code: protected void notifyChatterObservers ()
      {
          _chatterObservers.apply(new ObserverList.ObserverOp<ChatterObserver>() {
              public boolean apply (ChatterObserver observer) {
                  observer.chattersUpdated(_chatters.listIterator());
                  return true;
              }
          });
      }
docs: Notifies all registered {@link ChatterObserver}s that the list of chatters has changed.