PHP对象链式操作实现原理分析

$("p").css("color").addClass("selected");

$str = 'abs123 ';echo strlen(trim($str));

$str = 'abs123 ';echo $str->trim()->strlen();

/***  对象链式操作*    2015-04-24*/class BaseChainObject{    /*** 追溯数据，用来进行调试* @var array*/private $_trace_data = array();    /**    *    保存可用方法列表    *    @param array    */    protected $_methods = array();    /**    *    处理的数据    *    @param null    */    public $data;    function __construct($data){        $this->data = $data;        $this->_trace_data['__construct'] = $data;        return $this->data;    }    function __toString(){        return (String)$this->data;    }    function __call($name,$args){        try{            $this->vaild_func($name);        }catch(Exception $e){            echo $e->getMessage();            exit();        }        if (!$args) {            $args = $this->data;            $this->data = call_user_func($name,$args);        }else{            $this->data = call_user_func_array($name,$args);        }        $this->_trace_data[$name] = $this->data;        return $this;    }    /**    *    判断方法是否存在    *    @param string    */    private function vaild_func($fn){        if(!in_array($fn, $this->_methods)){            throw new Exception("unvaild method");        }    }    public function trace(){      var_dump($this->_trace_data);    }}class String extends BaseChainObject{    protected $_methods = array('trim','strlen');}$str = new String('ab rewqc ');echo $str->trim()->strlen();$str->trace();