@Override
  public void onConfigurationChanged() {
    super.onConfigurationChanged();

    // trigger getOutputColumns which will notify consumers in the case of
    // output changes
    if (isConfigured()) {
      getOutputColumns();
    }

    List<TransformerChangeListener> listeners = getAllListeners();
    for (TransformerChangeListener listener : listeners) {
      listener.onConfigurationChanged(this);
    }
  }