Package org.apache.commons.collections4.functors

Class MapTransformer<T,R>

java.lang.Object

org.apache.commons.collections4.functors.MapTransformer<T,R>

Type Parameters:

T - the type of the input to the function.

R - the type of the result of the function.

All Implemented Interfaces:

Serializable, Function<T,R>, Transformer<T,R>

public final class MapTransformer<T,R>
extends Object
implements Transformer<T,R>, Serializable

Transformer implementation that returns the value held in a specified map using the input parameter as a key.

Since:

3.0

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private final Map<? super T,? extends R>	iMap	The map of data to lookup in
private static final long	serialVersionUID	Serial version UID

Constructor Summary

Constructors

Modifier	Constructor	Description
private	MapTransformer(Map<? super T,? extends R> map)	Constructor that performs no validation.

Method Summary

Modifier and Type	Method	Description
Map<? super T,? extends R>	getMap()	Gets the map to lookup in.
static <I, O> Transformer<I,O>	mapTransformer(Map<? super I,? extends O> map)	Creates the transformer.
R	transform(T input)	Transforms the input to result by looking it up in a Map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.function.Function

andThen, compose

Methods inherited from interface org.apache.commons.collections4.Transformer

apply

Field Details

serialVersionUID

private static final long serialVersionUID

Serial version UID

See Also:

• Constant Field Values

iMap

private final Map<? super T,? extends R> iMap

The map of data to lookup in

Constructor Details

MapTransformer

private MapTransformer(Map<? super T,? extends R> map)

Constructor that performs no validation. Use mapTransformer if you want that.

Parameters:

map - the map to use for lookup, not cloned

Method Details

mapTransformer

public static <I,
O> Transformer<I,O> mapTransformer(Map<? super I,? extends O> map)

Creates the transformer.

If the map is null, a transformer that always returns null is returned.

Type Parameters:

I - the input type

O - the output type

Parameters:

map - the map, not cloned

Returns:

the transformer

getMap

public Map<? super T,? extends R> getMap()

Gets the map to lookup in.

Returns:

the map

Since:

3.1

transform

public R transform(T input)

Transforms the input to result by looking it up in a Map.

Specified by:

transform in interface Transformer<T,R>

Parameters:

input - the input object to transform

Returns:

the transformed result