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/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Collection;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* A {@code Multimap} that cannot hold duplicate key-value pairs. Adding a key-value pair that's
* already in the multimap has no effect. See the {@link Multimap} documentation for information
* common to all multimaps.
*
* The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
* Set} of values, while {@link #entries} returns a {@code Set} of map entries. Though the method
* signature doesn't say so explicitly, the map returned by {@link #asMap} has {@code Set} values.
*
*
If the values corresponding to a single key should be ordered according to a {@link
* java.util.Comparator} (or the natural order), see the {@link SortedSetMultimap} subinterface.
*
*
Since the value collections are sets, the behavior of a {@code SetMultimap} is not specified
* if key or value objects already present in the multimap change in a manner that affects
* {@code equals} comparisons. Use caution if mutable objects are used as keys or values in a {@code
* SetMultimap}.
*
*
Warning: Do not modify either a key or a value of a {@code SetMultimap} in a way
* that affects its {@link Object#equals} behavior. Undefined behavior and bugs will result.
*
*
See the Guava User Guide article on {@code Multimap}.
*
* @author Jared Levy
* @since 2.0
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface SetMultimap
extends Multimap {
/**
* {@inheritDoc}
*
* Because a {@code SetMultimap} has unique values for a given key, this method returns a
* {@link Set}, instead of the {@link java.util.Collection} specified in the {@link Multimap}
* interface.
*/
@Override
Set get(@ParametricNullness K key);
/**
* {@inheritDoc}
*
* Because a {@code SetMultimap} has unique values for a given key, this method returns a
* {@link Set}, instead of the {@link java.util.Collection} specified in the {@link Multimap}
* interface.
*/
@CanIgnoreReturnValue
@Override
Set removeAll(@CheckForNull Object key);
/**
* {@inheritDoc}
*
* Because a {@code SetMultimap} has unique values for a given key, this method returns a
* {@link Set}, instead of the {@link java.util.Collection} specified in the {@link Multimap}
* interface.
*
*
Any duplicates in {@code values} will be stored in the multimap once.
*/
@CanIgnoreReturnValue
@Override
Set replaceValues(@ParametricNullness K key, Iterable values);
/**
* {@inheritDoc}
*
* Because a {@code SetMultimap} has unique values for a given key, this method returns a
* {@link Set}, instead of the {@link java.util.Collection} specified in the {@link Multimap}
* interface.
*/
@Override
Set> entries();
/**
* {@inheritDoc}
*
* Note: The returned map's values are guaranteed to be of type {@link Set}. To obtain
* this map with the more specific generic type {@code Map>}, call {@link
* Multimaps#asMap(SetMultimap)} instead.
*/
@Override
Map> asMap();
/**
* Compares the specified object to this multimap for equality.
*
* Two {@code SetMultimap} instances are equal if, for each key, they contain the same values.
* Equality does not depend on the ordering of keys or values.
*
*
An empty {@code SetMultimap} is equal to any other empty {@code Multimap}, including an
* empty {@code ListMultimap}.
*/
@Override
boolean equals(@CheckForNull Object obj);
}