public function registerHook($eventType, IEventHook $hook)
    {
        switch ($eventType) {
            case IEventHook::EVENT_SAVE_CHANGES:
                $this->getDataUpdater()->registerSaveChangesEventHook($hook);
                break;
            default:
                throw new Exception("Unrecognised type $eventType whilst registering event hook");
        }
    }