/*
  * (non-Javadoc)
  *
  * @see
  * org.gwt.beansbinding.ui.client.adapters.BeanAdapterBase#listeningStarted
  * ()
  */
 @Override
 protected void listeningStarted() {
   handler = new Handler();
   cachedString = getValue();
   registration = radioButtonGroup.addValueChangeHandler(handler);
 }