/** The key of the configuration. e.g. 1.0 */
    String QUERY_BOOST_TITLE_LANG = "query.boost.title.lang";

    /** The key of the configuration. e.g. 0.05 */
    String QUERY_BOOST_CONTENT = "query.boost.content";

    /** The key of the configuration. e.g. 0.1 */
    String QUERY_BOOST_CONTENT_LANG = "query.boost.content.lang";

    /** The key of the configuration. e.g. -1.0 */