@GwtIncompatible // not worth using in GWT for now
final class CompactLinkedHashMap<K extends @Nullable Object, V extends @Nullable Object>
    extends CompactHashMap<K, V> {
  // TODO(lowasser): implement removeEldestEntry so this can be used as a drop-in replacement

  /** Creates an empty {@code CompactLinkedHashMap} instance. */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      CompactLinkedHashMap<K, V> create() {

   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying

   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying

  public E last() {
    return delegate.last();
  }

  @Override
  public @Nullable E lower(E e) {
    return delegate.lower(checkValid(e));
  }

  @Override
  public @Nullable E pollFirst() {
    return delegate.pollFirst();
  }

  @Override
  public @Nullable E pollLast() {
    return delegate.pollLast();
  }

  @Override
  public boolean remove(Object object) {

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;

    this.forward = forward;
  }

  @Override
  public int count(@Nullable Object element) {
    return forward.count(element);
  }

  @Override
  public @Nullable Entry<E> firstEntry() {
    return forward.lastEntry();
  }

  @Override
  public @Nullable Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {

   * @return the replacement string, or {@code null} if no escaping was needed
   */
  public static @Nullable String computeReplacement(UnicodeEscaper escaper, int cp) {
    return stringOrNull(escaper.escape(cp));
  }

  private static @Nullable String stringOrNull(char @Nullable [] in) {
    return (in == null) ? null : new String(in);
  }

  }

  @Override
  public @Nullable E lower(E element) {
    return forward.higher(element);
  }

  @Override
  public @Nullable E floor(E element) {
    return forward.ceiling(element);
  }

  @Override
  public @Nullable E ceiling(E element) {
    return forward.floor(element);
  }

  @Override
  public @Nullable E higher(E element) {
    return forward.lower(element);
  }

   *
   * @since 19.0
   */
  public static <K, V> RemovalNotification<K, V> create(
      @Nullable K key, @Nullable V value, RemovalCause cause) {
    return new RemovalNotification<>(key, value, cause);
  }

  private RemovalNotification(@Nullable K key, @Nullable V value, RemovalCause cause) {
    super(key, value);
    this.cause = checkNotNull(cause);
  }