/** The key of the configuration. e.g. fess_log */
    String INDEX_LOG_INDEX = "index.log.index";

    /** The key of the configuration. e.g. lang,role,label,anchor,virtual_host */
    String INDEX_ADMIN_ARRAY_FIELDS = "index.admin.array.fields";

    /** The key of the configuration. e.g. expires,created,timestamp,last_modified */
    String INDEX_ADMIN_DATE_FIELDS = "index.admin.date.fields";

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