One of the objectives of Eclipse 4.0 was to make rich client development easier. One good example is the following use case: One view provides a selection (e.g. using a JFace TableViewer) and another view wants to get notified about a new selection of a domain object to get the chance to react on it.

First the selection provider part. The selection services can be easily injected using dependency injection.

@Inject
private ESelectionService selectionService;

When using a JFace viewer, the viewer selection has to be forwarded to the selction service:

tableViewer.addSelectionChangedListener(new ISelectionChangedListener() {
  @Override
  public void selectionChanged(SelectionChangedEvent event) {
    IStructuredSelection selection =
       (IStructuredSelection) event.getSelection();
    selectionService.setSelection(selection.getFirstElement());
  }
});

On the consumer side, the domain object is injected using an @Optional and @Named active selection. The following code snipped is part of a details view POJO that used es WritableValue (Eclipse data binding) to as holder for the actual domain object of type IContact.

@Inject
public void setSelection(
  @Optional @Named(IServiceConstants.ACTIVE_SELECTION) IContact contact) {
    if (contact != null) {
      contactValue.setValue(contact);
    }
}

That’s pretty convenient and concise compared with the code needed in Eclipse 3.x.

Have Fun!

Kai

From http://www.toedter.com/blog/?p=253