public String getIndexFieldSite() {
                return "site";
            }

            @Override
            public String getIndexFieldLastModified() {
                return "last_modified";
            }

            @Override
            public String getIndexFieldTimestamp() {
                return "timestamp";
            }

            @Override

                        host:
                          type: string
                          format: hostname
                          example: "fess.codelibs.org"
                        last_modified:
                          type: string
                          format: date-time
                          example: "2017-10-09T22:28:56.000Z"
                        content_length:

                Set.of(), //
                "{\"timestamp\":{\"order\":\"desc\"}}{\"last_modified\":{\"order\":\"asc\"}}", //
                buildQuery("sort:timestamp.desc sort:last_modified"));
        assertQueryContext(query, Map.of(), //
                Set.of(), //
                "{\"timestamp\":{\"order\":\"desc\"}}{\"last_modified\":{\"order\":\"desc\"}}", //
                buildQuery("sort:timestamp.desc sort:last_modified.desc"));

# Field name for language in the index.
index.field.lang=lang
# Field name for cache status in the index.
index.field.has_cache=has_cache
# Field name for last modified date in the index.
index.field.last_modified=last_modified
# Field name for anchor in the index.
index.field.anchor=anchor
# Field name for segment in the index.
index.field.segment=segment
# Field name for role in the index.
index.field.role=role

            public String getIndexFieldSite() {
                return "site";
            }

            @Override
            public String getIndexFieldLastModified() {
                return "last_modified";
            }

            @Override
            public String getIndexFieldTimestamp() {
                return "timestamp";
            }

            @Override

    /** The key of the configuration. e.g. has_cache */
    String INDEX_FIELD_has_cache = "index.field.has_cache";

    /** The key of the configuration. e.g. last_modified */
    String INDEX_FIELD_last_modified = "index.field.last_modified";

    /** The key of the configuration. e.g. anchor */
    String INDEX_FIELD_ANCHOR = "index.field.anchor";

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

  /** The HTTP {@code Expires} header field name. */
  public static final String EXPIRES = "Expires";

  /** The HTTP {@code Last-Modified} header field name. */
  public static final String LAST_MODIFIED = "Last-Modified";

  /** The HTTP {@code Link} header field name. */
  public static final String LINK = "Link";

  /** The HTTP {@code Location} header field name. */