* }
 * </pre>
 */
public class ESSourceReader implements DocumentReader {
    private static final Logger logger = LogManager.getLogger(ESSourceReader.class);

    /** Queue of documents. */
    protected final Queue<Map<String, Object>> queue = new ConcurrentLinkedQueue<>();
    /** Flag indicating if reading is finished. */
    protected final AtomicBoolean isFinished = new AtomicBoolean(false);
    /** Random number generator. */

        }
        log(logHelper, LogType.FINISHED_THREAD, crawlerContext);
    }

    /**
     * Adds sitemaps from robots.txt to the crawling queue.
     * @param urlQueue The URL queue to add sitemaps to.
     */
    protected void addSitemapsFromRobotsTxt(final UrlQueue<?> urlQueue) {
        final String[] sitemaps = crawlerContext.removeSitemaps();
        if (sitemaps != null) {

/**
 * The UrlQueue interface represents a queue of URLs to be processed by a web crawler.
 * It provides methods to get and set various properties of a URL queue entry.
 *
 * @param <IDTYPE> the type of the identifier for the URL queue entry
 */
public interface UrlQueue<IDTYPE> {

    /**
     * Retrieves the unique identifier of the URL queue.
     *
     * @return the unique identifier of type IDTYPE.
     */

    /**
     * Adds a URL to the queue.
     *
     * @param sessionId The session ID.
     * @param url The URL.
     */
    void add(String sessionId, String url);

    /**
     * Inserts a URL queue.
     *
     * @param urlQueue The URL queue.
     */
    void insert(QUEUE urlQueue);

    /**
     * Deletes a URL queue.
     *
     * @param sessionId The session ID.
     */

 *   <li>Before processing a URL ({@link #delayBeforeProcessing()})</li>
 *   <li>After processing a URL ({@link #delayAfterProcessing()})</li>
 *   <li>When there are no URLs in the queue ({@link #delayAtNoUrlInQueue()})</li>
 *   <li>While waiting for new URLs to be added to the queue ({@link #delayForWaitingNewUrl()})</li>
 * </ul>
 *
 * <p>
 * Subclasses are responsible for implementing the abstract methods to define the actual delay

            // Default constructor
        }

        /**
         * The queue for URLs waiting to be crawled.
         */
        protected Queue<OpenSearchUrlQueue> waitingQueue = new ConcurrentLinkedQueue<>();

        /**
         * The queue for URLs currently being crawled.
         */
        protected Queue<OpenSearchUrlQueue> crawlingQueue = new ConcurrentLinkedQueue<>();
    }

    /**

    /** The metadata associated with the URL queue. */
    protected String metaData;

    /** The encoding of the URL queue. */
    protected String encoding;

    /** The parent URL of the current URL in the queue. */
    protected String parentUrl;

    /** The depth of the URL in the queue. */
    protected Integer depth;

    /** The last modified timestamp of the URL in the queue. */
    protected Long lastModified;

        assertTrue(fesenClient.prepareSearch("fess_crawler.queue")
                .setQuery(QueryBuilders.termQuery("sessionId", "id1"))
                .execute()
                .actionGet()
                .getHits()
                .getTotalHits()
                .value() > 0);
        assertTrue(fesenClient.prepareSearch("fess_crawler.queue")
                .setQuery(QueryBuilders.termQuery("sessionId", "id2"))

        final Queue<String> queue = new LinkedList<>();
        queue.add(text);
        final List<String> convertedTexts = new ArrayList<>(getMaxReadingNum());
        convertedTexts.add(text);

        for (final ReadingConverter converter : converters) {
            String s;
            while ((s = queue.poll()) != null && convertedTexts.size() <= getMaxReadingNum()) {

import org.codelibs.fess.crawler.service.UrlQueueService;

import jakarta.annotation.Resource;

/**
 * The Crawler class is the main class for web crawling. It manages the crawling process,
 * including adding URLs to the queue, filtering URLs, managing crawler threads,
 * and handling the overall crawling lifecycle.
 *
 * <p>It implements the Runnable interface to be executed in a separate thread,