001/*
002 * Copyright (C) 2007 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;
020
021import java.util.Collection;
022import java.util.List;
023import java.util.Map;
024
025import javax.annotation.Nullable;
026
027/**
028 * A {@code Multimap} that can hold duplicate key-value pairs and that maintains
029 * the insertion ordering of values for a given key. See the {@link Multimap}
030 * documentation for information common to all multimaps.
031 *
032 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods
033 * each return a {@link List} of values. Though the method signature doesn't say
034 * so explicitly, the map returned by {@link #asMap} has {@code List} values.
035 *
036 * <p>See the Guava User Guide article on <a href=
037 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap">
038 * {@code Multimap}</a>.
039 *
040 * @author Jared Levy
041 * @since 2.0
042 */
043@GwtCompatible
044public interface ListMultimap<K, V> extends Multimap<K, V> {
045  /**
046   * {@inheritDoc}
047   *
048   * <p>Because the values for a given key may have duplicates and follow the
049   * insertion ordering, this method returns a {@link List}, instead of the
050   * {@link java.util.Collection} specified in the {@link Multimap} interface.
051   */
052  @Override
053  List<V> get(@Nullable K key);
054
055  /**
056   * {@inheritDoc}
057   *
058   * <p>Because the values for a given key may have duplicates and follow the
059   * insertion ordering, this method returns a {@link List}, instead of the
060   * {@link java.util.Collection} specified in the {@link Multimap} interface.
061   */
062  @Override
063  List<V> removeAll(@Nullable Object key);
064
065  /**
066   * {@inheritDoc}
067   *
068   * <p>Because the values for a given key may have duplicates and follow the
069   * insertion ordering, this method returns a {@link List}, instead of the
070   * {@link java.util.Collection} specified in the {@link Multimap} interface.
071   */
072  @Override
073  List<V> replaceValues(K key, Iterable<? extends V> values);
074
075  /**
076   * {@inheritDoc}
077   *
078   * <p><b>Note:</b> The returned map's values are guaranteed to be of type
079   * {@link List}. To obtain this map with the more specific generic type
080   * {@code Map<K, List<V>>}, call {@link Multimaps#asMap(ListMultimap)}
081   * instead.
082   */
083  @Override
084  Map<K, Collection<V>> asMap();
085
086  /**
087   * Compares the specified object to this multimap for equality.
088   *
089   * <p>Two {@code ListMultimap} instances are equal if, for each key, they
090   * contain the same values in the same order. If the value orderings disagree,
091   * the multimaps will not be considered equal.
092   *
093   * <p>An empty {@code ListMultimap} is equal to any other empty {@code
094   * Multimap}, including an empty {@code SetMultimap}.
095   */
096  @Override
097  boolean equals(@Nullable Object obj);
098}