public function sendHeaders()
    {
        if($this->getRequesthandler()->getRequestMethod() == Jaxon::METHOD_GET)
        {
            header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
            header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
            header("Cache-Control: no-cache, must-revalidate");
            header("Pragma: no-cache");
        }

        $sCharacterSet = '';
        $sCharacterEncoding = trim($this->getOption('core.encoding'));
        if(($sCharacterEncoding) && strlen($sCharacterEncoding) > 0)
        {
            $sCharacterSet = '; charset="' . trim($sCharacterEncoding) . '"';
        }

        header('content-type: ' . $this->sContentType . ' ' . $sCharacterSet);
    }