<?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);