SplSubject::attach
(PHP 5 >= 5.1.0)
SplSubject::attach — Attach an SplObserver
Description
Attaches an SplObserver so that it can be notified of updates.
Warning
This function is currently not documented; only its argument list is available.
Return Values
No value is returned.
Коментарии
The most obvious storage type for observers (stored in attach()) is array. In order to be able to detach attached objects, you should be able to identify it inside observer storage.
I suggest you attach observers this way:
$this->_observers[spl_object_hash($observer)] = $observer;
so you can detach it later if you need:
unset($this->_observers[spl_object_hash($observer)]);
i think that Observer pattern is always implemented as "static" to be called from any scope, for example:
<?php
class Observer {
//attach here the caller's scope
private static $stackTrace = array( );
public static function wasTriggeredOnce() {
//...if is not in the stack, then:
self::$stackTrace[] = max( debug_backtrace( ) );
}
}
class YourFramework {
public function launchPlatform() {
//could not let user to launch application twice!
Observer::wasTriggeredOnce();
}
}
//cause is static
Observer::hereIsnoNeedToInstantiateAgain();
?>