@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;
  }

  /**

        .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;

 * index names, shard counts, and replica counts for queue, data, and filter indices.
 */
public class FessCrawlerConfig extends OpenSearchCrawlerConfig {

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

    /**
     * Gets the name of the queue index for the crawler.
     *
     * @return the queue index name
     */
    @Override

import java.lang.reflect.Method;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.LinkedList;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;

#### Per-Connection Locks

Each connection has its own lock. The connections in the pool are all in a `ConcurrentLinkedQueue`. Due to data races, iterators of this queue may return removed connections. Callers must check the connection's `noNewExchanges` property before using connections from the pool.

The connection lock is never held while doing I/O (even closing a socket) to prevent contention.

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

   * {@link Iterators#consumingIterator(Iterator)}.
   *
   * <p>Note: If {@code iterable} is a {@link Queue}, the returned iterable will instead use {@link
   * Queue#isEmpty} and {@link Queue#remove()}, since {@link Queue}'s iteration order is undefined.
   * Calling {@link Iterator#hasNext()} on a generated iterator from the returned iterable may cause

  /** 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. */

     */
    protected String charsetName = CoreLibConstants.UTF_8;

    /**
     * The queue of ciphers for encryption.
     */
    protected Queue<Cipher> encryptoQueue = new ConcurrentLinkedQueue<>();

    /**
     * The queue of ciphers for decryption.
     */
    protected Queue<Cipher> decryptoQueue = new ConcurrentLinkedQueue<>();

    /**
     * Encrypts the given data.
     *

  @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;
  }

  /**