1 /* 2 * Copyright (C) 2007 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect; 18 19 import com.google.common.annotations.GwtCompatible; 20 21 import java.util.Collection; 22 import java.util.Map; 23 import java.util.Set; 24 25 import javax.annotation.Nullable; 26 27 /** 28 * Basic implementation of the {@link SetMultimap} interface. It's a wrapper 29 * around {@link AbstractMapBasedMultimap} that converts the returned collections into 30 * {@code Sets}. The {@link #createCollection} method must return a {@code Set}. 31 * 32 * @author Jared Levy 33 */ 34 @GwtCompatible 35 abstract class AbstractSetMultimap<K, V> 36 extends AbstractMapBasedMultimap<K, V> implements SetMultimap<K, V> { 37 /** 38 * Creates a new multimap that uses the provided map. 39 * 40 * @param map place to store the mapping from each key to its corresponding 41 * values 42 */ 43 protected AbstractSetMultimap(Map<K, Collection<V>> map) { 44 super(map); 45 } 46 47 @Override abstract Set<V> createCollection(); 48 49 @Override Set<V> createUnmodifiableEmptyCollection() { 50 return ImmutableSet.of(); 51 } 52 53 // Following Javadoc copied from SetMultimap. 54 55 /** 56 * {@inheritDoc} 57 * 58 * <p>Because a {@code SetMultimap} has unique values for a given key, this 59 * method returns a {@link Set}, instead of the {@link Collection} specified 60 * in the {@link Multimap} interface. 61 */ 62 @Override public Set<V> get(@Nullable K key) { 63 return (Set<V>) super.get(key); 64 } 65 66 /** 67 * {@inheritDoc} 68 * 69 * <p>Because a {@code SetMultimap} has unique values for a given key, this 70 * method returns a {@link Set}, instead of the {@link Collection} specified 71 * in the {@link Multimap} interface. 72 */ 73 @Override public Set<Map.Entry<K, V>> entries() { 74 return (Set<Map.Entry<K, V>>) super.entries(); 75 } 76 77 /** 78 * {@inheritDoc} 79 * 80 * <p>Because a {@code SetMultimap} has unique values for a given key, this 81 * method returns a {@link Set}, instead of the {@link Collection} specified 82 * in the {@link Multimap} interface. 83 */ 84 @Override public Set<V> removeAll(@Nullable Object key) { 85 return (Set<V>) super.removeAll(key); 86 } 87 88 /** 89 * {@inheritDoc} 90 * 91 * <p>Because a {@code SetMultimap} has unique values for a given key, this 92 * method returns a {@link Set}, instead of the {@link Collection} specified 93 * in the {@link Multimap} interface. 94 * 95 * <p>Any duplicates in {@code values} will be stored in the multimap once. 96 */ 97 @Override public Set<V> replaceValues( 98 @Nullable K key, Iterable<? extends V> values) { 99 return (Set<V>) super.replaceValues(key, values); 100 } 101 102 /** 103 * {@inheritDoc} 104 * 105 * <p>Though the method signature doesn't say so explicitly, the returned map 106 * has {@link Set} values. 107 */ 108 @Override public Map<K, Collection<V>> asMap() { 109 return super.asMap(); 110 } 111 112 /** 113 * Stores a key-value pair in the multimap. 114 * 115 * @param key key to store in the multimap 116 * @param value value to store in the multimap 117 * @return {@code true} if the method increased the size of the multimap, or 118 * {@code false} if the multimap already contained the key-value pair 119 */ 120 @Override public boolean put(@Nullable K key, @Nullable V value) { 121 return super.put(key, value); 122 } 123 124 /** 125 * Compares the specified object to this multimap for equality. 126 * 127 * <p>Two {@code SetMultimap} instances are equal if, for each key, they 128 * contain the same values. Equality does not depend on the ordering of keys 129 * or values. 130 */ 131 @Override public boolean equals(@Nullable Object object) { 132 return super.equals(object); 133 } 134 135 private static final long serialVersionUID = 7431625294878419160L; 136 } 137
