public function addByHttpCode($nCode)
    {
        $sProtocol = isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL']
                : 'HTTP/1.1';
        $sHeader   = "{$sProtocol} {$nCode} "
            .self::getHTTPExplanationByCode($nCode);
        return $this->add($sHeader);
    }