javadoc.com.google.common.collect.ArrayListMultimap.html Maven / Gradle / Ivy
ArrayListMultimap (Guava: Google Core Libraries for Java 11.0.1 API)
Overview
Package
Class
Use
Tree
Deprecated
Index
Help
PREV CLASS
NEXT CLASS
FRAMES
NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD
DETAIL: FIELD | CONSTR | METHOD
com.google.common.collect
Class ArrayListMultimap<K,V>
java.lang.Object
com.google.common.collect.ArrayListMultimap<K,V>
- All Implemented Interfaces:
- ListMultimap<K,V>, Multimap<K,V>, Serializable
@GwtCompatible(serializable=true,
emulated=true)
public final class ArrayListMultimap<K,V>
- extends Object
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 get(K)
, removeAll(java.lang.Object)
, and 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
.
- Since:
- 2.0 (imported from Google Collections Library)
- Author:
- Jared Levy
- See Also:
- Serialized Form
Method Summary | ||
---|---|---|
Map<K,Collection<V>> |
asMap()
Returns a map view that associates each key with the corresponding values in the multimap. |
|
void |
clear()
Removes all key-value pairs from the multimap. |
|
boolean |
containsEntry(Object key,
Object value)
Returns true if the multimap contains the specified key-value pair. |
|
boolean |
containsKey(Object key)
Returns true if the multimap contains any values for the specified
key. |
|
boolean |
containsValue(Object value)
Returns true if the multimap contains the specified value for any
key. |
|
static
|
create()
Creates a new, empty ArrayListMultimap with the default initial
capacities. |
|
static
|
create(int expectedKeys,
int expectedValuesPerKey)
Constructs an empty ArrayListMultimap with enough capacity to hold
the specified numbers of keys and values without resizing. |
|
static
|
create(Multimap<? extends K,? extends V> multimap)
Constructs an ArrayListMultimap with the same mappings as the
specified multimap. |
|
Collection<Map.Entry<K,V>> |
entries()
Returns a collection of all key-value pairs. |
|
boolean |
equals(Object object)
Compares the specified object to this multimap for equality. |
|
List<V> |
get(K key)
Returns a collection view of all values associated with a key. |
|
int |
hashCode()
Returns the hash code for this multimap. |
|
boolean |
isEmpty()
Returns true if the multimap contains no key-value pairs. |
|
Multiset<K> |
keys()
Returns a collection, which may contain duplicates, of all keys. |
|
Set<K> |
keySet()
Returns the set of all keys, each appearing once in the returned set. |
|
boolean |
put(K key,
V value)
Stores a key-value pair in the multimap. |
|
boolean |
putAll(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key. |
|
boolean |
putAll(Multimap<? extends K,? extends V> multimap)
Copies all of another multimap's key-value pairs into this multimap. |
|
boolean |
remove(Object key,
Object value)
Removes a key-value pair from the multimap. |
|
List<V> |
removeAll(Object key)
Removes all values associated with a given key. |
|
List<V> |
replaceValues(K key,
Iterable<? extends V> values)
Stores a collection of values with the same key, replacing any existing values for that key. |
|
int |
size()
Returns the number of key-value pairs in the multimap. |
|
String |
toString()
Returns a string representation of the multimap, generated by calling toString on the map returned by Multimap.asMap() . |
|
void |
trimToSize()
Reduces the memory used by this ArrayListMultimap , if feasible. |
|
Collection<V> |
values()
Returns a collection of all values in the multimap. |
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, hashCode, isEmpty, keys, keySet, putAll, putAll, remove, size, values |
Method Detail |
---|
create
public static <K,V> ArrayListMultimap<K,V> create()
- Creates a new, empty
ArrayListMultimap
with the default initial capacities.
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.- Parameters:
expectedKeys
- the expected number of distinct keysexpectedValuesPerKey
- the expected average number of values per key- Throws:
IllegalArgumentException
- ifexpectedKeys
orexpectedValuesPerKey
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.- Parameters:
multimap
- the multimap whose contents are copied to this multimap
trimToSize
public void trimToSize()
- Reduces the memory used by this
ArrayListMultimap
, if feasible.
get
public List<V> get(@Nullable K key)
- Returns a collection view of all values associated with a key. If no
mappings in the multimap have the provided key, an empty collection is
returned.
Changes to the returned collection will update the underlying multimap, and vice versa.
The returned collection is not serializable.
Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.- Specified by:
get
in interfaceListMultimap<K,V>
- Specified by:
get
in interfaceMultimap<K,V>
- Parameters:
key
- key to search for in multimap- Returns:
- the collection of values that the key maps to
removeAll
public List<V> removeAll(@Nullable Object key)
- Removes all values associated with a given key.
The returned collection is immutable.
Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.- Specified by:
removeAll
in interfaceListMultimap<K,V>
- Specified by:
removeAll
in interfaceMultimap<K,V>
- Parameters:
key
- key of entries to remove from the multimap- Returns:
- the collection of removed values, or an empty collection if no values were associated with the provided key. The collection may be modifiable, but updating it will have no effect on the multimap.
replaceValues
public List<V> replaceValues(@Nullable K key, Iterable<? extends V> values)
- Stores a collection of values with the same key, replacing any existing
values for that key.
The returned collection is immutable.
Because the values for a given key may have duplicates and follow the insertion ordering, this method returns a
List
, instead of theCollection
specified in theMultimap
interface.- Specified by:
replaceValues
in interfaceListMultimap<K,V>
- Specified by:
replaceValues
in interfaceMultimap<K,V>
- Parameters:
key
- key to store in the multimapvalues
- values to store in the multimap- Returns:
- the collection of replaced values, or an empty collection if no values were previously associated with the key. The collection may be modifiable, but updating it will have no effect on the multimap.
put
public boolean put(@Nullable K key, @Nullable V value)
- Stores a key-value pair in the multimap.
- Parameters:
key
- key to store in the multimapvalue
- value to store in the multimap- Returns:
true
always
asMap
public Map<K,Collection<V>> asMap()
- Returns a map view that associates each key with the corresponding values
in the multimap. Changes to the returned map, such as element removal, will
update the underlying multimap. The map does not support
setValue()
on its entries,put
, orputAll
.When passed a key that is present in the map,
asMap().get(Object)
has the same behavior asMultimap.get(K)
, returning a live collection. When passed a key that is not present, however,asMap().get(Object)
returnsnull
instead of an empty collection.Though the method signature doesn't say so explicitly, the returned map has
List
values.- Specified by:
asMap
in interfaceListMultimap<K,V>
- Specified by:
asMap
in interfaceMultimap<K,V>
- Returns:
- a map view from a key to its collection of values
equals
public boolean equals(@Nullable Object object)
- Compares the specified object to this multimap for equality.
Two
ListMultimap
instances are equal if, for each key, they contain the same values in the same order. If the value orderings disagree, the multimaps will not be considered equal.- Specified by:
equals
in interfaceListMultimap<K,V>
- Specified by:
equals
in interfaceMultimap<K,V>
size
public int size()
- Description copied from interface:
Multimap
- Returns the number of key-value pairs in the multimap.
isEmpty
public boolean isEmpty()
- Description copied from interface:
Multimap
- Returns
true
if the multimap contains no key-value pairs.
containsKey
public boolean containsKey(@Nullable Object key)
- Description copied from interface:
Multimap
- Returns
true
if the multimap contains any values for the specified key.- Specified by:
containsKey
in interfaceMultimap<K,V>
- Parameters:
key
- key to search for in multimap
containsValue
public boolean containsValue(@Nullable Object value)
- Description copied from interface:
Multimap
- Returns
true
if the multimap contains the specified value for any key.- Specified by:
containsValue
in interfaceMultimap<K,V>
- Parameters:
value
- value to search for in multimap
containsEntry
public boolean containsEntry(@Nullable Object key, @Nullable Object value)
- Description copied from interface:
Multimap
- Returns
true
if the multimap contains the specified key-value pair.- Specified by:
containsEntry
in interfaceMultimap<K,V>
- Parameters:
key
- key to search for in multimapvalue
- value to search for in multimap
remove
public boolean remove(@Nullable Object key, @Nullable Object value)
- Description copied from interface:
Multimap
- Removes a key-value pair from the multimap.
- Parameters:
key
- key of entry to remove from the multimapvalue
- value of entry to remove the multimap- Returns:
true
if the multimap changed
putAll
public boolean putAll(@Nullable K key, Iterable<? extends V> values)
- Description copied from interface:
Multimap
- Stores a collection of values with the same key.
- Parameters:
key
- key to store in the multimapvalues
- values to store in the multimap- Returns:
true
if the multimap changed
putAll
public boolean putAll(Multimap<? extends K,? extends V> multimap)
- Description copied from interface:
Multimap
- Copies all of another multimap's key-value pairs into this multimap. The
order in which the mappings are added is determined by
multimap.entries()
.- Parameters:
multimap
- mappings to store in this multimap- Returns:
true
if the multimap changed
clear
public void clear()
- Description copied from interface:
Multimap
- Removes all key-value pairs from the multimap.
keySet
public Set<K> keySet()
- Description copied from interface:
Multimap
- Returns the set of all keys, each appearing once in the returned set.
Changes to the returned set will update the underlying multimap, and vice
versa.
- Returns:
- the collection of distinct keys
keys
public Multiset<K> keys()
- Description copied from interface:
Multimap
- Returns a collection, which may contain duplicates, of all keys. The number
of times of key appears in the returned multiset equals the number of
mappings the key has in the multimap. Changes to the returned multiset will
update the underlying multimap, and vice versa.
- Returns:
- a multiset with keys corresponding to the distinct keys of the multimap and frequencies corresponding to the number of values that each key maps to
values
public Collection<V> values()
- Returns a collection of all values in the multimap. Changes to the returned
collection will update the underlying multimap, and vice versa.
The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.
- Returns:
- collection of values, which may include the same value multiple times if it occurs in multiple mappings
entries
public Collection<Map.Entry<K,V>> entries()
- Returns a collection of all key-value pairs. Changes to the returned
collection will update the underlying multimap, and vice versa. The entries
collection does not support the
add
oraddAll
operations.The iterator generated by the returned collection traverses the values for one key, followed by the values of a second key, and so on.
Each entry is an immutable snapshot of a key-value mapping in the multimap, taken at the time the entry is returned by a method call to the collection or its iterator.
- Returns:
- collection of map entries consisting of key-value pairs
hashCode
public int hashCode()
- Returns the hash code for this multimap.
The hash code of a multimap is defined as the hash code of the map view, as returned by
Multimap.asMap()
.- See Also:
Map.hashCode()
toString
public String toString()
- Returns a string representation of the multimap, generated by calling
toString
on the map returned byMultimap.asMap()
.- Returns:
- a string representation of the multimap
|
||||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
Copyright © 2010-2012. All Rights Reserved.