001/*
002 * Copyright (C) 2010 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect;
018
019import com.google.common.annotations.GwtCompatible;
020import com.google.errorprone.annotations.CanIgnoreReturnValue;
021import java.util.List;
022import org.jspecify.annotations.Nullable;
023
024/**
025 * A list multimap which forwards all its method calls to another list multimap. Subclasses should
026 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
027 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
028 *
029 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
030 * default} methods. Instead, it inherits their default implementations. When those implementations
031 * invoke methods, they invoke methods on the {@code ForwardingListMultimap}.
032 *
033 * @author Kurt Alfred Kluever
034 * @since 3.0
035 */
036@GwtCompatible
037public abstract class ForwardingListMultimap<K extends @Nullable Object, V extends @Nullable Object>
038    extends ForwardingMultimap<K, V> implements ListMultimap<K, V> {
039
040  /** Constructor for use by subclasses. */
041  protected ForwardingListMultimap() {}
042
043  @Override
044  protected abstract ListMultimap<K, V> delegate();
045
046  @Override
047  public List<V> get(@ParametricNullness K key) {
048    return delegate().get(key);
049  }
050
051  @CanIgnoreReturnValue
052  @Override
053  public List<V> removeAll(@Nullable Object key) {
054    return delegate().removeAll(key);
055  }
056
057  @CanIgnoreReturnValue
058  @Override
059  public List<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
060    return delegate().replaceValues(key, values);
061  }
062}