this.delegate = null
      delegate.onFailure(webSocket, t, response)
    } else {
      events.add(Failure(t, response))
    }
  }

  private fun nextEvent(): Any =
    events.poll(10, TimeUnit.SECONDS)
      ?: throw AssertionError("Timed out waiting for event.")

  fun assertTextMessage(payload: String?) {
    assertThat(nextEvent()).isEqualTo(Message(string = payload))
  }

   */
  protected void startUp() throws Exception {}

  /**
   * Run the service. This method is invoked on the execution thread. Implementations must respond
   * to stop requests. You could poll for lifecycle changes in a work loop:
   *
   * <pre>
   *   public void run() {
   *     while ({@link #isRunning()}) {
   *       // perform a unit of work
   *     }
   *   }
   * </pre>
   *

 * to perform its tasks.
 * </p>
 *
 * <p>
 * The crawling process involves the following steps:
 * </p>
 * <ol>
 *   <li>Fetching a URL from the queue using {@link UrlQueueService#poll(String)}.</li>
 *   <li>Checking if the URL is valid using {@link #isValid(UrlQueue)}.</li>
 *   <li>Accessing the content using a {@link CrawlerClient} obtained from {@link CrawlerClientFactory}.</li>

            UrlQueue urlQueue;
            while ((urlQueue = urlQueueService.poll(sessionId1)) != null) {
                assertTrue(urlQueue.getUrl().startsWith(url1));
            }
            while ((urlQueue = urlQueueService.poll(sessionId2)) != null) {
                assertTrue(urlQueue.getUrl().startsWith(url2));
            }

    synchronized(this@RealWebSocket) {
      if (failed) {
        return false // Failed web socket.
      }

      writer = this.writer
      pong = pongQueue.poll()
      if (pong == null) {
        messageOrClose = messageAndCloseQueue.poll()
        if (messageOrClose is Close) {
          receivedCloseCode = this.receivedCloseCode
          receivedCloseReason = this.receivedCloseReason

          .map { sampleValues[it.type] ?: error("no sample value for ${it.type}") }
          .toTypedArray()

      method.invoke(solo.eventListener, *args)
      method.invoke(composite, *args)

      val expectedEvent = solo.takeEvent()
      assertThat(solo.eventSequence).isEmpty()

      assertThat(left.takeEvent()::class).isEqualTo(expectedEvent::class)
      assertThat(left.eventSequence).isEmpty()

   */
  protected void startUp() throws Exception {}

  /**
   * Run the service. This method is invoked on the execution thread. Implementations must respond
   * to stop requests. You could poll for lifecycle changes in a work loop:
   *
   * <pre>
   *   public void run() {
   *     while ({@link #isRunning()}) {
   *       // perform a unit of work
   *     }
   *   }
   * </pre>
   *

int maxDepth = -1               // Max depth (-1 = unlimited)
long maxAccessCount = 0         // Max URLs (0 = unlimited)
```

### CrawlerThread (`CrawlerThread.java`)

Worker thread for crawling.

**Flow**: Poll URL → Validate → Get client → Delay → Check last-modified → Execute → Process → Extract children → Queue children → Delay

### CrawlerClientFactory

Pattern-based client selection using `LinkedHashMap<Pattern, CrawlerClient>`.

    $ mvn package
    $ mvn rpm:rpm   # Paquete .rpm
    $ mvn jdeb:jdeb # Paquete .deb

### Generar Código Fuente

    $ mvn dbflute:download # (comando ejecutado una sola vez)
    $ mvn dbflute:freegen
    $ mvn license:format

### Pruebas de Integración

Inicia el servidor Fess y ejecuta el siguiente comando:

    }

    @Override
    public synchronized Map<String, Object> read() {
        while (!isFinished.get() && queue.isEmpty()) {
            addDocumentToQueue();
        }

        return queue.poll();
    }

    @Override
    public void close() {
        isFinished.set(true);
        queue.clear();
    }

    /**
     * Sets the scroll size.
     * @param scrollSize The scroll size.