/**
 * This interface declares event notifiers. These entities can receive a
 * number of listeners, and notify events to them.
 * @author fpereira
 *
 */
public interface EventNotifier {
  /**
   * This method registers an event listener into the door.
   * @param listener the handler that will handle the triggering of the
   * clock.
   */
  void registerListener(Listener listener);

}