Observer Observer pattern in php

Observer pattern

Copy code The code is as follows:

interface Subject
{
public function Attach($Observer); //Add an observer
public function Detach($Observer); //Kick out the observer
public function Notify(); //Notify the observer when the conditions are met
public function SubjectState($Subject); //Observe the 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 $_Sub;
public function __construct($Name,$Sub)
{
$this->_UserName = $Name;
$this->_Sub = $Sub;
}
public abstract function Update (); //Receive via method
}
class StockObserver extends Observer
{
public function __construct($name,$sub)
{
parent::__construct($name,$sub);
}
public function Update( )
{
echo $this->_Sub->_action.$this->_UserName." Run quickly...";
}
}
$huhansan = new Boss(); // Observer
$gongshil = new StockObserver("三毛",$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"); //Achieve satisfactory results Condition
$huhansan->Notify(); //All valid observers

can be roughly understood as a class (we call it the observer), which inherits an observer container Excuse
The methods in this interface are: add observer, kick out observer, remind observer, and observation conditions
Adding observer is equivalent to registering some classes into this container. Of course, the premise of these classes is that they need to have A method to respond to the response information of the observer.
The observer container determines whether it needs to remind all registered observers in the container by accepting different observation condition parameters.
Once the reminder condition is met, all the observers in the container will be reminded. The observer allows it to call the corresponding method and implement changes to the corresponding observer instance
That’s all for now!

The above introduces the observer mode in php, including observer aspects. I hope it will be helpful to friends who are interested in PHP tutorials.