PHP设计模式之中介者模式

    /**  
     * 测试用例描述：示例代码不仅允许乐队进入和管理他们的音乐合集，而且还允许乐队更新他们的配置文件，修改乐队相关信息以及更新其CD信息  
     *　　　　　　　 现在，艺术家可上传MP3集合并从Web站点撤下CD。 因此， Web站点需要保持相对应的CD和MP3彼此同步。  
     */   
    //CD类   
    class CD {   
           
        public $band  = '';   
        public $title = '';   
        protected $_mediator;   
           
        public function __construct(MusicContainerMediator $mediator = NULL) {   
            $this->_mediator = $mediator;   
        }   
           
        public function save() {   
            //具体实现待定   
            var_dump($this);   
        }   
           
        public function changeBandName($bandname) {   
            if ( ! is_null($this->_mediator)) {   
                $this->_mediator->change($this, array("band" => $bandname));   
            }   
            $this->band = $bandname;   
            $this->save();   
        }   
    }   
       
    //MP3Archive类   
    class MP3Archive {   
           
        protected $_mediator;   
           
        public function __construct(MusicContainerMediator $mediator = NULL) {   
            $this->_mediator = $mediator;   
        }   
           
        public function save() {   
            //具体实现待定   
            var_dump($this);   
        }   
           
        public function changeBandName($bandname) {   
            if ( ! is_null($this->_mediator)) {   
                $this->_mediator->change($this, array("band" => $bandname));   
            }   
            $this->band = $bandname;   
            $this->save();   
        }   
    }        
    //中介者类   
    class MusicContainerMediator {   
           
        protected $_containers = array();   
           
        public function __construct() {   
            $this->_containers[] = "CD";   
            $this->_containers[] = "MP3Archive";   
        }   
           
        public function change($originalObject, $newValue) {   
            $title = $originalObject->title;   
            $band  = $originalObject->band;   
               
            foreach ($this->_containers as $container) {   
                if ( ! ($originalObject instanceof $container)) {   
                    $object = new $container;   
                    $object->title = $title;   
                    $object->band  = $band;   
                       
                    foreach ($newValue as $key => $val) {   
                        $object->$key = $val;   
                    }   
                       
                    $object->save();   
                }   
            }   
        }   
    }   
       
    //测试实例   
    $titleFromDB = "Waste of a Rib";   
    $bandFromDB  = "Never Again";   
    $mediator = new MusicContainerMediator();   
    $cd = new CD($mediator);   
    $cd->title = $titleFromDB;   
    $cd->band  = $bandFromDB;   
    $cd->changeBandName("Maybe Once More");   
?> 

数据库脚本请参照：http://www.cxybl.com/html/wlbc/Php/2011_1126_9458.html