private function handleIdentity(OrderInterface $order)
    {
        if (null !== $user = $order->getUser()) {
            if (0 == strlen($order->getEmail())) {
                $order->setEmail($user->getEmail());
            }
            if (0 == strlen($order->getGender())) {
                $order->setGender($user->getGender());
            }
            if (0 == strlen($order->getFirstName())) {
                $order->setFirstName($user->getFirstName());
            }
            if (0 == strlen($order->getLastName())) {
                $order->setLastName($user->getLastName());
            }
        }
    }