/** Returns the next entry in the access queue. */
  ReferenceEntry<K, V> getNextInAccessQueue();

  /** Sets the next entry in the access queue. */
  void setNextInAccessQueue(ReferenceEntry<K, V> next);

  /** Returns the previous entry in the access queue. */
  ReferenceEntry<K, V> getPreviousInAccessQueue();

  /** Sets the previous entry in the access queue. */

 * }
 * </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);

    /** OpenSearch client. */

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.NoSuchElementException;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * A queue which forwards all its method calls to another queue. Subclasses should override one or
 * more methods to modify the behavior of the backing queue as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

  /**
   * Constructs a new finalizable phantom reference.
   *
   * @param referent to phantom reference
   * @param queue that should finalize the referent
   */
  protected FinalizablePhantomReference(@Nullable T referent, FinalizableReferenceQueue queue) {
    super(referent, queue.queue);
    queue.cleanUp();
  }

    assertEquals(6, queue.size());
    assertEquals(8, queue.capacity());
    checkUnbounded(queue);
    checkNatural(queue);
  }

  public void testCreation_maximumSize_withContents() {
    MinMaxPriorityQueue<Integer> queue =
        rawtypeToWildcard(MinMaxPriorityQueue.maximumSize(42)).create(NUMBERS);
    assertEquals(6, queue.size());
    assertEquals(11, queue.capacity());
    assertEquals(42, queue.maximumSize);

  /**
   * Constructs a new finalizable phantom reference.
   *
   * @param referent to phantom reference
   * @param queue that should finalize the referent
   */
  protected FinalizablePhantomReference(@Nullable T referent, FinalizableReferenceQueue queue) {
    super(referent, queue.queue);
    queue.cleanUp();
  }

  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;
  }

  @CanIgnoreReturnValue
  public static Set<Feature<?>> addImpliedFeatures(Set<Feature<?>> features) {
    Queue<Feature<?>> queue = new ArrayDeque<>(features);
    while (!queue.isEmpty()) {
      Feature<?> feature = queue.remove();
      for (Feature<?> implied : feature.getImpliedFeatures()) {
        if (features.add(implied)) {
          queue.add(implied);
        }
      }
    }
    return features;
  }

  /**

        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"))

        .testForwarding(
            Queue.class,
            new Function<Queue, Queue>() {
              @Override
              public Queue apply(Queue delegate) {
                return wrap(delegate);
              }
            });
  }

  private static <T> Queue<T> wrap(Queue<T> delegate) {
    return new ForwardingQueue<T>() {
      @Override
      protected Queue<T> delegate() {
        return delegate;