* as well as to handle state changes in a thread-safe manner. The current state of the future
     * is held in the Sync state, and the lock is released whenever the state changes to {@link
     * #COMPLETED}, {@link #CANCELLED}, or {@link #INTERRUPTED}
     *
     * <p>To avoid races between threads doing release and acquire, we transition to the final state

      for (Segment<?, ?> segment : map.segments) {
        drainRecencyQueue(segment);
      }
    }
  }

  static void drainRecencyQueue(Segment<?, ?> segment) {
    segment.lock();
    try {
      segment.cleanUp();
    } finally {
      segment.unlock();
    }
  }

  static void drainReferenceQueues(Cache<?, ?> cache) {
    if (hasLocalCache(cache)) {

 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/CollectionHelpersExplained#peekingiterator">{@code
 * PeekingIterator}</a>.
 *
 * @author Mick Killianey
 * @since 2.0
 */
@DoNotMock("Use Iterators.peekingIterator")
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface PeekingIterator<E extends @Nullable Object> extends Iterator<E> {
  /**

    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));
      return delegate.iterator();
    }

    @Override
    public int size() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.size();

      return Longs.fromBytes(
          bytes[15], bytes[14], bytes[13], bytes[12], bytes[11], bytes[10], bytes[9], bytes[8]);
    }
  };

  /**
   * Models a lock-free array of bits.
   *
   * <p>We use this instead of java.util.BitSet because we need access to the array of longs and we
   * need compare-and-swap.
   */
  static final class LockFreeBitArray {

     *
     * <ol>
     *   <li>Update the {@link #servicesByState()}
     *   <li>Update the {@link #startupTimers}
     *   <li>Based on the new state queue listeners to run
     *   <li>Run the listeners (outside of the lock)
     * </ol>
     */
    void transitionService(final Service service, State from, State to) {
      checkNotNull(service);
      checkArgument(from != to);
      monitor.enter();
      try {

 * generated today may <i>not</i> be readable by a binary that was compiled 6 months ago).
 *
 * <p>As of Guava 23.0, this class is thread-safe and lock-free. It internally uses atomics and
 * compare-and-swap to ensure correctness when multiple threads are used to access it.
 *
 * @param <T> the type of instances that the {@code BloomFilter} accepts
 * @author Dimitris Andreou

    final Lock lock;

    LockingThread(Lock lock) {
      this.lock = lock;
    }

    @Override
    public void run() {
      lock.lock();
      try {
        locked.countDown();
        finishLatch.await(1, TimeUnit.MINUTES);
      } catch (InterruptedException e) {
        fail(e.toString());
      } finally {
        lock.unlock();
      }
    }

 * </ul>
 *
 * The last point is subtle. Often the observable object will be managing its own internal state
 * using a lock, however it is dangerous to dispatch listeners while holding a lock because they
 * might run on the {@code directExecutor()} or be otherwise re-entrant (call back into your
 * object). So it is important to not call {@link #dispatch} while holding any locks. This is why

    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));
      return delegate.iterator();
    }

    @Override
    public int size() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.size();