*/
    public static long scroll(final String index, final Function<SearchHit, Boolean> callback) {
        final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
        return client.<SearchHit> scrollSearch(index, searchRequestBuilder -> true, (searchResponse, hit) -> hit,
                hit -> callback.apply(hit));
    }

    /**

     * @param cursor Function to process each document in the result set
     * @param userBean Optional user information for permission checking
     * @return Total number of documents processed
     */
    public long scrollSearch(final SearchRequestParams params, final BooleanFunction<Map<String, Object>> cursor,
            final OptionalThing<FessUserBean> userBean) {
        LaRequestUtil.getOptionalRequest().ifPresent(request -> {

        final JsonRequestParams params = new JsonRequestParams(request, fessConfig);
        try {
            response.setContentType("application/x-ndjson; charset=UTF-8");
            final long count = searchHelper.scrollSearch(params, doc -> {
                buf.setLength(0);
                buf.append('{');
                boolean first2 = true;
                for (final Map.Entry<String, Object> entry : doc.entrySet()) {

        if (numFound > fessConfig.getIndexerMaxResultWindowSizeAsInteger().longValue()) {
            final List<Map<String, Object>> entityList = new ArrayList<>(Long.valueOf(numFound).intValue());
            searchEngineClient.scrollSearch(fessConfig.getIndexDocumentUpdateIndex(), requestBuilder -> {
                requestBuilder.setQuery(queryBuilder).setSize((int) numFound);
                if (fields != null) {

     * @return the number of documents processed
     * @throws InvalidQueryException if the query is invalid
     */
    public long scrollSearch(final String index, final SearchCondition<SearchRequestBuilder> condition,
            final BooleanFunction<Map<String, Object>> cursor) {
        return scrollSearch(index, condition, getDefaultEntityCreator(), cursor);
    }

    /**