E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

  abstract Iterator<Entry<E>> descendingEntryIterator();

  static <K, V> CacheLoader<K, V> errorLoader(final Error e) {
    checkNotNull(e);
    return new CacheLoader<K, V>() {
      @Override
      public V load(K key) {
        throw e;
      }
    };
  }

  /** Returns a {@link CacheLoader} that throws the given exception for every request. */
  static <K, V> CacheLoader<K, V> exceptionLoader(final Exception e) {
    checkNotNull(e);
    return new CacheLoader<K, V>() {
      @Override

   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0
   */
  public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
    checkNotNull(enumClass);
    checkNotNull(value);
    return Platform.getEnumIfPresent(enumClass, value);
  }

  @GwtIncompatible // java.lang.ref.WeakReference

  final Multimap<K, V> unfiltered;
  final Predicate<? super K> keyPredicate;

  FilteredKeyMultimap(Multimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    this.unfiltered = checkNotNull(unfiltered);
    this.keyPredicate = checkNotNull(keyPredicate);
  }

  @Override
  public Multimap<K, V> unfiltered() {
    return unfiltered;
  }

  @Override
  public Predicate<? super Entry<K, V>> entryPredicate() {

      super(listenerExecutor);
      this.callable = checkNotNull(callable);
    }

    @Override
    ListenableFuture<V> runInterruptibly() throws Exception {
      ListenableFuture<V> result = callable.call();
      return checkNotNull(
          result,
          "AsyncCallable.call returned null instead of a Future. "

  final Multimap<K, V> unfiltered;
  final Predicate<? super K> keyPredicate;

  FilteredKeyMultimap(Multimap<K, V> unfiltered, Predicate<? super K> keyPredicate) {
    this.unfiltered = checkNotNull(unfiltered);
    this.keyPredicate = checkNotNull(keyPredicate);
  }

  @Override
  public Multimap<K, V> unfiltered() {
    return unfiltered;
  }

  @Override
  public Predicate<? super Entry<K, V>> entryPredicate() {

@ElementTypesAreNonnullByDefault
final class ImmutableEnumMap<K, V> extends ForwardingImmutableMap<K, V> {
  static <K, V> ImmutableMap<K, V> asImmutable(Map<K, V> map) {
    for (Entry<K, V> entry : checkNotNull(map).entrySet()) {
      checkNotNull(entry.getKey());
      checkNotNull(entry.getValue());
    }
    return new ImmutableEnumMap<K, V>(map);
  }

  private ImmutableEnumMap(Map<? extends K, ? extends V> delegate) {
    super(delegate);
  }

    TrustedFutureInterruptibleAsyncTask(AsyncCallable<V> callable) {
      this.callable = checkNotNull(callable);
    }

    @Override
    final boolean isDone() {
      return TrustedListenableFutureTask.this.isDone();
    }

    @Override
    ListenableFuture<V> runInterruptibly() throws Exception {
      return checkNotNull(
          callable.call(),
          "AsyncCallable.call returned null instead of a Future. "

  public static final <E> InvalidatableSet<E> of(
      Set<E> delegate, Supplier<Boolean> validator, Supplier<String> errorMessage) {
    return new InvalidatableSet<>(
        checkNotNull(delegate), checkNotNull(validator), checkNotNull(errorMessage));
  }

  @Override
  protected Set<E> delegate() {
    validate();
    return delegate;
  }

  private InvalidatableSet(

  @CanIgnoreReturnValue
  public CharEscaperBuilder addEscape(char c, String r) {
    map.put(c, checkNotNull(r));
    if (c > max) {
      max = c;
    }
    return this;
  }

  /** Add multiple mappings at once for a particular index. */
  @CanIgnoreReturnValue
  public CharEscaperBuilder addEscapes(char[] cs, String r) {
    checkNotNull(r);
    for (char c : cs) {
      addEscape(c, r);
    }
    return this;
  }