return "lang";
                case FessConfig.INDEX_FIELD_has_cache:
                    return "has_cache";
                case FessConfig.INDEX_FIELD_last_modified:
                    return "last_modified";
                case FessConfig.INDEX_FIELD_ANCHOR:
                    return "anchor";
                case FessConfig.INDEX_FIELD_SEGMENT:
                    return "segment";

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

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

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

            @Override

                return "lang,role,label,anchor,virtual_host";
            }

            @Override
            public String getIndexAdminDateFields() {
                return "expires,created,timestamp,last_modified";
            }

            @Override
            public String getIndexAdminIntegerFields() {
                return "";
            }

            @Override

                                    <div class="col-sm-9">
                                        <la:errors property="doc.last_modified"/>
                                        <la:text styleId="doc.last_modified"
                                                 property="doc.last_modified" styleClass="form-control"

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

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

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

            @Override

                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"));

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

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

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

            @Override

# 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

        // last_modified
        final Date lastModified = responseData.getLastModified();
        if (lastModified != null) {
            putResultDataBody(dataMap, fessConfig.getIndexFieldLastModified(), lastModified);
            // timestamp
            putResultDataBody(dataMap, fessConfig.getIndexFieldTimestamp(), lastModified);
        } else {
            // timestamp