Simple example of php observer pattern

//Observed abstract class
class Observed implements SplSubject{
 protected $_name;
 protected $_observers;
 //Instantiation, generate observer object
 public function __construct(){
 $this-> ;_observers = new SplObjectStorage();
 }
 //Add observer object
 public function attach(SplObserver $observer){
 $this->_observers->attach($observer);
 }
 //Delete observer Object
 public function detach(SplObserver $observer){
 $this->_observers->detach($observer);
 }
 //Notification message
 public function notify(){
 foreach($this-> _observers as $observer){
 $observer->showMessage($this);
 }
 }
 //Normal method: Set value
 public function setName($name){
 $this->_name = $name;
 $this->notify();
 }
 //Normal method: Get value
 public function getName(){
 return $this->_name;
 }
 //Normal method: Set age
 public function setAge ($age){
 $this->age = $age;
 foreach($this->_observers as $observer){
 $observer->showAge($this->_name,$this-> age);
 }
 }
}
//Observer abstract class
class Observer implements SplObserver{
 //Show message prompt
 public function showMessage(SplSubject $obj){
 $user = $obj->getName() ;
 if($user==='admin'){
 echo 'Hello, ',$user,'Welcome to the management background';
 }else{
 echo "Hello, ' $user' You have been added to the user list";
 }
 }
 //This is an abstract method inherited from the parent class
 public function update(SplSubject $subject) {}
 //Display personal age
 public function showAge($name,$age){
 echo "<script>alert('$name's age is: $age')</script>";
 }
}
$subject = new Observed( ); //Generate an observed object
$observer = new Observer(); //Generate an observer object
$subject->attach($observer);//Pass the observer into the observed
$subject->setName('Zhang San'); //Call the setName method
/*
 * By calling $this->notify();
* By calling $this->notify () will call the $observer->showMessage($this) method,
* that is, the showMessage($obj) method of each observer object;
*/
$subject->setName('admin');
 $subject->setAge(24);

Example 2, observer mode:

interface Subject
{
public function Attach($Observer); //Add an observer
public function Detach($Observer); //Kick out the observer
public function Notify(); //Meet the conditions Notify observers when
public function SubjectState($Subject); //Observation conditions
}
class Boss Implements Subject
{
public $_action;
private $_Observer;
public function Attach($Observer)
{
$this- >_Observer[] = $Observer;
}
public function Detach($Observer)
{
$ObserverKey = array_search($Observer, $this->_Observer);
if($ObserverKey !== false)
{
unset($this->_Observer[$ObserverKey]);
}
}
public function Notify()
{
foreach($this->_Observer as $value)
{
$value->Update( );
}
}
public function SubjectState($Subject)
{
$this->_action = $Subject;
}
}
abstract class Observer
{
protected $_UserName;
protected $_Sub; __construct($Name,$Sub)
{
$this->_UserName = $Name;
$this->_Sub = $Sub;
}
public abstract function Update(); //Receive the method
} / /bbs.it-home.org
class StockObserver extends Observer
{
public function __construct($name,$sub)
{
parent::__construct($name,$sub);
}
public function Update()
 {
echo $this->_Sub->_action.$this->_UserName." Run quickly...";
}
}
$huhansan = new Boss(); //Observed person
$ gongshil = new StockObserver("三毛",$huhansan); //Initialize the observer
$huhansan->Attach($gongshil); //Add an observer
$huhansan->Attach($gongshil); / /Add an identical observer
$huhansan->Detach($gongshil); //Kick out an observer in the base
$huhansan->SubjectState("The police are coming"); //Meet the conditions that are met
 $huhansan->Notify(); //Copy code