Observer pattern interface for Joomla

A class that wants to observe another class must:

1) Add: implements JObserverInterface to its class

2) Implement a constructor, that can look like this: public function __construct(JObservableInterface $observableObject) { $observableObject->attachObserver($this); $this->observableObject = $observableObject; }

3) and must implement the instanciator function createObserver() below, e.g. as follows: public static function createObserver(JObservableInterface $observableObject, $params = array()) { $observer = new self($observableObject); $observer->... = $params['...']; ... return $observer; }

4) Then add functions corresponding to the events to be observed, E.g. to respond to event: $this->_observers->update('onBeforeLoad', array($keys, $reset)); following function is needed in the obser: public function onBeforeLoad($keys, $reset) { ... }

5) Finally, the binding is made outside the observable and observer classes, using: JObserverMapper::addObserverClassToClass('ObserverClassname', 'ObservableClassname', array('paramName' => 'paramValue')); where the last array will be provided to the observer instanciator function createObserver.

• link: http://docs.joomla.org/JObserverInterface
• since: 3.1.2

Located in /libraries/joomla/observer/interface.php (line 49)