* entries may be counted in {@link Cache#size}, but will never be visible to read or write
 * operations.
 *
 * <p>Certain cache configurations will result in the accrual of periodic maintenance tasks which
 * will be performed during write operations, or during occasional read operations in the absence of

  public CacheStats stats() {
    return delegate().stats();
  }

  @Override
  public ConcurrentMap<K, V> asMap() {
    return delegate().asMap();
  }

  @Override
  public void cleanUp() {
    delegate().cleanUp();
  }

  /**
   * A simplified version of {@link ForwardingCache} where subclasses can pass in an already
   * constructed {@link Cache} as the delegate.
   *
   * @since 10.0
   */

  public CacheStats stats() {
    return delegate().stats();
  }

  @Override
  public ConcurrentMap<K, V> asMap() {
    return delegate().asMap();
  }

  @Override
  public void cleanUp() {
    delegate().cleanUp();
  }

  /**
   * A simplified version of {@link ForwardingCache} where subclasses can pass in an already
   * constructed {@link Cache} as the delegate.
   *
   * @since 10.0
   */

  @SuppressWarnings("InfiniteLoopStatement")
  @Override
  public void run() {
    while (true) {
      try {
        if (!cleanUp(queue.remove())) {
          break;
        }
      } catch (InterruptedException e) {
        // ignore
      }
    }
  }

  /**
   * Cleans up the given reference and any other references already in the queue. Catches and logs
   * all throwables.
   *

          Level.INFO,
          "Failed to start reference finalizer thread."
              + " Reference cleanup will only occur when new references are created.",
          t);
    }

    this.threadStarted = threadStarted;
  }

  @Override
  public void close() {
    frqRef.enqueue();
    cleanUp();
  }

  /**
   * Repeatedly dequeues references from the queue and invokes {@link

          Level.INFO,
          "Failed to start reference finalizer thread."
              + " Reference cleanup will only occur when new references are created.",
          t);
    }

    this.threadStarted = threadStarted;
  }

  @Override
  public void close() {
    frqRef.enqueue();
    cleanUp();
  }

  /**
   * Repeatedly dequeues references from the queue and invokes {@link

 * implemented in terms of {@link #getIfPresent}; {@link #putAll} is implemented in terms of {@link
 * #put}, {@link #invalidateAll(Iterable)} is implemented in terms of {@link #invalidate}. The
 * method {@link #cleanUp} is a no-op. All other methods throw an {@link
 * UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test
  // may put a thread into an uninterruptible operation intentionally, so there is no other way to
  // clean up these threads.
  @SuppressWarnings("deprecation")
  @Override
  public void tearDown() throws Exception {
    stop();
    join();

    if (uncaughtThrowable != null) {
      throw (AssertionFailedError)

 *
 * <p>A call to any of the <i>enter</i> methods with <b>void</b> return type should always be
 * followed immediately by a <i>try/finally</i> block to ensure that the current thread leaves the
 * monitor cleanly:
 *
 * <pre>{@code
 * monitor.enter();
 * try {
 *   // do things while occupying the monitor
 * } finally {
 *   monitor.leave();
 * }
 * }</pre>
 *

were learning to draw, you know--'

  `What did they draw?' said Alice, quite forgetting her promise.

  `Treacle,' said the Dormouse, without considering at all this
time.

  `I want a clean cup,' interrupted the Hatter:  `let's all move
one place on.'

  He moved on as he spoke, and the Dormouse followed him:  the
March Hare moved into the Dormouse's place, and Alice rather