Steve's Blog

	// this listener deals with handling changes to markers.
	private static IResourceChangeListener markerListener =  new IResourceChangeListener() {
				private MarkerChangeVisitor fVisitor = new MarkerChangeVisitor();

				public void resourceChanged(IResourceChangeEvent event) {
		           IResourceDelta delta= event.getDelta();
		           if (delta != null)
		           {
		                try {
		                    delta.accept(fVisitor);
		                } catch (CoreException ce) {

		                }
				   }
				   }
		   };

/**
 * This class deals with navigating the IResourceDelta to locate changes in markers
 * i.e. whether they are added, changed or deleted.
 *
 * @author Stephen Cummins, Durham University, (c) 12 Aug 2009
 */
public class MarkerChangeVisitor implements IResourceDeltaVisitor
{
	   /**
	    * The method to be called for each visited delta.
	    * @return a boolean value
	    */
	   public boolean visit(IResourceDelta delta) throws CoreException
	   {
		   if(delta == null)
			   	return false;

		   IMarkerDelta[] markerDeltas = delta.getMarkerDeltas();

		   for (int i= 0; i < markerDeltas.length; i++) {
			   IMarkerDelta markerDelta= markerDeltas[i];
			   if (markerDelta.isSubtypeOf(IMarker.BOOKMARK)) {
				   switch (markerDelta.getKind()) {
				   case IResourceDelta.ADDED :
					   // Could do something here
					   break;
				   case IResourceDelta.REMOVED :
					   //Do something here
					   break;
				   case IResourceDelta.CHANGED:
					   // Could do something here
					   break;
				   }
			   }
		   }
		   return true;
	   }
}

	/**
	 * startMarkerListener
	 * This method will add the MarkerListener to the workspace to alert the plugin when a marker is changed
	 * 
	 */
	public static void startMarkerListener() {
		IWorkspace workspace = ResourcesPlugin.getWorkspace();		
		workspace.addResourceChangeListener(markerListener);
	}
	
	/**
	 * shutdownMarkerListener
	 * This method will cause the plugin to stop being notified about marker changes.
	 */
	public static void shutdownMarkerListener(){
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		workspace.removeResourceChangeListener(markerListener);
	}