java要引入工厂和仓库的概念，而php只需要两三行代码就完成了同样的功能
/** * 领域模型父类 * 实现数据延迟载入、注册为唯一 * @author liuxu * */abstract class domain{ protected $_id; protected $_id2; protected $_fields = array(); protected $_loadedbyid = false; static protected $_objs; private function __construct($id,$id2=0) { $this->_id = $id?$id:0; $this->_id2 = $id2?$id2:0; } static public function factory($id,$id2=0) { $class = get_called_class(); if(!isset(self::$_objs[$class][$id][$id2]))//注册为唯一 { self::$_objs[$class][$id][$id2] = new $class($id,$id2); } return self::$_objs[$class][$id][$id2]; } public function load($fields=array()) { if($fields) { foreach($fields as $key=>$value) { $this->_fields[$key] = $value; } } } public function wash() { $this->_fields = array(); } //载入完整数据 abstract protected function loadbyid(); public function __get($field) { if(!isset($this->_fields[$field]) && !$this->_loadedbyid) { //延迟载入 $this->loadbyid(); $this->_loadedbyid = true; } $value = isset($this->_fields[$field])?$this->_fields[$field]:null; return $value; } }
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