PHP5+标准函数库观察者之实现

PHP的观察者设计模式实现相对简单，但是PHP5+版本中已经有标准库类库支持，我们只需简单继承并实现就可以了。

观察者：实现标准接口类库SplSubject。一个注册方法：attach，一个取消注册方法：detach。一个通知方法：nofity。

<?phpclass TSPLSubject implements SplSubject{	 private $observers, $value;	 public function __construct(){		$this->observers =array();	 }	 public function attach(SplObserver $observer){		$this->observers[] = $observer;	 }	 public function detach(SplObserver $observer){		if($idx = array_search($observer, $this->observers,true)) {			unset($this->observers[$idx]);		}	 }	     /**	 *	 * Notify observers one by one (main entry)	 *	 * @param none	 * @return none	 */	 public function notify(){		foreach($this->observers as $observer){			$observer->update($this);		}	 }	 public function setValue($value){		$this->value = $value;		//$this->notify();	 }	 public function getValue(){		 return $this->value;	 }}

被观察者：实现标准接口类库SplObserver。一个update方法。

<?phpclass TSPLObserver implements SplObserver{	 public function update(SplSubject $subject){		 echo 'The new state of subject ' , nl2br("\r\n");//		 echo 'The new state of subject '.$subject->getValue();	 }}

<?phpclass TSPLObserver1 implements SplObserver{	 public function update(SplSubject $subject){		 echo 'The new state of subject one ' , nl2br("\r\n");//		 echo 'The new state of subject '.$subject->getValue();	 }}

测试调用（同目录下）：

<?phpfunction __autoload($classname) {   require_once ($classname . ".php"); }$subject = new TSPLSubject();$subject->attach(new TSPLObserver());$observer1 = new TSPLObserver1();$subject->attach($observer1);//$subject->attach(new TSPLObserver2());//$subject->detach($observer1);$subject->notify();exit();

输出：

>php basic.php
The new state of subject

The new state of subject one