public final function setContentLength($length)
    {
        if (! is_numeric($length)) {

            throw new
                ehough_shortstop_api_exception_InvalidArgumentException("Content-Length must be an integer ($length)");
        }

        $length = intval($length);

        if ($length < 0) {

            throw new
                ehough_shortstop_api_exception_InvalidArgumentException("Content-Length cannot be negative ($length)");
        }

        $this->_contentLength = $length;
    }