public void addPropertyChangeListener(PropertyChangeListener l){
  if (listeners == null) {
    listeners=new ArrayList<PropertyChangeListener>(2);
  }
  if (!listeners.contains(l)) {
    listeners.add(l);
  }
}

public void addPropertyChangeListener ( PropertyChangeListener l ) { if ( listeners == null ) { listeners = new ArrayList < PropertyChangeListener > ( 2 ) ; } if ( ! listeners . contains ( l ) ) { listeners . add ( l ) ; } }
add an addresslistener . addresslisteners are notified when the user selects a new address and when a throttle is acquired for that address
