorporate it into the model, typically by adding it to the appropriate container, to cause the element to be rendered.

For example, to create a new part:

// the container will hold the new element; maybe obtained using the EModelService
MPartStack container = ...; 
MPart part = MBasicFactory.INSTANCE.createPart();
part.setLabel("The Part Label");
part.setElementId("a-unique-identifier-for-this-part");
part.getPersistedState().put("input", "http://eclipse.org");
part.setContributionURI("platform:/plugin/bundle/classname");
 
container.getChildren().add(part);
container.setSelectedElement(part);  // raise to top