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.Map;
023import java.util.Set;
024
025import javax.annotation.Nullable;
026
027/**
028 * A {@code Multimap} that cannot hold duplicate key-value pairs. Adding a
029 * key-value pair that's already in the multimap has no effect.
030 *
031 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods
032 * each return a {@link Set} of values, while {@link #entries} returns a {@code
033 * Set} of map entries. Though the method signature doesn't say so explicitly,
034 * the map returned by {@link #asMap} has {@code Set} values.
035 *
036 * @author Jared Levy
037 * @since 2 (imported from Google Collections Library)
038 */
039@GwtCompatible
040public interface SetMultimap<K, V> extends Multimap<K, V> {
041  /**
042   * {@inheritDoc}
043   *
044   * <p>Because a {@code SetMultimap} has unique values for a given key, this
045   * method returns a {@link Set}, instead of the {@link java.util.Collection}
046   * specified in the {@link Multimap} interface.
047   */
048  @Override
049  Set<V> get(@Nullable K key);
050
051  /**
052   * {@inheritDoc}
053   *
054   * <p>Because a {@code SetMultimap} has unique values for a given key, this
055   * method returns a {@link Set}, instead of the {@link java.util.Collection}
056   * specified in the {@link Multimap} interface.
057   */
058  @Override
059  Set<V> removeAll(@Nullable Object key);
060
061  /**
062   * {@inheritDoc}
063   *
064   * <p>Because a {@code SetMultimap} has unique values for a given key, this
065   * method returns a {@link Set}, instead of the {@link java.util.Collection}
066   * specified in the {@link Multimap} interface.
067   *
068   * <p>Any duplicates in {@code values} will be stored in the multimap once.
069   */
070  @Override
071  Set<V> replaceValues(K key, Iterable<? extends V> values);
072
073  /**
074   * {@inheritDoc}
075   *
076   * <p>Because a {@code SetMultimap} has unique values for a given key, this
077   * method returns a {@link Set}, instead of the {@link java.util.Collection}
078   * specified in the {@link Multimap} interface.
079   */
080  @Override
081  Set<Map.Entry<K, V>> entries();
082
083  /**
084   * {@inheritDoc}
085   *
086   * <p>Though the method signature doesn't say so explicitly, the returned map
087   * has {@link Set} values.
088   */
089  @Override
090  Map<K, Collection<V>> asMap();
091
092  /**
093   * Compares the specified object to this multimap for equality.
094   *
095   * <p>Two {@code SetMultimap} instances are equal if, for each key, they
096   * contain the same values. Equality does not depend on the ordering of keys
097   * or values.
098   */
099  @Override
100  boolean equals(@Nullable Object obj);
101}