SubscriberRegistry.java 文件源码

/**
 * Unregisters all subscribers on the given listener object.
 */
void unregister(Object listener) {
  Multimap<Class<?>, Subscriber> listenerMethods = findAllSubscribers(listener);

  for (Map.Entry<Class<?>, Collection<Subscriber>> entry : listenerMethods.asMap().entrySet()) {
    Class<?> eventType = entry.getKey();
    Collection<Subscriber> listenerMethodsForType = entry.getValue();

    CopyOnWriteArraySet<Subscriber> currentSubscribers = subscribers.get(eventType);
    if (currentSubscribers == null || !currentSubscribers.removeAll(listenerMethodsForType)) {
      // if removeAll returns true, all we really know is that at least one subscriber was
      // removed... however, barring something very strange we can assume that if at least one
      // subscriber was removed, all subscribers on listener for that event type were... after
      // all, the definition of subscribers on a particular class is totally static
      throw new IllegalArgumentException(
          "missing event subscriber for an annotated method. Is " + listener + " registered?");
    }

    // don't try to remove the set if it's empty; that can't be done safely without a lock
    // anyway, if the set is empty it'll just be wrapping an array of length 0
  }
}