Edit Report a Bug

    L'interface SplObserver

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    Introduction

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

    Sommaire de l'Interface

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

    Sommaire

    add a note add a note

    User Contributed Notes 2 notes

    up
    87
    aiddroid at example dot com
    11 years 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)
    up
    86
    sebastien dot ferrandez at free dot fr
    10 years 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.
    add a note add a note
    To Top