de.fhg.fokus.xtensions.pair

Class PairExtensions

java.lang.Object

de.fhg.fokus.xtensions.pair.PairExtensions

public final class PairExtensions
extends Object

Provides static extension methods for the Pair class.

Method Summary

Modifier and Type	Method and Description
static <K,V,R> R	combine(Pair<K,V> pair, Functions.Function2<? super K,? super V,? extends R> combiner) Will call the combiner with the key and the value of pair and returns the result of the combiner call.
static <K,V> Pair<K,V>	operator_doubleArrow(Pair<K,V> pair, Procedures.Procedure2<? super K,? super V> consumer) Will call the given consumer with the key and value extracted from pair.
static <K,V,R> Optional<R>	safeCombine(Pair<K,V> pair, Functions.Function2<? super K,? super V,? extends R> combiner) If pair, or key or value of the given pair is null, this function returns an empty Optional.

Methods inherited from class java.lang.Object

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

Method Detail

operator_doubleArrow

public static <K,V> Pair<K,V> operator_doubleArrow(Pair<K,V> pair,
                                                   Procedures.Procedure2<? super K,? super V> consumer)

Will call the given consumer with the key and value extracted from pair. If the given consumer throws an exception it will be thrown out of this method.

Type Parameters:

K - Type of key element of pair

V - Type of value element of pair

Parameters:

pair - the Pair from which key and value are taken and passed to consumer.

consumer - will be called with key and value from pair

Returns:

the same reference passed in as pair

combine

public static <K,V,R> R combine(Pair<K,V> pair,
                                Functions.Function2<? super K,? super V,? extends R> combiner)

Will call the combiner with the key and the value of pair and returns the result of the combiner call. This function can be used as a flatMap function by returning a new Pair.

Type Parameters:

K - Type of key element of pair

V - Type of value element of pair

R - Type of the result of the combination of key and value

Parameters:

pair - the Pair from which key and value are taken and passed to combiner

combiner - the function to be called with key and value from pair

Returns:

result returned by combiner.

safeCombine

public static <K,V,R> Optional<R> safeCombine(Pair<K,V> pair,
                                              Functions.Function2<? super K,? super V,? extends R> combiner)

If pair, or key or value of the given pair is null, this function returns an empty Optional. Otherwise the combiner will be called with the key and the value of pair and returns the result of the combiner call wrapped in an Optional. If the result of combiner is null an empty Optional will be returned.

Type Parameters:

K - Type of key element of pair

V - Type of value element of pair

R - Type of the result of the combination of key and value

Parameters:

pair - the Pair from which key and value are taken and passed to combiner if none of them is null.

combiner - the function to be called with non-null key and value from pair

Returns:

result returned by combiner wrapped in an Optional