code: public synchronized void setSelector(Selector v)
     {
        if (selector != null && selector instanceof NotificationListener)
        {
           listeners.remove((NotificationListener)selector);
        }
  
        selector = v;
  
        if (selector != null && selector instanceof NotificationListener)
        {
           listeners.add((NotificationListener)selector);
        }
     }
docs: {@inheritDoc}