/* * 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 static com.google.common.collect.CollectPreconditions.checkNonnegative; import com.google.common.annotations.GwtCompatible; import com.google.common.annotations.VisibleForTesting; import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.List; /** * Implementation of {@code Multimap} that uses an {@code ArrayList} to store * the values for a given key. A {@link HashMap} associates each key with an * {@link ArrayList} of values. * *
When iterating through the collections supplied by this class, the * ordering of values for a given key agrees with the order in which the values * were added. * *
This multimap allows duplicate key-value pairs. After adding a new * key-value pair equal to an existing key-value pair, the {@code * ArrayListMultimap} will contain entries for both the new value and the old * value. * *
Keys and values may be null. All optional multimap methods are supported, * and all returned views are modifiable. * *
The lists returned by {@link #get}, {@link #removeAll}, and {@link * #replaceValues} all implement {@link java.util.RandomAccess}. * *
This class is not threadsafe when any concurrent operations update the * multimap. Concurrent read operations will work correctly. To allow concurrent * update operations, wrap your multimap with a call to {@link * Multimaps#synchronizedListMultimap}. * *
See the Guava User Guide article on
* {@code Multimap}.
*
* @author Jared Levy
* @since 2.0 (imported from Google Collections Library)
*/
@GwtCompatible(serializable = true, emulated = true)
public final class ArrayListMultimap