* @throws IOException if the conversion fails.
     */
    @Override
    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
        builder.startObject();
        if (sessionId != null) {
            builder.field(SESSION_ID, sessionId);
        }
        if (filterType != null) {
            builder.field(FILTER_TYPE, filterType);
        }

     * @throws IOException if the conversion fails.
     */
    @Override
    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
        builder.startObject();
        if (transformerName != null) {
            builder.field(TRANSFORMER_NAME, transformerName);
        }
        if (data != null) {
            builder.field(DATA, data);
        }

     * @throws IOException if the conversion fails.
     */
    @Override
    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
        builder.startObject();
        if (sessionId != null) {
            builder.field(SESSION_ID, sessionId);
        }
        if (method != null) {
            builder.field(METHOD, method);
        }
        if (url != null) {

            final NodesStatsResponse response = esClient.admin().cluster().prepareNodesStats().all().execute().actionGet(10000L);
            final XContentBuilder builder = XContentFactory.jsonBuilder();
            builder.startObject();
            response.toXContent(builder, ToXContent.EMPTY_PARAMS);
            builder.endObject();
            builder.flush();
            try (OutputStream out = builder.getOutputStream()) {

        final Set<String> fieldSet = ComponentUtil.getFessConfig().getApiPingEsFieldSet();
        try (OutputStream out = SearchEngineUtil.getXContentBuilderOutputStream((builder, params) -> {
            builder.startObject();
            if (fieldSet.contains(CLUSTER_NAME)) {
                builder.field(CLUSTER_NAME, response.getClusterName());
            }
            if (fieldSet.contains(STATUS)) {

     * @throws IOException if the conversion fails.
     */
    @Override
    public XContentBuilder toXContent(final XContentBuilder builder, final Params params) throws IOException {
        builder.startObject();
        if (sessionId != null) {
            builder.field(SESSION_ID, sessionId);
        }
        if (ruleId != null) {
            builder.field(RULE_ID, ruleId);
        }
        if (url != null) {

        out.writeOptionalString(storeName);
    }

    @Override
    protected void doXContent(final XContentBuilder builder, final Params params) throws IOException {
        builder.startObject(NAME);
        if (modelName != null) {
            builder.field(MODEL_NAME.getPreferredName(), modelName);
        }
        if (featureSetName != null) {