PHPオブザーバモードの実装コード

コードは次のとおりです.

 
  
//       
  
class Observed implements SplSubject{ 
  
    protected $_name; 
  
    protected $_observers; 
   
  
    //   ,         
    public function __construct(){
        $this->_observers = new SplObjectStorage();
    }
 
  
    //        
    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){
            $observer->showMessage($this);
        }
    }
 
  
    //    :    
    public function setName($name){
        $this->_name = $name;
        $this->notify();
    }
 
  
    //    :    
    public function getName(){
        return $this->_name;
    }
 
  
    //    :    
    public function setAge($age){
        $this->age = $age;
        foreach($this->_observers as $observer){
            $observer->showAge($this->_name,$this->age);
        }
    }
 
  
}
 
  
//       
class Observer implements SplObserver{
 
  
    //      
    public function showMessage(SplSubject $obj){
        $user = $obj->getName();
        if($user==='admin'){
            echo '  , ',$user,'         
';
        }else{
            echo "  , '$user'             
";
        }
    }
    //           
    public function update(SplSubject $subject) {}
 
  
    //      
    public function showAge($name,$age){
        echo "alert('$name     : $age')";
    }
}
 
  
$subject = new Observed();  //          
$observer = new Observer(); //         
$subject->attach($observer);//            
$subject->setName('  '); //   setName   
/*
 *      setName       $this->notify();
*       $this->notify()     $observer->showMessage($this)  ,
*           showMessage($obj)  ;
*/
$subject->setName('admin');
$subject->setAge(24);