private function checkOverride($uri)
    {
        // 1st priority: /robots.txt is permanent allowed
        if (parse_url($uri, PHP_URL_PATH) === self::PATH) {
            return self::DIRECTIVE_ALLOW;
        }
        // 2st priority: Status code rules
        $statusCodeParser = new StatusCodeParser($this->statusCode, parse_url($this->base, PHP_URL_SCHEME));
        if (($result = $statusCodeParser->accessOverride()) !== false) {
            return $result;
        }
        // 3rd priority: Visit times
        if ($this->handler->visitTime->client()->isVisitTime() === false) {
            return self::DIRECTIVE_DISALLOW;
        }
        return false;
    }