Using OOP serialize the chain of php,always used to handle the DB.

chain of php.php

<?php
/**
 * Created by JetBrains PhpStorm.
 * User: zhangxy
 * Date: 13-3-5
 * Time: 下午2:31
 */
error_reporting(E_ALL | E_STRICT);

class Base_OOP_VAR{
    private $_trace_data = array();
    protected $_methods = array();
    protected $_data;

    public function __construct($data){
        $this->_data = $data;
        $this->_trace_data['__construct'] = $data;
        return $this->_data;

    }
    public function __toString(){
        if(is_int($this->_data) || is_float($this->_data)){
            $this->_data = (string)$this->_data;
        }
        return $this->_data;
    }
    //魔术方法提供链式操作的方法传递到methods数组中
    public function __call($name,$args){
        $this->valid_func($name);
        if(!$args)  $args = $this->_data;
        $this->_data = call_user_func($name, $args);
        $this->_trace_data[$name] = $this->_data;
        return $this;
    }
    //检查方法是否有效
    private function valid_func($name){
        if(!in_array($name, $this->_methods)){
            throw new Exception('invalid method:' . $name . ' in ' . var_dump($this->_methods));
        }
    }
    //打印trace信息
    public function trace(){
        echo "<pre>";
        var_dump($this->_trace_data);
        echo "</pre>";
    }

}


class String extends Base_OOP_VAR{
        protected $_methods = array(
            'trim',
            'strlen',
            'gettype'
        );
}

$a = new String('  Hello world ! ');
echo $a->trim()->strlen()->gettype();
$a->trace();