}

  private static Set<Feature<?>> computeKeySetFeatures(Set<Feature<?>> mapFeatures) {
    Set<Feature<?>> keySetFeatures = computeCommonDerivedCollectionFeatures(mapFeatures);

    // TODO(lowasser): make this trigger only if the map is a submap
    // currently, the KeySetGenerator won't work properly for a subset of a keyset of a submap
    keySetFeatures.add(CollectionFeature.SUBSET_VIEW);

 * superclasses, and all interfaces implemented by superclasses.
 *
 * <p>When {@code post} is called, all registered subscribers for an event are run in sequence, so
 * subscribers should be reasonably quick. If an event may trigger an extended process (such as a
 * database load), spawn a thread or queue it for later. (For a convenient way to do this, use an
 * {@link AsyncEventBus}.)
 *
 * <h2>Subscriber Methods</h2>
 *

     *   null _failure message_)
     *
     * That combination upsets NullPointerTester, which wants any call that passes null for a
     * non-@Nullable parameter to trigger a NullPointerException.
     *
     * (We still define this empty method to keep PackageSanityTests from generating its own
     * automated nullness tests, which would fail.)
     */
  }

    awaitTimedWaiting(waiter);
    service.shutdown();
    Uninterruptibles.joinUninterruptibly(waiter, 10, TimeUnit.SECONDS);
    if (waiter.isAlive()) {
      waiter.interrupt();
      fail("awaitTermination failed to trigger after shutdown()");
    }
  }

  /** Wait for the given thread to reach the {@link State#TIMED_WAITING} thread state. */
  void awaitTimedWaiting(Thread thread) {
    while (true) {

 * function doing a good job of distributing the elements to the buckets to a distribution not far
 * from uniform), and amortized since some operations can trigger a hash table resize.
 *
 * <p>Unlike {@code java.util.HashMap}, iteration is only proportional to the actual {@code size()},
 * which is optimal, and <i>not</i> the size of the internal hashtable, which could be much larger

    this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {
    return delegate.hashCode();
  }

  private void validate() {

   *
   * <p>Currently, this method is invoked while holding a lock. If an implementation of this method
   * blocks, it can prevent this service from changing state. If you need to performing a blocking
   * operation in order to trigger shutdown, consider instead registering a listener and
   * implementing {@code stopping}. Note, however, that {@code stopping} does not run at exactly the
   * same times as {@code triggerShutdown}.
   */

  }

  private static Set<Feature<?>> computeKeySetFeatures(Set<Feature<?>> mapFeatures) {
    Set<Feature<?>> keySetFeatures = computeCommonDerivedCollectionFeatures(mapFeatures);

    // TODO(lowasser): make this trigger only if the map is a submap
    // currently, the KeySetGenerator won't work properly for a subset of a keyset of a submap
    keySetFeatures.add(CollectionFeature.SUBSET_VIEW);

 * function doing a good job of distributing the elements to the buckets to a distribution not far
 * from uniform), and amortized since some operations can trigger a hash table resize.
 *
 * <p>As compared with {@link java.util.LinkedHashMap}, this structure places significantly reduced
 * load on the garbage collector by only using a constant number of internal objects.
 *

   * map built by MapMaker) no longer has a strong reference to this object, the garbage collector
   * will reclaim it and enqueue the phantom reference. The enqueued reference will trigger the
   * Finalizer to stop.
   *
   * If this library is loaded in the system class loader, FinalizableReferenceQueue can load
   * Finalizer directly with no problems.
   *