14Intermediary model

<?php
class Book{
    private $name;
    private $obj=NULL;
    public $price;
    
    function __construct($name, $price, Intermediar $obj){
        $this->name = $name;
        $this->price = $price;
        $this->obj = $obj;
    }
    
    function changprice($newprice){
        $this->obj->change($this, $newprice);
    }
}

/* 
 * 实际情况中类差别很大可能无法创建父类
 *  */
class Computer{
    private $name;
    private $obj;
    public $price;
    
    function __construct($name, $price, Intermediar $obj){
        $this->name = $name;
        $this->price = $price;
        $this->obj = $obj;
    }
    
    function changprice($newprice){
        $this->obj->change($this, $newprice);
    }
}


/* 
 * 中介者类
 * 
 *  */
class Intermediar{
    public function change($obj, $value){
        $obj->price = $value;
    }
}

$inter = new Intermediar();
$label = new Book('book', 34, $inter);

$label->changprice(100);

var_dump($label);