public function getHTTPServerFactory(CNabuHTTPServerInterfaceDescriptor $nb_descriptor)
    {
        if (!($retval = $this->nb_http_server_factory_list->getItem($nb_descriptor->getKey()))) {
            $retval = $this->nb_http_server_factory_list->addItem(new CNabuHTTPServerFactory($nb_descriptor));
        }

        return $retval;
    }