public function defaultQueryMethod($query, $config)
    {
        switch (strtolower($this->config('search_using', 'plain'))) {
            case 'tsquery':
                return new ToTsQuery($query, $config);
            case 'phrasequery':
                return new PhraseToTsQuery($query, $config);
            case 'plainquery':
            default:
                return new PlainToTsQuery($query, $config);
        }
    }