    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
    017    package com.google.common.collect;
    018
    019    import com.google.common.annotations.GwtCompatible;
    020
    021    import java.util.Collection;
    022    import java.util.Map;
    023    import java.util.Set;
    024
    025    import 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 2.0 (imported from Google Collections Library)
    038     */
    039    @GwtCompatible
    040    public 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    }