SplSubject {
/* 方法 */
abstract public void attach ( SplObserver $observer )
abstract public void detach ( SplObserver $observer )
abstract public void notify ( void )
}

SplObserver {
/* 方法 */
abstract public void update ( SplSubject $subject )
}

<?php
/*** Subject,that who makes news*/
class Newspaper implements \SplSubject{private $name;private $observers = array();private $content;public function __construct($name) {$this->name = $name;}//add observerpublic function attach(\SplObserver $observer) {$this->observers[] = $observer;}//remove observerpublic function detach(\SplObserver $observer) {$key = array_search($observer,$this->observers, true);if($key){unset($this->observers[$key]);}}//set breakouts newspublic function breakOutNews($content) {$this->content = $content;$this->notify();}public function getContent() {return $this->content." ({$this->name})";}//notify observers(or some of them)public function notify() {foreach ($this->observers as $value) {$value->update($this);}}
}/*** Observer,that who recieves news*/
class Reader implements SplObserver{private $name;public function __construct($name) {$this->name = $name;}public function update(\SplSubject $subject) {echo $this->name.' is reading breakout news <b>'.$subject->getContent().'</b><br>';}
}$newspaper = new Newspaper('Newyork Times');$allen = new Reader('Allen');
$jim = new Reader('Jim');
$linda = new Reader('Linda');//add reader
$newspaper->attach($allen);
$newspaper->attach($jim);
$newspaper->attach($linda);//remove reader
$newspaper->detach($linda);//set break outs
$newspaper->breakOutNews('USA break down!');//=====output======
//Allen is reading breakout news USA break down! (Newyork Times)
//Jim is reading breakout news USA break down! (Newyork Times)

<?php$ObjectStorage = new SplObjectStorage();class classa{#code...}class classb{#code...}$a = new classa();
$b = new classb();$ObjectStorage->attach($a);
$ObjectStorage->attach($b);
$ObjectStorage->attach($a);foreach ($ObjectStorage as $key => $item) {echo ($key+1).'、'.(new ReflectionClass($item))->getName()."\n";
}

//output

1、classa
  2、classb
  [Finished in 0.1s]

?>

<?php
/*** Subject,that who makes news*/
class Newspaper implements \SplSubject{private $name;private $observers;private $content;public function __construct($name) {$this->name = $name;$this->observers = new SplObjectStorage();}//add observerpublic function attach(\SplObserver $observer) {$this->observers -> attach($observer);}//remove observerpublic function detach(\SplObserver $observer) {$this->observers -> detach($observer);}//set breakouts newspublic function breakOutNews($content) {$this->content = $content;$this->notify();}public function getContent() {return $this->content." ({$this->name})";}//notify observers(or some of them)public function notify() {foreach ($this->observers as $value) {$value->update($this);}}
}/*** Observer,that who recieves news*/
class Reader implements SplObserver{private $name;public function __construct($name) {$this->name = $name;}public function update(\SplSubject $subject) {echo $this->name.' is reading breakout news '.$subject->getContent()."\n";}
}$newspaper = new Newspaper('Newyork Times');$allen = new Reader('Allen');
$jim = new Reader('Jim');
$linda = new Reader('Linda');//add reader
$newspaper->attach($allen);
$newspaper->attach($jim);
$newspaper->attach($linda);//remove reader
$newspaper->detach($linda);//set break outs
$newspaper->breakOutNews('USA break down!');//=====output======
//Allen is reading breakout news USA break down! (Newyork Times)
//Jim is reading breakout news USA break down! (Newyork Times)