protected function executeSubAction($action) {
    $curRequest = $this->getRequest();
    $subRequest = ObjectFactory::getNewInstance('request');
    $subRequest->setSender(get_class($this));
    $subRequest->setContext($curRequest->getContext());
    $subRequest->setAction($action);
    $subRequest->setHeaders($curRequest->getHeaders());
    $subRequest->setValues($curRequest->getValues());
    $subRequest->setFormat('null');
    $subRequest->setResponseFormat('null');
    $subResponse = ObjectFactory::getNewInstance('response');
    $this->actionMapper->processAction($subRequest, $subResponse);
    return $subResponse;
  }