PHP觀察者模式的實現代碼

本文主要和大家介紹PHP實現的觀察者模式,結合具體執行個體形式分析了php觀察者模式的定義與使用方法,需要的朋友可以參考下，希望能協助到大家。

<?php  //定義觀察者調用介面  class transfer{    protected $_observers = array();    //註冊對象    public function register($sub){      $this->_observers[] = $sub;    }    //外部統一調用    public function trigger(){      if(!empty($this->_observers)){        foreach($this->_observers as $observer){          $observer->update();        }      }    }  }  //觀察者介面  interface obserable{    public function update();  }  //實現觀察者  class listen implements obserable{    public function update(){      echo 'now first time you need to do listen<br/>';    }  }  class read implements obserable{    public function update(){      echo 'now first time you need to read<br/>';    }  }  class speak implements obserable{    public function update(){      echo 'now first time you need to speak<br/>';    }  }  class write implements obserable{    public function update(){      echo 'now first time you need to write<br/>';    }  }  $transfer = new transfer();  $transfer->register(new listen());  $transfer->register(new read());  $transfer->register(new speak());  $transfer->register(new write());  $transfer->trigger();