* {@link #isContinue(int)} method returns {@code false}.
 * </p>
 *
 */
public class CrawlerThread implements Runnable {
    /**
     * Constructs a new CrawlerThread.
     */
    public CrawlerThread() {
        // Default constructor
    }

    /**
     * Service for managing URL queues during crawling.
     */
    @Resource

        for (int i = 0; i < crawlerContext.getNumOfThread(); i++) {
            final CrawlerThread crawlerThread = crawlerContainer.getComponent("crawlerThread");
            crawlerThread.setCrawlerContext(crawlerContext);
            crawlerThread.setClientFactory(clientFactory);
            threads[i] =
                    new Thread(crawlerThreadGroup, crawlerThread, "Crawler-" + crawlerContext.sessionId + "-" + Integer.toString(i + 1));

    public void test_getClientRuleList() {
        FessCrawlerThread crawlerThread = new FessCrawlerThread();

        List<Pair<String, Pattern>> list = crawlerThread.getClientRuleList(null);
        assertEquals(0, list.size());

        list = crawlerThread.getClientRuleList("");
        assertEquals(0, list.size());

        list = crawlerThread.getClientRuleList(" ");
        assertEquals(0, list.size());

	<!-- Crawler -->
	<component name="crawler" class="org.codelibs.fess.crawler.Crawler" instance="prototype" >
	</component>

	<!-- Crawler Thread -->
	<component name="crawlerThread" class="org.codelibs.fess.crawler.CrawlerThread" instance="prototype" >
	</component>

	<!-- Entity -->
	<component name="accessResult"
		class="org.codelibs.fess.crawler.entity.OpenSearchAccessResult" instance="prototype">
	</component>

     *
     * @param crawlerThread the thread to wait for; null threads are ignored
     */
    private void joinCrawlerThread(final Thread crawlerThread) {
        if (crawlerThread != null) {
            try {
                crawlerThread.join();
            } catch (final Exception e) {
                logger.info("Interrupted a crawling process: {}", crawlerThread.getName());
            }
        }
    }

        })
                .prototype("accessResult", AccessResultImpl.class)
                .prototype("urlQueue", UrlQueueImpl.class)
                .prototype("crawlerThread", CrawlerThread.class)
                .prototype("crawler", Crawler.class)
                .prototype("urlFilterService", UrlFilterServiceImpl.class)
                .prototype("urlQueueService", UrlQueueServiceImpl.class)

 * <li>Integration with Fess configuration and permission systems</li>
 * <li>Client selection based on URL patterns</li>
 * </ul>
 *
 * @see CrawlerThread
 * @see org.codelibs.fess.crawler.client.CrawlerClient
 */
public class FessCrawlerThread extends CrawlerThread {

    /**
     * Default constructor.
     */
    public FessCrawlerThread() {
        super();
    }

        while (startedCrawlerNum < dataCrawlingThreadList.size()) {
            // Force to stop crawl
            if (systemHelper.isForceStop()) {
                for (final DataCrawlingThread crawlerThread : dataCrawlingThreadList) {
                    crawlerThread.stopCrawling();
                }
                break;
            }

            if (activeCrawlerNum < multiprocessCrawlingCount) {
                // start crawling

```

### Key Components

#### Core Engine
- **Crawler**: Main orchestrator managing crawl execution
- **CrawlerContext**: Execution context and configuration
- **CrawlerThread**: Individual crawler thread implementation

#### Client Architecture
- **HcHttpClient**: HTTP/HTTPS client using Apache HttpComponents
- **FileSystemClient**: File system access
- **FtpClient**: FTP protocol support