protected function handleInvalidToken($tokenBehavior = self::TOKEN_BEHAVIOR_DEFAULT)
    {
        switch ($tokenBehavior) {
            case self::TOKEN_BEHAVIOR_IGNORE:
                $status = true;
                break;

            case self::TOKEN_BEHAVIOR_INVALIDATE:
                $status = false;
                break;

            case self::TOKEN_BEHAVIOR_DENY:
            default:
                // Headers ...
                $headers = [
                    'HTTP/1.0 400 Bad Request',
                    sprintf('WWW-Authenticate: x-doozr-form-service-token realm="%s"', $this->generateToken()),
                ];

                // Need to be sure to be able to send header, otherwise we need to stop operation
                if (false === headers_sent($file, $line)) {
                    foreach ($headers as $header) {
                        header($header);
                    }
                }
                exit;
                break;
        }

        return $status;
    }