PHP设计模式装饰器模式

<?php namespace Test;abstract class Component{   abstract public function operation(); }

<?phpnamespace Test;abstract class Decorator extends Component{    protected $component;    public function __construct(Component $component)    {        $this->component = $component;    }    public function operation()    {        $this->component->operation();    }    abstract public function before();    abstract public function after();}

<?phpnamespace Test;class ConcreteComponent extends Component{    public function operation()    {        echo "hello world!!!!";    }}

<?phpnamespace Test;class ConcreteDecoratorA extends Decorator{    public function __construct(Component $component)    {        parent::__construct($component);    }    public function operation() {        $this->before();        parent::operation();        $this->after();    }    public function before()    {        // TODO: Implement before() method.        echo "before!!!";    }    public function after()    {        // TODO: Implement after() method.        echo "after!!!";    }}

<?phpnamespace Test;class Client{    /**     *     */    public static function main() {        $decoratorA = new ConcreteDecoratorA(new ConcreteComponent());        $decoratorA->operation();        $decoratorB=new ConcreteDecoratorA($decoratorA);        $decoratorB->operation();    }}

before!!!hello world!!!!after!!!before!!!before!!!hello world!!!!after!!!after!!!