大话设计模式第六章---装饰模式PHP实现

 1 <?php
 2 abstract class Component {
 3     abstract public function operation();
 4 }
 5
 6 class Concrete_component extends Component {
 7     public function operation() {
 8         echo "具体对象的操作<br/>";
 9     }
10 }
11
12 abstract class Decorator extends Component {
13     protected $component;
14
15     public function set_component(Component $component) {
16         $this->component = $component;
17     }
18
19     public function operation() {
20         if ($this->component != null) {
21             $this->component->operation();
22         }
23     }
24 }
25
26 class Concrete_decorator_A extends Decorator {
27     private $added_state;    //鏈被鐗规湁鐨勫姛鑳斤紝浠ュ尯鍒玞oncrete_decorator_A
28
29     public function operation() {
30         parent::operation();
31         $added_state = ‘New State‘;
32         echo "具体装饰对象A的操作<br/>";
33     }
34 }
35
36 class Concrete_decorator_B extends Decorator {
37     public function operation() {
38         parent::operation();
39         $this->added_behavior();
40         echo "具体装饰对象B的操作<br/>";
41     }
42
43     private function added_behavior(){
44     }
45 }
46
47
48
49 //涓嬮潰鏄鎴风浠ｇ爜
50 $c  = new Concrete_component();
51 $d1 = new Concrete_decorator_A();
52 $d2 = new Concrete_decorator_B();
53
54 $d1->set_component($c);
55 $d2->set_component($d1);
56 $d2->operation();

装饰模式：

　　动态地给一个对象添加一些额外的职责，就增加功能来说，装饰模式比生成子类更灵活。

　　装饰模式是利用set_component来对对象进行包装的。这样，每个装饰对象的实现就和如何使用这个对象分离开了，每个装饰对象只关心自己的功能，不需要关心如何被添加到对象链接中。