PHP实现的观察者模式实例

yuchao

            本文实例讲述了PHP实现的观察者模式。分享给大家供大家参考，具体如下：
_observers[] = $sub;
    }
    //外部统一调用
    public function trigger(){
      if(!empty($this->_observers)){
        foreach($this->_observers as $observer){
          $observer->update();
        }
      }
    }
  }
  //观察者接口
  interface obserable{
    public function update();
  }
  //实现观察者
  class listen implements obserable{
    public function update(){
      echo 'now first time you need to do listen
';
    }
  }
  class read implements obserable{
    public function update(){
      echo 'now first time you need to read
';
    }
  }
  class speak implements obserable{
    public function update(){
      echo 'now first time you need to speak
';
    }
  }
  class write implements obserable{
    public function update(){
      echo 'now first time you need to write
';
    }
  }
  $transfer = new transfer();
  $transfer->register(new listen());
  $transfer->register(new read());
  $transfer->register(new speak());
  $transfer->register(new write());
  $transfer->trigger();