return size() == 0;
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return get(key) != null;
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return values().contains(value);
  }

  // Overriding to mark it Nullable
  @Override
  public abstract @Nullable V get(@Nullable Object key);

  /**

import com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import java.util.Comparator;
import org.jspecify.annotations.Nullable;

/** An ordering for a pre-existing comparator. */
@GwtCompatible
final class ComparatorOrdering<T extends @Nullable Object> extends Ordering<T>
    implements Serializable {
  final Comparator<T> comparator;

  ComparatorOrdering(Comparator<T> comparator) {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import java.util.Collection;
import org.jspecify.annotations.Nullable;

/**
 * A GWT-only class only used by GWT emulations. It is used to consolidate the definitions of method
 * delegation to save code size.
 *
 * @author Hayward Chan
 */

import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link AbstractFuture} that use a non-{@link TrustedFuture} for {@link
 * AbstractFuture#setFuture} calls.
 */
@GwtCompatible
@NullUnmarked
public class UntrustedInputFutureTest extends AbstractAbstractFutureTest {
  @Override
  AbstractFuture<@Nullable Integer> newDelegate() {

 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap">{@code Multimap}</a>.
 *
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public interface SetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends Multimap<K, V> {
  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a

 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
public interface BiMap<K extends @Nullable Object, V extends @Nullable Object> extends Map<K, V> {
  // Modification Operations

  /**
   * {@inheritDoc}
   *
   * @throws IllegalArgumentException if the given value is already bound to a different key in this

 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap">{@code Multimap}</a>.
 *
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible
public interface SetMultimap<K extends @Nullable Object, V extends @Nullable Object>
    extends Multimap<K, V> {
  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a

   * a good policy, especially because, in order for the test to pass, the
   * parameter must be misleadingly annotated as @Nullable. I suspect that
   * we'll want to remove @Nullable, add an eager checkNotNull, and loosen up
   * testRemove_nullAllowed.
   */
  @CanIgnoreReturnValue
  @Override
  public int remove(@Nullable Object element, int occurrences) {
    if (occurrences == 0) {
      return count(element);
    }

   * as well.
   */
  @Override
  public abstract ImmutableMap<R, Map<C, V>> rowMap();

  @Override
  public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey) {
    return get(rowKey, columnKey) != null;
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    return values().contains(value);
  }

  /**
   * Guaranteed to throw an exception and leave the table unmodified.

  // the same values as `elements` in hashed positions (plus nulls)
  @VisibleForTesting final transient @Nullable Object[] table;
  // 'and' with an int to get a valid table index.
  private final transient int mask;

  RegularImmutableSet(Object[] elements, int hashCode, @Nullable Object[] table, int mask) {
    this.elements = elements;
    this.hashCode = hashCode;
    this.table = table;
    this.mask = mask;