code: @Override
      public void notifyChanged() {
          if (getNotification() && getListenerCount() > 0) {
              List<IChemObjectListener> listeners = lazyChemObjectListeners();
              for (Object listener : listeners) {
                  ((IChemObjectListener) listener).stateChanged(new QueryChemObjectChangeEvent(this));
              }
          }
      }
docs: This should be triggered by an method that changes the content of an object
  to that the registered listeners can react to it.