return getComponent(DATA_SERVICE);
    }

    /**
     * Gets the search engine client component.
     * @return The search engine client.
     */
    public static SearchEngineClient getSearchEngineClient() {
        return getComponent(SEARCH_ENGINE_CLIENT);
    }

    /**
     * Gets the Fess configuration component.
     * @return The Fess config.
     */

     */
    protected Function<Map<String, Object>, String[]> idFinder = params -> {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
        final String index = fessConfig.getIndexDocumentUpdateIndex();
        final Object url = params.get("url");
        if (url == null) {
            return StringUtil.EMPTY_STRINGS;
        }

     * @return A list of documents.
     */
    protected List<Map<String, Object>> getDocumentList(final KeyMatch keyMatch) {
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        return searchEngineClient.getDocumentList(fessConfig.getIndexDocumentSearchIndex(),

        contentFieldList = Arrays.asList(stream(fessConfig.getSuggestFieldContents()).get(stream -> stream.toArray(n -> new String[n])));

        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        searchEngineClient.admin()
                .cluster()
                .prepareHealth()
                .setWaitForYellowStatus()
                .execute()

        final String query = ComponentUtil.getQueryStringBuilder().params(params).sortField(params.getSort()).build();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        return ComponentUtil.getSearchEngineClient()
                .<Map<String, Object>> scrollSearch(fessConfig.getIndexDocumentSearchIndex(), searchRequestBuilder -> {
                    final QueryHelper queryHelper = ComponentUtil.getQueryHelper();

        this.systemHelper = systemHelper;
    }

    @Override
    public void expired() {
        try {
            final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
            final NodesStatsResponse response = client.admin().cluster().prepareNodesStats().addMetric("os").execute().actionGet(10000L);

            short maxCpu = 0;

     * @return the number of documents that were deleted
     */
    public long deleteBySessionId(final String sessionId) {
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String index = fessConfig.getIndexDocumentUpdateIndex();
        return deleteBySessionId(searchEngineClient, index, sessionId);

        // TODO bulk
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        try {
            ComponentUtil.getIndexingHelper()
                    .updateDocument(ComponentUtil.getSearchEngineClient(), thumbnailId, fessConfig.getIndexFieldThumbnail(), value);
        } catch (final Exception e) {
            logger.warn("Failed to update thumbnail field at {}", thumbnailId, e);
        }
    }

    /**

     *
     * @return a string containing the execution result and any error messages
     */
    public String execute() {
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

        final StringBuilder resultBuf = new StringBuilder();

        // clean up

     *
     * @return execution result message
     */
    public String execute() {
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final LabelTypeHelper labelTypeHelper = ComponentUtil.getLabelTypeHelper();