}

  final Set<K> unmodifiableKeySet() {
    return new AbstractSet<K>() {
      @Override
      public UnmodifiableIterator<K> iterator() {
        Iterator<Entry<K, V>> entryIterator = backingMap.entrySet().iterator();

        return new UnmodifiableIterator<K>() {
          @Override
          public boolean hasNext() {
            return entryIterator.hasNext();
          }

    this.map = map;
  }

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

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

      @Override
      public boolean hasNext() {
        return entryItr.hasNext();
      }

      @Override

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterators;
import com.google.common.collect.UnmodifiableIterator;
import java.util.AbstractSet;
import java.util.Map;
import org.jspecify.annotations.Nullable;

/**
 * A class to represent the set of edges connecting an (implicit) origin node to a target node.
 *

  @Override
  public boolean contains(@Nullable Object object) {
    return forward.contains(object);
  }

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

  @Override
  public UnmodifiableIterator<E> iterator() {
    return forward.descendingIterator();
  }

  @Override
  ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive) {
    return forward.tailSet(toElement, inclusive).descendingSet();

/**
 * Tests for {@link UnmodifiableIterator}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class UnmodifiableIteratorTest extends TestCase {

  @SuppressWarnings("DoNotCall")
  public void testRemove() {
    String[] array = {"a", "b", "c"};

    Iterator<String> iterator =
        new UnmodifiableIterator<String>() {
          int i;

          @Override

import com.google.common.base.Function;
import com.google.common.collect.AbstractIterator;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterators;
import com.google.common.collect.UnmodifiableIterator;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;

   * overrides it.
   */
  abstract ImmutableSet<K> createKeySet();

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

      @Override

  ForwardingImmutableSet(Set<E> delegate) {
    // TODO(cpovirk): are we over-wrapping?
    this.delegate = Collections.unmodifiableSet(delegate);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override
  public boolean contains(@Nullable Object object) {
    return object != null && delegate.contains(object);
  }

  @Override

  private ImmutableEnumSet(EnumSet<E> delegate) {
    this.delegate = delegate;
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override
  public Spliterator<E> spliterator() {
    return delegate.spliterator();
  }

  @Override

  static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED;

  ImmutableCollection() {}

  @Override
  public abstract UnmodifiableIterator<E> iterator();

  @Override
  public boolean contains(@Nullable Object object) {
    return object != null && super.contains(object);
  }

  @Override
  public final boolean add(E e) {