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

            public String getIndexFieldHost() {
                return "host";
            }

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

            @Override
            public String getIndexFieldMimetype() {
                return "mimetype";
            }

            @Override

            final Date lastModified = FessFunctions.parseDate(lastModifiedObj.toString());
            if (lastModified != null) {
                return lastModified;
            }
        } else if (lastModifiedObj instanceof final String[] lastModifieds && lastModifieds.length > 0) {
            final Date lastModified = FessFunctions.parseDate(lastModifieds[0]);
            if (lastModified != null) {

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

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

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

            @Override

            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"));

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

                    return true;
                }

                final Date lastModified = DocumentUtil.getValue(document, fessConfig.getIndexFieldLastModified(), Date.class);
                if (lastModified == null) {
                    return true;
                }
                urlQueue.setLastModified(lastModified.getTime());
                log(logHelper, LogType.CHECK_LAST_MODIFIED, crawlerContext, urlQueue);

                map.put("size", item.size());
                map.put("directory", item.isDir());
                if (!item.isDir()) {
                    map.put("lastModified", item.lastModified());
                    fileList.add(map);
                } else {
                    list.add(map);
                }