private final BlockingQueue<HttpUrl> queue;
  private final ConcurrentHashMap<String, AtomicInteger> hostnames = new ConcurrentHashMap<>();
  private final int hostLimit;

  public Crawler(OkHttpClient client, int queueLimit, int hostLimit) {
    this.client = client;
    this.queue = new LinkedBlockingQueue<>(queueLimit);
    this.hostLimit = hostLimit;
  }

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Strings;
import java.util.List;
import java.util.Queue;
import org.jspecify.annotations.NullMarked;

/**
 * Create queue of strings for tests.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public abstract class TestStringQueueGenerator implements TestQueueGenerator<String> {
  @Override

            errorsField.setAccessible(true);
            Queue<String> errors = (Queue<String>) errorsField.get(null);
            errors.clear();
        } catch (Exception e) {
            // Ignore if field doesn't exist
        }

        // Add some errors to the queue
        Crawler.addError("Error 1");
        Crawler.addError("Error 2");

import org.opensearch.index.query.functionscore.RandomScoreFunctionBuilder;
import org.opensearch.search.sort.SortBuilders;
import org.opensearch.search.sort.SortOrder;

/**
 * Fess-specific URL queue service that extends OpenSearch URL queue functionality.
 * This service provides customized URL fetching strategies including sequential and random ordering
 * based on crawling configuration parameters.
 */

            waitingCoordinatorInterrupted = false
            throw InterruptedException()
          }
        }

        override fun <T> decorate(queue: BlockingQueue<T>) = TaskFakerBlockingQueue(queue)
      },
      logger = logger,
    )

  /** Runs all tasks that are ready. Used by the test thread only. */
  fun runTasks() {
    advanceUntil(nanoTime)
  }

    private final Queue<T> queue;

    UnIterableQueue(Queue<T> queue) {
      this.queue = queue;
    }

    @Override
    public Iterator<T> iterator() {
      throw new UnsupportedOperationException();
    }

    @Override
    protected Queue<T> delegate() {
      return queue;
    }
  }

  public void testIndexOf_empty() {

  }

  private void enqueueHelper(Event<L> event, Object label) {
    checkNotNull(event, "event");
    checkNotNull(label, "label");
    synchronized (listeners) {
      for (PerListenerQueue<L> queue : listeners) {
        queue.add(event, label);
      }
    }
  }

  /**
   * Dispatches all events enqueued prior to this call, serially and in order, for every listener.
   *

    #                                                                                Quill
    #                                                                                =====
    # /- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    # o quillDataSourceName: (NotRequired - Default null)
    #  The data source name of Quill(CSharp Seasar).
    #
    # @QuillOnly
    #; quillDataSourceName = ExampleDB

    private final Queue<T> queue;

    UnIterableQueue(Queue<T> queue) {
      this.queue = queue;
    }

    @Override
    public Iterator<T> iterator() {
      throw new UnsupportedOperationException();
    }

    @Override
    protected Queue<T> delegate() {
      return queue;
    }
  }

  public void testIndexOf_empty() {

    /**
     * Gets the delay time in milliseconds when there are no URLs in the queue.
     *
     * @return the delay time in milliseconds when no URLs are available
     */
    public long getDelayMillisAtNoUrlInQueue() {
        return delayMillisAtNoUrlInQueue;
    }

    /**
     * Sets the delay time in milliseconds when there are no URLs in the queue.
     *