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;
020import com.google.errorprone.annotations.CanIgnoreReturnValue;
021import java.util.Collection;
022import java.util.Comparator;
023import java.util.Map;
024import java.util.Set;
025import java.util.SortedMap;
026import java.util.SortedSet;
027import javax.annotation.CheckForNull;
028import org.checkerframework.checker.nullness.qual.Nullable;
029
030/**
031 * A {@code SetMultimap} whose set of values for a given key are kept sorted; that is, they comprise
032 * a {@link SortedSet}. It cannot hold duplicate key-value pairs; adding a key-value pair that's
033 * already in the multimap has no effect. This interface does not specify the ordering of the
034 * multimap's keys. See the {@link Multimap} documentation for information common to all multimaps.
035 *
036 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
037 * SortedSet} of values, while {@link Multimap#entries()} returns a {@link Set} of map entries.
038 * Though the method signature doesn't say so explicitly, the map returned by {@link #asMap} has
039 * {@code SortedSet} values.
040 *
041 * <p><b>Warning:</b> As in all {@link SetMultimap}s, do not modify either a key <i>or a value</i>
042 * of a {@code SortedSetMultimap} in a way that affects its {@link Object#equals} behavior (or its
043 * position in the order of the values). Undefined behavior and bugs will result.
044 *
045 * <p>See the Guava User Guide article on <a href=
046 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap"> {@code
047 * Multimap}</a>.
048 *
049 * @author Jared Levy
050 * @since 2.0
051 */
052@GwtCompatible
053@ElementTypesAreNonnullByDefault
054public interface SortedSetMultimap<K extends @Nullable Object, V extends @Nullable Object>
055    extends SetMultimap<K, V> {
056  // Following Javadoc copied from Multimap.
057
058  /**
059   * Returns a collection view of all values associated with a key. If no mappings in the multimap
060   * have the provided key, an empty collection is returned.
061   *
062   * <p>Changes to the returned collection will update the underlying multimap, and vice versa.
063   *
064   * <p>Because a {@code SortedSetMultimap} has unique sorted values for a given key, this method
065   * returns a {@link SortedSet}, instead of the {@link java.util.Collection} specified in the
066   * {@link Multimap} interface.
067   */
068  @Override
069  SortedSet<V> get(@ParametricNullness K key);
070
071  /**
072   * Removes all values associated with a given key.
073   *
074   * <p>Because a {@code SortedSetMultimap} has unique sorted values for a given key, this method
075   * returns a {@link SortedSet}, instead of the {@link java.util.Collection} specified in the
076   * {@link Multimap} interface.
077   */
078  @CanIgnoreReturnValue
079  @Override
080  SortedSet<V> removeAll(@CheckForNull Object key);
081
082  /**
083   * Stores a collection of values with the same key, replacing any existing values for that key.
084   *
085   * <p>Because a {@code SortedSetMultimap} has unique sorted values for a given key, this method
086   * returns a {@link SortedSet}, instead of the {@link java.util.Collection} specified in the
087   * {@link Multimap} interface.
088   *
089   * <p>Any duplicates in {@code values} will be stored in the multimap once.
090   */
091  @CanIgnoreReturnValue
092  @Override
093  SortedSet<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values);
094
095  /**
096   * Returns a map view that associates each key with the corresponding values in the multimap.
097   * Changes to the returned map, such as element removal, will update the underlying multimap. The
098   * map does not support {@code setValue()} on its entries, {@code put}, or {@code putAll}.
099   *
100   * <p>When passed a key that is present in the map, {@code asMap().get(Object)} has the same
101   * behavior as {@link #get}, returning a live collection. When passed a key that is not present,
102   * however, {@code asMap().get(Object)} returns {@code null} instead of an empty collection.
103   *
104   * <p><b>Note:</b> The returned map's values are guaranteed to be of type {@link SortedSet}. To
105   * obtain this map with the more specific generic type {@code Map<K, SortedSet<V>>}, call {@link
106   * Multimaps#asMap(SortedSetMultimap)} instead. <b>However</b>, the returned map <i>itself</i> is
107   * not necessarily a {@link SortedMap}: A {@code SortedSetMultimap} must expose the <i>values</i>
108   * for a given key in sorted order, but it need not expose the <i>keys</i> in sorted order.
109   * Individual {@code SortedSetMultimap} implementations, like those built with {@link
110   * MultimapBuilder#treeKeys()}, may make additional guarantees.
111   */
112  @Override
113  Map<K, Collection<V>> asMap();
114
115  /**
116   * Returns the comparator that orders the multimap values, with {@code null} indicating that
117   * natural ordering is used.
118   */
119  @CheckForNull
120  Comparator<? super V> valueComparator();
121}