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