文档解释ORA-16820:fast-startfailoverobserverisnolongerobservingthisdatabaseCause:Apreviouslystartedobserverwasnolongeractivelyobservingthisdatabase.Asignificantamou...

    在CocoaTouch框架中，观察者模式的具体应用有两个——通知(notification)机制和KVO(Key-Value-Observing)机制。        ...