public void switchIndex() {
        try {
            final List<String> updateIndices = new ArrayList<>();
            final String updateAlias = getUpdateAlias(index);
            final IndicesExistsResponse updateIndicesResponse =
                    client.admin().indices().prepareExists(updateAlias).execute().actionGet(suggestSettings.getIndicesTimeout());
            if (updateIndicesResponse.isExists()) {

    public void addDocumentMappingRewriteRule(final UnaryOperator<String> rule) {
        docMappingRewriteRuleList.add(rule);
    }

    public boolean updateAlias(final String newIndex) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String updateAlias = fessConfig.getIndexDocumentUpdateIndex();
        final String searchAlias = fessConfig.getIndexDocumentSearchIndex();
        final GetIndexResponse response1 =

                searchEngineClient.addMapping(docIndex, "doc", toIndex);
                if (searchEngineClient.copyDocIndex(fromIndex, toIndex, replaceAliases) && replaceAliases
                        && !searchEngineClient.updateAlias(toIndex)) {
                    logger.warn("Failed to update aliases for {} and {}", fromIndex, toIndex);
                }
            }, e -> logger.warn("Failed to reindex from {} to {}", fromIndex, toIndex, e)));