private void fireEvent(Event event, String viewName) {
    Set<Listener> listeners = this.listeners.get(viewName);

    if (listeners != null) {
      for (Listener listener : listeners) {
        listener.notify(event);
      }
    }
  }
Sync given view with data in DB. Ensures that view data in DB is updated,
all instances changes from xml config are reflected to DB

@param view                view config from xml
@param instanceDefinitions view instances from xml
@throws Exception if the view can not be synced
ambari-server/src/main/java/org/apache/ambari/server/view/ViewRegistry.java