return searchEngineClient.getDocument(fessConfig.getIndexDocumentUpdateIndex(), builder -> {
            builder.setQuery(QueryBuilders.idsQuery().addIds(id));
            builder.setFetchSource(fields, null);
            return true;
        }).orElse(null);
    }

    /**
     * Retrieves a list of documents whose IDs start with the specified prefix.
     *

        if (_conditionAggregation != null) {
            _conditionAggregation.getAggregationBuilderList().forEach(builder::addAggregation);
        }

        if (_specification != null) {
            builder.setFetchSource(_specification.columnList.toArray(new String[_specification.columnList.size()]), null);
        }

        return builder;
    }

            if (!roleSet.isEmpty()) {
                queryHelper.buildRoleQuery(roleSet, boolQuery);
            }
            builder.setQuery(boolQuery);
            builder.setFetchSource(fields, null);
            queryHelper.processSearchPreference(builder, userBean, docId);
            return true;
        });

    }

    /**
     * Retrieves multiple documents by their document IDs.

                    searchRequestBuilder.setQuery(
                            QueryBuilders.termsQuery(docIdField, deleteFileMap.keySet().toArray(new String[deleteFileMap.size()])));
                    searchRequestBuilder.setFetchSource(new String[] { docIdField }, StringUtil.EMPTY_STRINGS);
                    return true;
                }).forEach(m -> {
                    final Object docId = m.get(docIdField);