protected function getEvent() {
        if ($this->event) {
            return $this->event;
        }
        $controller = $this->getController();
        if (!$controller instanceof InjectApplicationEventInterface) {
            throw new Exception\DomainException('getParam plugin requires a controller that implements InjectApplicationEventInterface');
        }
        $event = $controller->getEvent();
        if (!$event instanceof MvcEvent) {
            $params = $event->getParams();
            $event = new MvcEvent();
            $event->setParams($params);
        }
        $this->event = $event;
        return $this->event;
    }