三个类概括PHP的五种设计模式

工厂模式
单元素模式
观察者模式
命令链模式
策略模式

1. class people {
2. private $name = '';
3. private $user = null;
5. private function __constract($name){/*此处private定义辅助实现 单元素模式*/
6. $this->name = $name;
7. }
9. public static function instance($name){/*此方法实现 工厂模式*/
10. static $object = null;/*此变量实现 单元素模式*/
11. if (is_null($object))
12. $object = new people($name);
13. return $object;
14. }
16. public function work_in($who=null)
17. {
18. if (is_null($who)) echo 'error';
19. else {
20. $this->user[] = $who;/*此数组变量实现 观察者模式*/
21. echo $who->work();/*此方法调用实现 策略模式*/
22. }
23. }
25. public function on_action($which=''){
26. if (empty($which)) echo 'error';
27. else {
28. foreach ($this->user as $user)
29. $user->action($which);/*此方法调用实现 命令链模式*/
30. }
31. }
32. }
34. $people = people::instance('jack');
35. $people->work_in(new student);
36. $people->work_in(new teacher);
37. $people->on_action('eat');
39. class student {
40. function work(){
41. echo '
    我是学生，朝九晚五。';
42. }
44. function action($which){
45. if (method_exists($this, $which)) return $this->$which();
46. else echo 'you are wrong!';
47. }
49. function eat(){
50. echo '
    我是学生，只能吃套餐。';
51. }
52. }
54. class teacher {
55. function work(){
56. echo '
    我是老师，晚上备课最忙。';
57. }
59. function action($which){
60. if (method_exists($this, $which)) return $this->$which();
61. else echo 'i can not do it!';
62. }
64. function eat(){
65. echo '
    我是老师，可以每天吃大餐。';
66. }
67. }

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