public function notifyObservers($arg = null)
    {
        if ($this->hasChanged()) {
            foreach ($this->getObserverSetObject() as $observerObject) {
                $observerObject->update($this, $arg);
            }
            $this->clearChanged();
        }
    }
public function notifyObservers($arg = null)
    {
        if ($this->hasChanged()) {
            foreach ($this->getObserverSetObject() as $observerObject) {
                $observerObject->update($this, $arg);
            }
            $this->clearChanged();
        }
    }
public function notifyObservers ( $ arg = null ) { if ( $ this -> hasChanged ( ) ) { foreach ( $ this -> getObserverSetObject ( ) as $ observerObject ) { $ observerObject -> update ( $ this , $ arg ) ; } $ this -> clearChanged ( ) ; } }
notify all observer

@param       mixed       $arg        optional argument
@return      void
notify all observer