//SplObserver 是系統內建的 觀察者介面；
class MyObserver1 implements SplObserver {
    //SplSubject 是系統內建的事件發生者介面
public function update(SplSubject $subject) {
        echo __CLASS__ . ' - ' . $subject->getName();
    }
}

class MyObserver2 implements SplObserver {
    public function update(SplSubject $subject) {
        echo 
 
__CLASS__ . ' - ' . $subject->getName();
    }
}
//SplSubject系統內建的事件發生者
class MySubject implements SplSubject {
    private $_observers;
    private $_name;

    public function __construct($name) {
        //必須這麼寫
$this->_observers = new SplObjectStorage();

        $this->_name = $name;
    }

    public function 
 
attach(SplObserver $observer) {
        $this->_observers->attach($observer);
    }

    public function detach(SplObserver $observer) {
        $this->_observers->detach($observer);
    }

    public function notify() {
        foreach ($this->_observers as $observer) {
            $observer
 
->update($this);
        }
    }

    public function getName() {
        return $this->_name;
    }
}

$observer1 = new MyObserver1();
$observer2 = new MyObserver2();

$subject = new MySubject("test");

$subject->attach($observer1);
$subject->attach($observer2);
$subject->notify();