Graphical Modeling Framework Runtime - Eclipse Modeling Project: A Domain-Specific Language Toolkit - page 473

command that creates our domain element instance and passes it to the view
service. The view service uses our registered MindmapViewProvider and
obtains our TopicViewFactory based on the provided semanticHint.
For further clarification on how the runtime knows to create a new Topic
object and store it in the proper feature in our Map class, let's take a closer look
at the compound command that the creation tool uses and see how it works.
First, we need to cover our EditPart definition.

EditPart Definition
We must define our EditPart s for the diagram, which are provided by con-
tributing to the org.eclipse.gmf.runtime.diagram.ui.editpart
Providers extension-point. As with our view provider, we declare a provider
class that we need to implement.

<extension
point="org.eclipse.gmf.runtime.diagram.ui.editpartProviders">
<editpartProvider class=
"org.eclipse.mindmap.diagram.providers.MindmapEditPartProvider">
<Priority name="Lowest"/>
</editpartProvider>
</extension>

The implementation of our MindmapEditPartProvider is similar to that
of our ViewProvider , with a HashMap that contains our shape EditPart
classes keyed by their semanticHint , which is available from the passed View
using the getType() method. For now, we have only a single entry for our
Topic element. Our diagram EditPart is simply the default DiagramEdit
Part class that the runtime provides.

public class MindmapEditPartProvider extends AbstractEditPartProvider {

private final Map<String, Class<?>> diagramMap = new HashMap<String,
Class<?>>();

{

diagramMap.put(MindmapDiagramEditor.ID, DiagramEditPart. class );

}

private final Map<String, Class<?>> shapeMap = new HashMap<String,
Class<?>>();

{

shapeMap.put("Topic", TopicEditPart. class );

}

@Override
protected Class getDiagramEditPartClass(View view) {