protected void notifyUpdate(Resource.Type type, Request request, Predicate predicate) {
    updateObservers(new ResourceProviderEvent(type, ResourceProviderEvent.Type.Update, request, predicate));
  }
Notify all listeners of a update event.

@param type       the type of the resources being updated
@param request    the request used to update the resources
@param predicate  the predicate used to update the resources
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/AbstractResourceProvider.java