public static function getControllers($extensionId) {
        try {
            $controllerClasses = ServiceManager::getServiceManager()->get('generis/cache')->get(self::EXTENSION_PREFIX.$extensionId);
        } catch (\common_cache_NotFoundException $e) {
            $factory = new Factory();
            $controllerClasses = array();
            foreach ($factory->getControllers($extensionId) as $controller) {
                $controllerClasses[] = $controller->getClassName();
            }
            ServiceManager::getServiceManager()->get('generis/cache')->put($controllerClasses, self::EXTENSION_PREFIX.$extensionId);
        }
        return $controllerClasses;
    }