import com.google.common.base.Supplier;
import com.google.common.collect.ForwardingSet;
import java.util.Set;

/**
 * A subclass of `ForwardingSet` that throws `IllegalStateException` on invocation of any method
 * (except `hashCode` and `equals`) if the provided `Supplier` returns false.
 */
@ElementTypesAreNonnullByDefault
final class InvalidatableSet<E> extends ForwardingSet<E> {
  private final Supplier<Boolean> validator;

  @Override
  public Set<K> keySet() {
    Set<K> result = keySet;
    return (result == null) ? keySet = new KeySet() : result;
  }

  @WeakOuter
  private class KeySet extends ForwardingSet<K> {
    @Override
    protected Set<K> delegate() {
      return delegate.keySet();
    }

    @Override
    public void clear() {
      AbstractBiMap.this.clear();
    }

    @Override

  @Override
  public Set<K> keySet() {
    Set<K> result = keySet;
    return (result == null) ? keySet = new KeySet() : result;
  }

  @WeakOuter
  private class KeySet extends ForwardingSet<K> {
    @Override
    protected Set<K> delegate() {
      return delegate.keySet();
    }

    @Override
    public void clear() {
      AbstractBiMap.this.clear();
    }

    @Override

      this.delegate = delegate;
    }

    @Override
    protected Map<K, V> delegate() {
      return delegate;
    }

    @Override
    public Set<K> keySet() {
      return new ForwardingSet<K>() {
        @Override
        protected Set<K> delegate() {
          return delegate.keySet();
        }

        @Override
        public Iterator<K> iterator() {

    return (key == null) ? null : Maps.safeGet(delegate, key);
  }

  @Override
  ImmutableSet<Entry<K, V>> createEntrySet() {
    return ImmutableSet.unsafeDelegate(
        new ForwardingSet<Entry<K, V>>() {
          @Override
          protected Set<Entry<K, V>> delegate() {
            return delegate.entrySet();
          }

          @Override

      this.delegate = delegate;
    }

    @Override
    protected Map<K, V> delegate() {
      return delegate;
    }

    @Override
    public Set<K> keySet() {
      return new ForwardingSet<K>() {
        @Override
        protected Set<K> delegate() {
          return delegate.keySet();
        }

        @Override
        public Iterator<K> iterator() {

        cast(getKey(), value);
        return super.setValue(value);
      }
    };
  }

  @Override
  public Set<Entry<Class<? extends @NonNull B>, B>> entrySet() {
    return new ForwardingSet<Entry<Class<? extends @NonNull B>, B>>() {

      @Override
      protected Set<Entry<Class<? extends @NonNull B>, B>> delegate() {
        return MutableClassToInstanceMap.this.delegate().entrySet();
      }

          return true;
        }
      }
    }
    return false;
  }

  // Views

  @Override
  Set<E> createElementSet() {
    Set<E> delegate = countMap.keySet();
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return delegate;
      }

      @Override
      public boolean contains(@CheckForNull Object object) {

          return true;
        }
      }
    }
    return false;
  }

  // Views

  @Override
  Set<E> createElementSet() {
    Set<E> delegate = countMap.keySet();
    return new ForwardingSet<E>() {
      @Override
      protected Set<E> delegate() {
        return delegate;
      }

      @Override
      public boolean contains(@CheckForNull Object object) {

              .that(immutableCopy)
              .isIn(distinctCandidatesByAscendingSize);
        }
      }
    }
  }

  private static final class MutatedOnQuerySet<E> extends ForwardingSet<E> {
    final Iterator<ImmutableSet<E>> infiniteCandidates;

    MutatedOnQuerySet(Iterable<ImmutableSet<E>> infiniteCandidates) {
      this.infiniteCandidates = infiniteCandidates.iterator();
    }