org.jvnet.hk2.component

Class MultiMap<K,V>

java.lang.Object

org.jvnet.hk2.component.MultiMap<K,V>

Type Parameters:

K - The key of the multi-map

V - The types in the multi-map

All Implemented Interfaces:

Serializable, Cloneable

public class MultiMap<K,V>
extends Object
implements Serializable, Cloneable

Map from a key to multiple values. Order is significant among values, and null values are allowed, although null keys are not.

Author:

Kohsuke Kawaguchi, Jerome Dochez

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MultiMap() Creates an empty multi-map with default concurrency controls
MultiMap(MultiMap<K,V> base) Copy constructor.

Method Summary

Modifier and Type	Method and Description
void	add(K k, V v) Adds one more key-value pair.
MultiMap<K,V>	clone() Creates a copy of the map that contains the exact same key and value set.
boolean	contains(K k1, V k2) Checks if the map contains the given key(s), also extending the search to including the sub collection.
boolean	containsKey(K k) Checks if the map contains the given key.
Set<Map.Entry<K,List<V>>>	entrySet() Lists up all entries.
boolean	equals(Object another)
List<V>	get(K k) Returns the elements indexed by the provided key
V	getOne(K k) Gets the first value if any, or null.
int	hashCode()
Set<K>	keySet() Returns the set of keys associated with this MultiMap
void	mergeAll(MultiMap<K,V> another) This method merges all of the keys and values from another MultiMap into this MultiMap.
List<V>	remove(K key) Removes an key value from the map
boolean	remove(K key, V entry) Removes an key value pair from the map.
void	set(K k, Collection<? extends V> v) Replaces all the existing values associated with the key by the given value.
void	set(K k, V v) Replaces all the existing values associated with the key by the given single value.
int	size() Returns the size of the map.
String	toCommaSeparatedString()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiMap

public MultiMap()

Creates an empty multi-map with default concurrency controls

MultiMap

public MultiMap(MultiMap<K,V> base)

Copy constructor.

Parameters:

base - map to copy

Method Detail

keySet

public Set<K> keySet()

Returns the set of keys associated with this MultiMap

Returns:

The set of keys currently available in this MultiMap. Will not return null, but may return a Set of lenght zero

add

public final void add(K k,
                      V v)

Adds one more key-value pair.

Parameters:

k - key to store the entry under

v - value to store in the k's values.

set

public void set(K k,
                Collection<? extends V> v)

Replaces all the existing values associated with the key by the given value. If v is empty the key k will be removed from the MultiMap.

Parameters:

k - key for the values

v - Can be null or empty.

set

public void set(K k,
                V v)

Replaces all the existing values associated with the key by the given single value.

Parameters:

k - key for the values

v - singleton value for k key

This is short for set(k,Collections.singleton(v))

get

public final List<V> get(K k)

Returns the elements indexed by the provided key

Parameters:

k - key for the values

Returns:

Can be empty but never null. Read-only.

mergeAll

public void mergeAll(MultiMap<K,V> another)

This method merges all of the keys and values from another MultiMap into this MultiMap. If a key/value pair is found in both MultiMaps it is not re-added to this MultiMap, but is instead discarded

Parameters:

another - The MultiMap from which to add values to this MultiMap. If null this method does nothing

containsKey

public boolean containsKey(K k)

Checks if the map contains the given key.

Parameters:

k - key to test

Returns:

true if the map contains at least one element for this key

contains

public boolean contains(K k1,
                        V k2)

Checks if the map contains the given key(s), also extending the search to including the sub collection.

Parameters:

k1 - key from top collection

k2 - key (value) from inner collection

Returns:

true if the map contains at least one element for these keys

remove

public List<V> remove(K key)

Removes an key value from the map

Parameters:

key - key to be removed

Returns:

the value stored under this key or null if there was none

remove

public boolean remove(K key,
                      V entry)

Removes an key value pair from the map. If the list of entries for that key is empty after the remove it will be removed from the set of keys

Parameters:

key - key to be removed

entry - the entry to be removed from the key'ed list

Returns:

true if there was none that was deleted

getOne

public V getOne(K k)

Gets the first value if any, or null.

This is useful when you know the given key only has one value and you'd like to get to that value.

Parameters:

k - key for the values

Returns:

null if the key has no values or it has a value but the value is null.

entrySet

public Set<Map.Entry<K,List<V>>> entrySet()

Lists up all entries.

Returns:

a Set of Map.Entry of entries

toCommaSeparatedString

public String toCommaSeparatedString()

Returns:

the map as "key=value1,key=value2,...."

clone

public MultiMap<K,V> clone()
                    throws CloneNotSupportedException

Creates a copy of the map that contains the exact same key and value set. Keys and values won't cloned.

Overrides:

clone in class Object

Throws:

CloneNotSupportedException

size

public int size()

Returns the size of the map. This returns the numbers of keys in the map, not the number of values

Returns:

integer or 0 if the map is empty

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object another)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object