private function loadController($class)
    {
        $controller = new $class($this->currentControllerAliasConfig);
        if (!is_a($controller, '\\mpf\\web\\Controller')) {
            $this->critical('Controller `' . $class . '` must extend \\mpf\\web\\Controller!', array(
                'requestedController' => $this->request()->getController(),
                'requestedModule' => $this->request()->getModule()
            ));
            return null;
        }
        return $controller;
    }