*/
    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;
        }

        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 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();

        final String timeout = fessConfig.getCrawlerHotthreadTimeout();
        final String type = fessConfig.getCrawlerHotthreadType();
        try {
            final SearchEngineClient esClient = ComponentUtil.getSearchEngineClient();
            final NodesHotThreadsResponse response = esClient.admin()
                    .cluster()
                    .prepareNodesHotThreads()
                    .setIgnoreIdleThreads(ignoreIdleThreads)

    /**
     * Executes the ping job.
     *
     * @return the execution result
     */
    public String execute() {
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();

        final StringBuilder resultBuf = new StringBuilder();

        final List<LogNotificationEvent> events = helper.drainAll();
        if (events.isEmpty()) {
            return;
        }

        try {
            final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
            final String hostname = ComponentUtil.getSystemHelper().getHostname();
            final String indexName = resolveIndexName();

            ensureIndexExists(client, indexName);

     * @return the number of documents processed
     */
    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));
    }

    /**

        }

        if (!fessConfig.hasNotification()) {
            return "No notification targets configured.";
        }

        final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
        final String indexName = fessConfig.getIndexLogIndex() + ".notification_queue";

        if (!client.existsIndex(indexName)) {
            return "No log notifications.";
        }

        buf.append("},");
    }

    private void appendFesenStats(final StringBuilder buf) {
        String stats = null;
        try {
            final SearchEngineClient esClient = ComponentUtil.getSearchEngineClient();
            final NodesStatsResponse response = esClient.admin().cluster().prepareNodesStats().all().execute().actionGet(10000L);
            final XContentBuilder builder = XContentFactory.jsonBuilder();