*
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class ImmutableMapKeySet<K, V> extends IndexedImmutableSet<K> {
  private final ImmutableMap<K, V> map;

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override

 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class ImmutableMapKeySet<K, V> extends IndexedImmutableSet<K> {
  private final ImmutableMap<K, V> map;

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    return new ImmutableMapEntrySet.RegularEntrySet<>(this, entries);
  }

  @Override
  ImmutableSet<K> createKeySet() {
    return new ImmutableMapKeySet<>(this);
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  // redeclare to help optimizers with b/310253115
  @SuppressWarnings("RedundantOverride")
  @Override

    checkNotNull(action);
    entries.forEach(e -> action.accept(e.getKey(), e.getValue()));
  }

  @Override
  ImmutableSet<K> createKeySet() {
    return new ImmutableMapKeySet<>(this);
  }

  @Override
  ImmutableCollection<V> createValues() {
    return new ImmutableMapValues<>(this);
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  public ImmutableSet<K> keySet() {
    if (cachedKeySet != null) {
      return cachedKeySet;
    }
    return cachedKeySet = createKeySet();
  }

  ImmutableSet<K> createKeySet() {
    return new ImmutableMapKeySet<K, V>(this);
  }

  UnmodifiableIterator<K> keyIterator() {
    final UnmodifiableIterator<Entry<K, V>> entryIterator = entrySet().iterator();
    return new UnmodifiableIterator<K>() {
      @Override

          size(),
          Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.IMMUTABLE | Spliterator.ORDERED);
    }

    @Override
    ImmutableSet<K> createKeySet() {
      return new ImmutableMapKeySet<>(this);
    }

    @Override
    ImmutableSet<Entry<K, V>> createEntrySet() {
      class EntrySetImpl extends ImmutableMapEntrySet<K, V> {
        @Override
        ImmutableMap<K, V> map() {

    abstract UnmodifiableIterator<Entry<K, V>> entryIterator();

    @Override
    ImmutableSet<K> createKeySet() {
      return new ImmutableMapKeySet<>(this);
    }

    @Override
    ImmutableSet<Entry<K, V>> createEntrySet() {
      class EntrySetImpl extends ImmutableMapEntrySet<K, V> {
        @Override
        ImmutableMap<K, V> map() {