final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final SearchEngineClient searchEngineClient = ComponentUtil.getSearchEngineClient();
        final IndexingHelper indexingHelper = ComponentUtil.getIndexingHelper();
        try {
            final Map<String, Object> doc = indexingHelper.getDocument(searchEngineClient, id,

         */
        protected final String imageExtention;

        /**
         * OpenSearch client for document validation.
         */
        protected final SearchEngineClient searchEngineClient;

        /**
         * Fess configuration for settings.
         */
        protected final FessConfig fessConfig;

    private static final Logger logger = LogManager.getLogger(ThumbnailGenerator.class);

    /**
     * OpenSearch client for accessing indexed documents.
     */
    @Resource
    public SearchEngineClient searchEngineClient;

    /**
     * Default constructor for ThumbnailGenerator.
     */
    public ThumbnailGenerator() {
        // Default constructor
    }

    /**

    public void setUp() throws Exception {
        super.setUp();
        crawler = new Crawler();

        // Initialize mock components
        searchEngineClient = new SearchEngineClient() {
            // Mock implementation
        };
        crawler.searchEngineClient = searchEngineClient;

        webFsIndexHelper = new WebFsIndexHelper() {
            @Override

     *
     * @param searchEngineClient the search engine client to perform the query
     * @return a list of maps containing session IDs and their document counts
     */
    public List<Map<String, String>> getSessionIdList(final SearchEngineClient searchEngineClient) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

import org.codelibs.fess.ds.callback.IndexUpdateCallback;
import org.codelibs.fess.entity.DataStoreParams;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.opensearch.config.exbhv.DataConfigBhv;
import org.codelibs.fess.opensearch.config.exentity.DataConfig;
import org.codelibs.fess.unit.UnitFessTestCase;
import org.codelibs.fess.util.ComponentUtil;

        // Note: In a real test environment, this would require proper SearchEngineClient setup
        // For now, we test that the method signature is correct and can be called

        AtomicInteger callbackCount = new AtomicInteger(0);

        try {
            // This will likely fail due to missing SearchEngineClient setup,
            // but we can verify the method signature and basic functionality

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.codelibs.fess.Constants;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.util.ComponentUtil;
import org.opensearch.action.admin.cluster.node.hotthreads.NodesHotThreadsResponse;
import org.opensearch.common.unit.TimeValue;

/**

    private IntervalControlHelper intervalControlHelper;
    private SearchLogHelper searchLogHelper;
    private LanguageHelper languageHelper;
    private FessConfig fessConfig;
    private SearchEngineClient searchEngineClient;
    private DataService<OpenSearchAccessResult> dataService;
    private UrlQueueService<OpenSearchUrlQueue> urlQueueService;
    private UrlFilterService urlFilterService;
    private ClickLogBhv clickLogBhv;

        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()