| /* |
| * 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.GwtIncompatible; |
| import com.google.common.annotations.VisibleForTesting; |
| import java.io.IOException; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * 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. |
| * |
| * <p>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. |
| * |
| * <p>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. |
| * |
| * <p>Keys and values may be null. All optional multimap methods are supported, and all returned |
| * views are modifiable. |
| * |
| * <p>The lists returned by {@link #get}, {@link #removeAll}, and {@link #replaceValues} all |
| * implement {@link java.util.RandomAccess}. |
| * |
| * <p>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}. |
| * |
| * <p>See the Guava User Guide article on <a href= |
| * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multimap"> {@code |
| * Multimap}</a>. |
| * |
| * @author Jared Levy |
| * @since 2.0 |
| */ |
| @GwtCompatible(serializable = true, emulated = true) |
| public final class ArrayListMultimap<K, V> |
| extends ArrayListMultimapGwtSerializationDependencies<K, V> { |
| // Default from ArrayList |
| private static final int DEFAULT_VALUES_PER_KEY = 3; |
| |
| @VisibleForTesting transient int expectedValuesPerKey; |
| |
| /** |
| * Creates a new, empty {@code ArrayListMultimap} with the default initial capacities. |
| * |
| * <p>This method will soon be deprecated in favor of {@code |
| * MultimapBuilder.hashKeys().arrayListValues().build()}. |
| */ |
| public static <K, V> ArrayListMultimap<K, V> create() { |
| return new ArrayListMultimap<>(); |
| } |
| |
| /** |
| * Constructs an empty {@code ArrayListMultimap} with enough capacity to hold the specified |
| * numbers of keys and values without resizing. |
| * |
| * <p>This method will soon be deprecated in favor of {@code |
| * MultimapBuilder.hashKeys(expectedKeys).arrayListValues(expectedValuesPerKey).build()}. |
| * |
| * @param expectedKeys the expected number of distinct keys |
| * @param expectedValuesPerKey the expected average number of values per key |
| * @throws IllegalArgumentException if {@code expectedKeys} or {@code expectedValuesPerKey} is |
| * negative |
| */ |
| public static <K, V> ArrayListMultimap<K, V> create(int expectedKeys, int expectedValuesPerKey) { |
| return new ArrayListMultimap<>(expectedKeys, expectedValuesPerKey); |
| } |
| |
| /** |
| * Constructs an {@code ArrayListMultimap} with the same mappings as the specified multimap. |
| * |
| * <p>This method will soon be deprecated in favor of {@code |
| * MultimapBuilder.hashKeys().arrayListValues().build(multimap)}. |
| * |
| * @param multimap the multimap whose contents are copied to this multimap |
| */ |
| public static <K, V> ArrayListMultimap<K, V> create(Multimap<? extends K, ? extends V> multimap) { |
| return new ArrayListMultimap<>(multimap); |
| } |
| |
| private ArrayListMultimap() { |
| this(12, DEFAULT_VALUES_PER_KEY); |
| } |
| |
| private ArrayListMultimap(int expectedKeys, int expectedValuesPerKey) { |
| super(Platform.<K, Collection<V>>newHashMapWithExpectedSize(expectedKeys)); |
| checkNonnegative(expectedValuesPerKey, "expectedValuesPerKey"); |
| this.expectedValuesPerKey = expectedValuesPerKey; |
| } |
| |
| private ArrayListMultimap(Multimap<? extends K, ? extends V> multimap) { |
| this( |
| multimap.keySet().size(), |
| (multimap instanceof ArrayListMultimap) |
| ? ((ArrayListMultimap<?, ?>) multimap).expectedValuesPerKey |
| : DEFAULT_VALUES_PER_KEY); |
| putAll(multimap); |
| } |
| |
| /** |
| * Creates a new, empty {@code ArrayList} to hold the collection of values for an arbitrary key. |
| */ |
| @Override |
| List<V> createCollection() { |
| return new ArrayList<V>(expectedValuesPerKey); |
| } |
| |
| /** |
| * Reduces the memory used by this {@code ArrayListMultimap}, if feasible. |
| * |
| * @deprecated For a {@link ListMultimap} that automatically trims to size, use {@link |
| * ImmutableListMultimap}. If you need a mutable collection, remove the {@code trimToSize} |
| * call, or switch to a {@code HashMap<K, ArrayList<V>>}. |
| */ |
| @Deprecated |
| public void trimToSize() { |
| for (Collection<V> collection : backingMap().values()) { |
| ArrayList<V> arrayList = (ArrayList<V>) collection; |
| arrayList.trimToSize(); |
| } |
| } |
| |
| /** |
| * @serialData expectedValuesPerKey, number of distinct keys, and then for each distinct key: the |
| * key, number of values for that key, and the key's values |
| */ |
| @GwtIncompatible // java.io.ObjectOutputStream |
| private void writeObject(ObjectOutputStream stream) throws IOException { |
| stream.defaultWriteObject(); |
| Serialization.writeMultimap(this, stream); |
| } |
| |
| @GwtIncompatible // java.io.ObjectOutputStream |
| private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException { |
| stream.defaultReadObject(); |
| expectedValuesPerKey = DEFAULT_VALUES_PER_KEY; |
| int distinctKeys = Serialization.readCount(stream); |
| Map<K, Collection<V>> map = Maps.newHashMap(); |
| setMap(map); |
| Serialization.populateMultimap(this, stream, distinctKeys); |
| } |
| |
| @GwtIncompatible // Not needed in emulated source. |
| private static final long serialVersionUID = 0; |
| } |