装饰器模式

<?php//装饰器模式-在不改变原有类的结构上，对类的功能那个作补充//武器基类abstract class Weapon{    abstract public function descriptions();    abstract public function cost();}//剑类class Glave extends Weapon{    public function descriptions(){        return 'Glave';    }        public function cost(){        return "100";    }}//匕首类class Knife extends Weapon{    public function descriptions(){        return __CLASS__;    }    public function cost(){        return "80";    }}//斧类class Axe extends Weapon{    public function descriptions(){        return  __CLASS__;    }    public function cost(){        return "200";    }}//属性类class PRoperty extends Weapon{    protected $_weapon = null;    protected $_price = 0;    protected $_descriptions = '';    public function __construct(Weapon $weapon){        $this->_weapon = $weapon;    }    public function cost(){        return     $this->_weapon->cost() + $this->_price;    }        public function descriptions(){        return $this->_weapon->descriptions().$this->_descriptions;    }}//力量属性class Strength extends Property{    protected $_price = 30;    protected $_descriptions = '+ Strength';}//敏捷属性class Agility extends Property{    protected $_price = 50;    protected $_descriptions = '+ Agility';}//智力属性class Intellect extends Property{    protected $_price = 20;    protected $_descriptions = '+ Intellect';}$weapon = new Agility(new Strength(new Strength(new Glave())));echo $weapon->cost();echo $weapon->descriptions();