设计模式——职责链模式

时间：2010-09-02 来源：yzxlyd

简介：

这个是关于请假、加薪的例子。

职责链模式：使多个对象都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这个对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理它为止。

需要注意的是：一个请求极有可能到了链的的末端都得不到处理，需要事先考虑全面。

一、UML图

二、代码

1 class Request {
2     public $type;
3     public $content;
4     public $num;
5 }
6
7 abstract class Manager {
8     protected $name;
9     protected $superior = NULL;
10     public function __construct($name) {
11         $this->name = $name;
12     }
13     public function SetSuperior($superior) {
14         $this->superior = $superior;
15     }
16     abstract function RequestApplications(Request $request);
17 }
18
19 class CommonManager extends Manager {
20     public function RequestApplications(Request $request) {
21         if ($request->type == '请假' && $request->num <= 2) {
22             echo "{$this->name}:{$request->content} 数量{$request->num} 被批准\n";
23         } else {
24             if (NULL !== $this->superior) {
25                 $this->superior
26                     ->RequestApplications($request);
27             }
28         }
29     }
30 }
31
32 class GeneralManage extends Manager {
33     public function RequestApplications(Request $request) {
34         if ($request->type == '请假') {
35             echo "{$this->name}:{$request->content} 数量{$request->num} 被批准\n";
36         } elseif ($request->type == '加薪' && $request->num <= 500) {
37             echo "{$this->name}:{$request->content} 数量{$request->num} 被批准\n";
38         } elseif ($request->type == '加薪' && $request->num > 500) {
39             echo "{$this->name}:{$request->content} 数量{$request->num} 再说吧\n";
40         }
41     }
42 }
43
44 $jinli = new CommonManager('经理');
45 $zhongjingli = new GeneralManage('总经理');
46 $jinli->SetSuperior($zhongjingli);
47
48 // 请假
49 $request = new Request();
50 $request->type = '请假';
51 $request->content = '小菜请假';
52 $request->num = 1;
53 $jinli->RequestApplications($request);
54 $request->num = 4;
55 $jinli->RequestApplications($request);
56
57 // 加薪
58 $request->type = '加薪';
59 $request->content = '小菜请求加薪';
60 $request->num = 500;
61 $jinli->RequestApplications($request);
62 $request->num = 1000;
63 $jinli->RequestApplications($request);