PHP 5.4.33 Released

L'interface SplObserver

(PHP 5 >= 5.1.0)

Introduction

L'interface SplObserver est utilisée conjointement avec la classe SplSubject pour l'implémentation du patron de conception Observateur.

Sommaire de l'Interface

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

Sommaire

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User Contributed Notes 2 notes

up
10
sebastien dot ferrandez at free dot fr
6 months ago
Beware, you have written :

        if($key){
            unset($this->observers[$key]);
        }

When this should be :

        if(false !== $key){
            unset($this->observers[$key]);
        }

If the observer you want to delete is the first in your array, you will never delete it because the key would equal 0 and 0 == false as you know.
up
10
aiddroid at example dot com
1 year ago
<?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 observer
   
public function attach(\SplObserver $observer) {
       
$this->observers[] = $observer;
    }
   
   
//remove observer
   
public function detach(\SplObserver $observer) {
       
       
$key = array_search($observer,$this->observers, true);
        if(
$key){
            unset(
$this->observers[$key]);
        }
    }
   
   
//set breakouts news
   
public 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)
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