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php观察者模式入门例子

程序员文章站 2022-04-06 13:45:11
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  1. class DemoSubject implements SplSubject{
  2. private $observers, $value;
  3. public function __construct(){
  4. $this->observers = array();
  5. }
  6. public function attach(SplObserver $observer){
  7. $this->observers[] = $observer;
  8. }
  9. public function detach(SplObserver $observer){
  10. if($idx = array_search($observer, $this->observers, true)){
  11. unset($this->observers[$idx]);
  12. }
  13. }
  14. public function notify(){
  15. foreach($this->observers as $observer){
  16. $observer->update($this);
  17. }
  18. }
  19. public function setValue($value){
  20. $this->value = $value;
  21. $this->notify();
  22. }
  23. public function getValue(){
  24. return $this->value;
  25. }
  26. }
  27. class DemoObserver implements SplObserver{
  28. public function update(SplSubject $subject){
  29. echo 'The new value is '. $subject->getValue();
  30. }
  31. }
  32. $subject = new DemoSubject();
  33. $observer = new DemoObserver();
  34. $subject->attach($observer);
  35. $subject->setValue(5);
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