code: private void fireStateChanged(Object node, State oldState, State newState)
      {
          for (StateListener stateListener : stateListeners)
          {
              stateListener.stateChanged(node, oldState, newState);
          }
      }
docs: Notify all {@link StateListener}s about a {@link State} change
  
  @param node The node whose state changed
  @param oldState The old state
  @param newState The new state