SplSubject::attach

(PHP 5 >= 5.1.0, PHP 7)

SplSubject::attachAttach an SplObserver

Descrição

abstract public SplSubject::attach ( SplObserver $observer ) : void

Attaches an SplObserver so that it can be notified of updates.

Aviso

Esta função não está documentada; somente a lista de argumentos está disponível.

Parâmetros

observer

The SplObserver to attach.

Valor Retornado

Não há valor retornado.

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User Contributed Notes 2 notes

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1
workspace dot development at yahoo dot com
10 years ago
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();
?>
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0
goran
10 years ago
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)]);
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