Package com.google.common.collect

Class ArrayListMultimap<K,V>

java.lang.Object

com.google.common.collect.AbstractMultimap<K,V>

com.google.common.collect.AbstractMapBasedMultimap<K,V>

com.google.common.collect.AbstractListMultimap<K,V>

com.google.common.collect.ArrayListMultimapGwtSerializationDependencies<K,V>

com.google.common.collect.ArrayListMultimap<K,V>

All Implemented Interfaces:

ListMultimap<K,V>, Multimap<K,V>, java.io.Serializable

@GwtCompatible(serializable=true,
               emulated=true)
public final class ArrayListMultimap<K,V>
extends ArrayListMultimapGwtSerializationDependencies<K,V>

Implementation of Multimap that uses an ArrayList to store the values for a given key. A HashMap associates each key with an 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 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 AbstractListMultimap.get(K), AbstractListMultimap.removeAll(java.lang.Object), and AbstractListMultimap.replaceValues(K, java.lang.Iterable<? extends V>) all implement 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 Multimaps.synchronizedListMultimap(com.google.common.collect.ListMultimap<K, V>).

See the Guava User Guide article on Multimap.

Since:

2.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.google.common.collect.AbstractMapBasedMultimap

AbstractMapBasedMultimap.NavigableAsMap, AbstractMapBasedMultimap.NavigableKeySet, AbstractMapBasedMultimap.WrappedCollection, AbstractMapBasedMultimap.WrappedList, AbstractMapBasedMultimap.WrappedNavigableSet, AbstractMapBasedMultimap.WrappedSet, AbstractMapBasedMultimap.WrappedSortedSet

Nested classes/interfaces inherited from class com.google.common.collect.AbstractMultimap

AbstractMultimap.Entries, AbstractMultimap.EntrySet, AbstractMultimap.Values

Field Summary

Fields

Modifier and Type	Field	Description
private static int	DEFAULT_VALUES_PER_KEY
(package private) int	expectedValuesPerKey
private static long	serialVersionUID

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ArrayListMultimap()
private	ArrayListMultimap(int expectedKeys, int expectedValuesPerKey)
private	ArrayListMultimap(Multimap<? extends K,? extends V> multimap)

Method Summary

Modifier and Type	Method	Description
static <K,V> ArrayListMultimap<K,V>	create()	Creates a new, empty ArrayListMultimap with the default initial capacities.
static <K,V> ArrayListMultimap<K,V>	create(int expectedKeys, int expectedValuesPerKey)	Constructs an empty ArrayListMultimap with enough capacity to hold the specified numbers of keys and values without resizing.
static <K,V> ArrayListMultimap<K,V>	create(Multimap<? extends K,? extends V> multimap)	Constructs an ArrayListMultimap with the same mappings as the specified multimap.
(package private) java.util.List<V>	createCollection()	Creates a new, empty ArrayList to hold the collection of values for an arbitrary key.
private void	readObject(java.io.ObjectInputStream stream)
void	trimToSize()	Deprecated. For a ListMultimap that automatically trims to size, use ImmutableListMultimap.
private void	writeObject(java.io.ObjectOutputStream stream)

Methods inherited from class com.google.common.collect.AbstractListMultimap

asMap, createUnmodifiableEmptyCollection, equals, get, put, removeAll, replaceValues, unmodifiableCollectionSubclass, wrapCollection

Methods inherited from class com.google.common.collect.AbstractMapBasedMultimap

backingMap, clear, containsKey, createAsMap, createCollection, createEntries, createKeys, createKeySet, createMaybeNavigableAsMap, createMaybeNavigableKeySet, createValues, entries, entryIterator, entrySpliterator, forEach, setMap, size, valueIterator, values, valueSpliterator, wrapList

Methods inherited from class com.google.common.collect.AbstractMultimap

containsEntry, containsValue, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.google.common.collect.Multimap

clear, containsEntry, containsKey, containsValue, entries, forEach, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, size, values

Field Detail

DEFAULT_VALUES_PER_KEY

private static final int DEFAULT_VALUES_PER_KEY

See Also:

Constant Field Values

expectedValuesPerKey

transient int expectedValuesPerKey

serialVersionUID

@GwtIncompatible
private static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

ArrayListMultimap

private ArrayListMultimap()

ArrayListMultimap

private ArrayListMultimap(int expectedKeys,
                          int expectedValuesPerKey)

ArrayListMultimap

private ArrayListMultimap(Multimap<? extends K,? extends V> multimap)

Method Detail

create

public static <K,V> ArrayListMultimap<K,V> create()

Creates a new, empty ArrayListMultimap with the default initial capacities.

This method will soon be deprecated in favor of MultimapBuilder.hashKeys().arrayListValues().build().

create

public static <K,V> ArrayListMultimap<K,V> create(int expectedKeys,
                                                              int expectedValuesPerKey)

Constructs an empty ArrayListMultimap with enough capacity to hold the specified numbers of keys and values without resizing.

This method will soon be deprecated in favor of MultimapBuilder.hashKeys(expectedKeys).arrayListValues(expectedValuesPerKey).build().

Parameters:

expectedKeys - the expected number of distinct keys

expectedValuesPerKey - the expected average number of values per key

Throws:

java.lang.IllegalArgumentException - if expectedKeys or expectedValuesPerKey is negative

create

public static <K,V> ArrayListMultimap<K,V> create(Multimap<? extends K,? extends V> multimap)

Constructs an ArrayListMultimap with the same mappings as the specified multimap.

This method will soon be deprecated in favor of MultimapBuilder.hashKeys().arrayListValues().build(multimap).

Parameters:

multimap - the multimap whose contents are copied to this multimap

createCollection

java.util.List<V> createCollection()

Creates a new, empty ArrayList to hold the collection of values for an arbitrary key.

Specified by:

createCollection in class AbstractListMultimap<K,V>

Returns:

an empty collection of values

trimToSize

@Deprecated
public void trimToSize()

Deprecated.

For a ListMultimap that automatically trims to size, use ImmutableListMultimap. If you need a mutable collection, remove the trimToSize call, or switch to a HashMap<K, ArrayList<V>>.

Reduces the memory used by this ArrayListMultimap, if feasible.

writeObject

@GwtIncompatible
private void writeObject(java.io.ObjectOutputStream stream)
                  throws java.io.IOException

Throws:

java.io.IOException

readObject

@GwtIncompatible
private void readObject(java.io.ObjectInputStream stream)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException

Throws:

java.io.IOException

java.lang.ClassNotFoundException