Time for action – dealing with events

There's a more generic way of passing information between components in Eclipse 4, using the OSGi EventAdmin service. This is a message bus, like JMS, but operates in memory. There is also an Eclipse-specific IEventBroker, which provides a slightly simpler API to send messages.

1. Add the following bundles as dependencies to the com.packtpub.e4.application project, by double-clicking on the project's META-INF/MANIFEST.MF file and going to the Dependencies tab:
   1. org.eclipse.osgi.services
   2. org.eclipse.e4.core.services
   3. org.eclipse.e4.core.di.extensions
2. Open the Rainbow class and inject an instance of IEventBroker into a private field broker:

   @Inject
   private IEventBroker broker;

3. Modify the selectionChanged method, so that instead of setting a selection, it uses the IEventBroker to post the color asynchronously to the rainbow/color topic:

   public void selectionChanged(SelectionChangedEvent event) {
     // selectionService.setSelection(event.getSelection...