Package org.apache.commons.collections4.multimap

Class TransformedMultiValuedMap<K,V>

java.lang.Object

org.apache.commons.collections4.multimap.AbstractMultiValuedMapDecorator<K,V>

org.apache.commons.collections4.multimap.TransformedMultiValuedMap<K,V>

Type Parameters:

K - the type of the keys in this map

V - the type of the values in this map

All Implemented Interfaces:

Serializable, MultiValuedMap<K,V>

public class TransformedMultiValuedMap<K,V>
extends AbstractMultiValuedMapDecorator<K,V>

Decorates another MultiValuedMap to transform objects that are added.

This class affects the MultiValuedMap put methods. Thus objects must be removed or searched for using their transformed form. For example, if the transformation converts Strings to Integers, you must use the Integer form to remove objects.

Note that TransformedMultiValuedMap is not synchronized and is not thread-safe.

Since:

4.1

See Also:

• Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	TransformedMultiValuedMap(MultiValuedMap<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)	Constructor that wraps (not copies).

Method Summary

Modifier and Type	Method	Description
boolean	put(K key, V value)	Adds a key-value mapping to this multivalued map.
boolean	putAll(Map<? extends K,? extends V> map)	Copies all mappings from the specified map to this multivalued map (optional operation).
boolean	putAll(K key, Iterable<? extends V> values)	Adds a mapping to the specified key for all values contained in the given Iterable.
boolean	putAll(MultiValuedMap<? extends K,? extends V> map)	Copies all mappings from the specified map to this multivalued map (optional operation).
static <K, V> TransformedMultiValuedMap<K,V>	transformedMap(MultiValuedMap<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)	Factory method to create a transforming MultiValuedMap that will transform existing contents of the specified map.
static <K, V> TransformedMultiValuedMap<K,V>	transformingMap(MultiValuedMap<K,V> map, Transformer<? super K,? extends K> keyTransformer, Transformer<? super V,? extends V> valueTransformer)	Factory method to create a transforming MultiValuedMap.
protected K	transformKey(K object)	Transforms a key.
protected V	transformValue(V object)	Transforms a value.

Methods inherited from class org.apache.commons.collections4.multimap.AbstractMultiValuedMapDecorator

asMap, clear, containsKey, containsMapping, containsValue, decorated, entries, equals, get, hashCode, isEmpty, keys, keySet, mapIterator, remove, removeMapping, size, toString, values

Methods inherited from class java.lang.Object

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

Constructor Details

TransformedMultiValuedMap

protected TransformedMultiValuedMap(MultiValuedMap<K,V> map,
 Transformer<? super K,? extends K> keyTransformer,
 Transformer<? super V,? extends V> valueTransformer)

Constructor that wraps (not copies).

If there are any elements already in the collection being decorated, they are NOT transformed.

Parameters:

map - the MultiValuedMap to decorate, may not be null

keyTransformer - the transformer to use for key conversion, null means no conversion

valueTransformer - the transformer to use for value conversion, null means no conversion

Throws:

NullPointerException - if map is null

Method Details

transformedMap

public static <K,
V> TransformedMultiValuedMap<K,V> transformedMap(MultiValuedMap<K,V> map,
 Transformer<? super K,? extends K> keyTransformer,
 Transformer<? super V,? extends V> valueTransformer)

Factory method to create a transforming MultiValuedMap that will transform existing contents of the specified map.

If there are any elements already in the map being decorated, they will be transformed by this method. Contrast this with transformingMap(MultiValuedMap, Transformer, Transformer).

Type Parameters:

K - the key type

V - the value type

Parameters:

map - the MultiValuedMap to decorate, may not be null

keyTransformer - the transformer to use for key conversion, null means no conversion

valueTransformer - the transformer to use for value conversion, null means no conversion

Returns:

a new transformed MultiValuedMap

Throws:

NullPointerException - if map is null

transformingMap

public static <K,
V> TransformedMultiValuedMap<K,V> transformingMap(MultiValuedMap<K,V> map,
 Transformer<? super K,? extends K> keyTransformer,
 Transformer<? super V,? extends V> valueTransformer)

Factory method to create a transforming MultiValuedMap.

If there are any elements already in the map being decorated, they are NOT transformed. Contrast this with transformedMap(MultiValuedMap, Transformer, Transformer).

Type Parameters:

K - the key type

V - the value type

Parameters:

map - the MultiValuedMap to decorate, may not be null

keyTransformer - the transformer to use for key conversion, null means no conversion

valueTransformer - the transformer to use for value conversion, null means no conversion

Returns:

a new transformed MultiValuedMap

Throws:

NullPointerException - if map is null

put

public boolean put(K key,
 V value)

Description copied from interface: MultiValuedMap

Adds a key-value mapping to this multivalued map.

Unlike a normal Map the previous value is not replaced. Instead, the new value is added to the collection stored against the key. Depending on the collection type used, duplicate key-value mappings may be allowed.

The method will return true if the size of the multivalued map has been increased because of this operation.

Specified by:

put in interface MultiValuedMap<K,V>

Overrides:

put in class AbstractMultiValuedMapDecorator<K,V>

Parameters:

key - the key to store against

value - the value to add to the collection at the key

Returns:

true if the map changed as a result of this put operation, or false if the map already contained the key-value mapping and the collection type does not allow duplicate values, e.g. when using a Set

putAll

public boolean putAll(K key,
 Iterable<? extends V> values)

Description copied from interface: MultiValuedMap

Adds a mapping to the specified key for all values contained in the given Iterable.

Specified by:

putAll in interface MultiValuedMap<K,V>

Overrides:

putAll in class AbstractMultiValuedMapDecorator<K,V>

Parameters:

key - the key to store against

values - the values to add to the collection at the key, may not be null

Returns:

true if the map changed as a result of this operation

putAll

public boolean putAll(Map<? extends K,? extends V> map)

Description copied from interface: MultiValuedMap

Copies all mappings from the specified map to this multivalued map (optional operation).

The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map.

The behavior of this operation is undefined if the specified map is modified while the operation is in progress.

Specified by:

putAll in interface MultiValuedMap<K,V>

Overrides:

putAll in class AbstractMultiValuedMapDecorator<K,V>

Parameters:

map - mappings to be stored in this map, may not be null

Returns:

true if the map changed as a result of this operation

putAll

public boolean putAll(MultiValuedMap<? extends K,? extends V> map)

Description copied from interface: MultiValuedMap

Copies all mappings from the specified map to this multivalued map (optional operation).

The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map.

The behavior of this operation is undefined if the specified map is modified while the operation is in progress.

Specified by:

putAll in interface MultiValuedMap<K,V>

Overrides:

putAll in class AbstractMultiValuedMapDecorator<K,V>

Parameters:

map - mappings to be stored in this map, may not be null

Returns:

true if the map changed as a result of this operation

transformKey

protected K transformKey(K object)

Transforms a key.

The transformer itself may throw an exception if necessary.

Parameters:

object - the object to transform

Returns:

the transformed object

transformValue

protected V transformValue(V object)

Transforms a value.

The transformer itself may throw an exception if necessary.

Parameters:

object - the object to transform

Returns:

the transformed object