observers[] = $observer;		}		function  notify(){			foreach($this->observers as $observer){				$observer->update();			}		}	}	interface Observer{		function update($event_info = NULL);	}	class Observer1 implements Observer{		function update($event_info = NULL)		{			// TODO: Implement update() method.			echo '观察者1
';		}	}	class Observer2 implements Observer{		function update($event_info = NULL)		{			// TODO: Implement update() method.			echo "观察者2
";		}	}	class Event extends EventGenerator{		function trigger(){			echo "Event
\n";			$this->notify();			逻辑1			//echo "逻辑1
";			逻辑3			//echo "逻辑2
";			逻辑3			//echo "逻辑3
";		}	}	$event = new Event();	$event->addObserver(new Observer1());	$event->addObserver(new Observer2());	$event->trigger();