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 javax.annotation.CheckForNull;
023import org.checkerframework.checker.nullness.qual.Nullable;
024
025/**
026 * A list multimap which forwards all its method calls to another list multimap. Subclasses should
027 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
028 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
029 *
030 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
031 * default} methods. Instead, it inherits their default implementations. When those implementations
032 * invoke methods, they invoke methods on the {@code ForwardingListMultimap}.
033 *
034 * @author Kurt Alfred Kluever
035 * @since 3.0
036 */
037@GwtCompatible
038@ElementTypesAreNonnullByDefault
039public abstract class ForwardingListMultimap<K extends @Nullable Object, V extends @Nullable Object>
040    extends ForwardingMultimap<K, V> implements ListMultimap<K, V> {
041
042  /** Constructor for use by subclasses. */
043  protected ForwardingListMultimap() {}
044
045  @Override
046  protected abstract ListMultimap<K, V> delegate();
047
048  @Override
049  public List<V> get(@ParametricNullness K key) {
050    return delegate().get(key);
051  }
052
053  @CanIgnoreReturnValue
054  @Override
055  public List<V> removeAll(@CheckForNull Object key) {
056    return delegate().removeAll(key);
057  }
058
059  @CanIgnoreReturnValue
060  @Override
061  public List<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {
062    return delegate().replaceValues(key, values);
063  }
064}