import java.io.Serializable;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * An ordering that orders elements by applying an order to the result of a function on those
 * elements.
 */
@GwtCompatible
final class ByFunctionOrdering<F extends @Nullable Object, T extends @Nullable Object>
    extends Ordering<F> implements Serializable {
  final Function<F, ? extends T> function;

import org.jspecify.annotations.Nullable;

/**
 * Equivalence applied on functional result.
 *
 * @author Bob Lee
 * @since 10.0
 */
@GwtCompatible
final class FunctionalEquivalence<F, T> extends Equivalence<F> implements Serializable {

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

  private final Function<? super F, ? extends @Nullable T> function;

  public @Nullable K floorKey(K key) {
    return keyOrNull(floorEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> ceilingEntry(K key) {
    return tailMap(key, true).firstEntry();
  }

  @Override
  public @Nullable K ceilingKey(K key) {
    return keyOrNull(ceilingEntry(key));
  }

  @Override
  public @Nullable Entry<K, V> higherEntry(K key) {

 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code

 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code

 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code

 *       String}.
 * </ul>
 *
 * This is the same behavior as type-variable usages have to Kotlin and to the Checker Framework.
 * Contrast the method above to:
 *
 * <ul>
 *   <li>methods whose return type is a type variable but which can never return {@code null},
 *       typically because the type forbids nullable type arguments: For example, {@code

      List<@Nullable String> listWithNulls = asList("a", null, "b");
      assertThrows(NullPointerException.class, () -> builder.addAll((List<String>) listWithNulls));
    }

    {
      ImmutableMultiset.Builder<String> builder = ImmutableMultiset.builder();
      Multiset<@Nullable String> multisetWithNull =
          LinkedHashMultiset.create(Arrays.<@Nullable String>asList("a", null, "b"));

 * "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

              }

              @Override
              public boolean equals(@Nullable Object o) {
                return map.equals(o);
              }

              @Override
              public String toString() {
                return map.toString();
              }

              @Override
              public @Nullable String remove(Object key) {
                return map.remove(key);
              }