protected void notifyDelete(Resource.Type type, Predicate predicate) {
    updateObservers(new ResourceProviderEvent(type, ResourceProviderEvent.Type.Delete, null, predicate));
  }
Notify all listeners of a delete event.

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