code: public boolean hasListeners(String propertyName) {
  		if (listeners != null && listeners.getListenerCount(PropertyChangeListener.class) > 0) {
  			// there is a generic listener
  			return true;
  		}
  		if (children != null) {
  			PropertyChangeSupport child = (PropertyChangeSupport) children.get(propertyName);
  			if (child != null) {
  				// The child will always have a listeners ArrayList.
  				return child.hasListeners(propertyName);
  			}
  		}
  		return false;
  	}
docs: Check if there are any listeners for a specific property.
  
  @param propertyName the property name.
  @return true if there are ore or more listeners for the given property