The SplSubject interface

(PHP 5 >= 5.1.0)

Introduzione

The SplSubject interface is used alongside SplObserver to implement the Observer Design Pattern.

Sommario dell'interfaccia

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

Indice dei contenuti

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User Contributed Notes 3 notes

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8
przemyslaw dot szpiler at gmail dot com
2 years ago
<?php

// Example implementation of Observer design pattern:

class MyObserver1 implements SplObserver {
    public function
update(SplSubject $subject) {
        echo
__CLASS__ . ' - ' . $subject->getName();
    }
}

class
MyObserver2 implements SplObserver {
    public function
update(SplSubject $subject) {
        echo
__CLASS__ . ' - ' . $subject->getName();
    }
}

class
MySubject implements SplSubject {
    private
$_observers;
    private
$_name;

    public function
__construct($name) {
       
$this->_observers = new SplObjectStorage();
       
$this->_name = $name;
    }

    public function
attach(SplObserver $observer) {
       
$this->_observers->attach($observer);
    }

    public function
detach(SplObserver $observer) {
       
$this->_observers->detach($observer);
    }

    public function
notify() {
        foreach (
$this->_observers as $observer) {
           
$observer->update($this);
        }
    }

    public function
getName() {
        return
$this->_name;
    }
}

$observer1 = new MyObserver1();
$observer2 = new MyObserver2();

$subject = new MySubject("test");

$subject->attach($observer1);
$subject->attach($observer2);
$subject->notify();

/*
will output:

MyObserver1 - test
MyObserver2 - test
*/

$subject->detach($observer2);
$subject->notify();

/*
will output:

MyObserver1 - test
*/

?>
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0
aiddroid at example dot com
1 year ago
/**
* 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 $this->content." (by {$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>';
    }
}

//classes test
$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! (by Newyork Times)
//Jim is reading breakout news USA break down! (by Newyork Times)
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0
Anonymous
1 year ago
<?php
class Observable implements SplSubject
{
    private
$storage;

    function
__construct()
    {
       
$this->storage = new SplObjectStorage();
    }

    function
attach(SplObserver $observer)
    {
       
$this->storage->attach($observer);
    }

    function
detach(SplObserver $observer)
    {
       
$this->storage->detach($observer);
    }

    function
notify()
    {
        foreach (
$this->storage as $obj) {
           
$obj->update($this);
        }
    }
   
//...
}

abstract class
Observer implements SplObserver
{
    private
$observable;

    function
__construct(Observable $observable)
    {
       
$this->observable = $observable;
       
$observable->attach($this);
    }

    function
update(SplSubject $subject)
    {
        if (
$subject === $this->observable) {
           
$this->doUpdate($subject);
        }
    }

    abstract function
doUpdate(Observable $observable);
}

class
ConcreteObserver extends Observer
{
    function
doUpdate(Observable $observable)
    {
       
//...
   
}
}

$observable = new Observable();
new
ConcreteObserver($observable);
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