Package io.atlassian.fugue

Class Pair<A,B>

java.lang.Object

io.atlassian.fugue.Pair<A,B>

All Implemented Interfaces:

java.io.Serializable

public final class Pair<A,B>
extends java.lang.Object
implements java.io.Serializable

Represents a pair of objects.

Since:

1.0

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static int	HALF_WORD
private A	left
private B	right
private static long	serialVersionUID

Constructor Summary

Constructors

Constructor	Description
Pair(A left, B right)	Constructor for Pair.

Method Summary

Modifier and Type	Method	Description
static <A,B> Pair<B,B>	ap(Pair<A,A> aa, Pair<java.util.function.Function<A,B>,java.util.function.Function<A,B>> ff)	Performs function application within an homogeneous pair (applicative functor pattern).
<AA,BB> Pair<AA,BB>	bimap(java.util.function.Function<? super A,? extends AA> fLeft, java.util.function.Function<? super B,? extends BB> fRight)	Applies functions to each of the left and right values to produce a new pair.
boolean	equals(java.lang.Object o)
<R> R	fold(java.util.function.BiFunction<? super A,? super B,R> f)	Applies a function to left and right values to produce a single result.
int	hashCode()
A	left()	Accessor method for the left value of the pair.
<AA> Pair<AA,B>	leftMap(java.util.function.Function<? super A,AA> fLeft)	Applies a function to the left value to produce a new Pair.
static <A> java.util.function.Function<Pair<A,?>,A>	leftValue()	Function for accessing the left value of pairs.
static <A,B> Pair<B,B>	map(Pair<A,A> aa, java.util.function.Function<A,B> f)	Apply a function to both elements of an homogeneous pair.
static <A,B> Pair<A,B>	pair(A left, B right)	Factory method for static Pair growth.
static <A,B> java.util.function.BiFunction<A,B,Pair<A,B>>	pairs()	Factory method for a Pair factory function.
B	right()	Accessor method for the right value of the pair.q
<BB> Pair<A,BB>	rightMap(java.util.function.Function<? super B,BB> fRight)	Applies a function to the right value to produce a new Pair.
static <B> java.util.function.Function<Pair<?,B>,B>	rightValue()	Function for accessing the right value of pairs.
Pair<B,A>	swap()
java.lang.String	toString()
static <A,B> java.lang.Iterable<Pair<A,B>>	zip(java.lang.Iterable<A> as, java.lang.Iterable<B> bs)	Zips two iterables into a single iterable that produces pairs.
static <A,B> java.util.Optional<Pair<A,B>>	zip(java.util.Optional<A> oA, java.util.Optional<B> oB)	Zips the two given optionals into an optional of a pair.

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

HALF_WORD

private static final int HALF_WORD

See Also:

Constant Field Values

left

private final A left

right

private final B right

Constructor Detail

Pair

public Pair(A left,
            B right)

Constructor for Pair.

Parameters:

left - value, cannot be null

right - value, cannot be null

Method Detail

pair

public static <A,B> Pair<A,B> pair(A left,
                                               B right)

Factory method for static Pair growth.

Type Parameters:

A - the left value type

B - the right value type

Parameters:

left - value, cannot be null

right - value, cannot be null

Returns:

the Pair containing the passed values

pairs

public static <A,B> java.util.function.BiFunction<A,B,Pair<A,B>> pairs()

Factory method for a Pair factory function.

Type Parameters:

A - the left value type

B - the right value type

Returns:

a function that constructs Pairs

leftValue

public static <A> java.util.function.Function<Pair<A,?>,A> leftValue()

Function for accessing the left value of pairs.

Type Parameters:

A - the left value type

Returns:

a Function that given a Pair returns the left side value

Since:

1.1

rightValue

public static <B> java.util.function.Function<Pair<?,B>,B> rightValue()

Function for accessing the right value of pairs.

Type Parameters:

B - the right value type

Returns:

a Function that given a Pair returns the right side value

Since:

1.1

ap

public static <A,B> Pair<B,B> ap(Pair<A,A> aa,
                                             Pair<java.util.function.Function<A,B>,java.util.function.Function<A,B>> ff)

Performs function application within an homogeneous pair (applicative functor pattern).

Parameters:

aa - an homogeneous pair

ff - The pair of functions to apply.

Returns:

A new pair after applying the given pair of functions through aa.

map

public static <A,B> Pair<B,B> map(Pair<A,A> aa,
                                              java.util.function.Function<A,B> f)

Apply a function to both elements of an homogeneous pair.

Parameters:

aa - an homogeneous pair

f - function to apply to both elements of aa

Returns:

A new pair after applying the function to aa elements.

zip

public static <A,B> java.lang.Iterable<Pair<A,B>> zip(java.lang.Iterable<A> as,
                                                                  java.lang.Iterable<B> bs)

Zips two iterables into a single iterable that produces pairs.

Type Parameters:

A - LHS type

B - RHS type

Parameters:

as - left values

bs - right values

Returns:

an iterable of pairs, only as long as the shortest input iterable.

Since:

1.1

zip

public static <A,B> java.util.Optional<Pair<A,B>> zip(java.util.Optional<A> oA,
                                                                  java.util.Optional<B> oB)

Zips the two given optionals into an optional of a pair.

Type Parameters:

A - the first type

B - the second type

Parameters:

oA - the first optional

oB - the second optional

Returns:

empty if either or both optionals are empty

Since:

4.6.0

left

public A left()

Accessor method for the left value of the pair.

Returns:

a A object.

right

public B right()

Accessor method for the right value of the pair.q

Returns:

a B object.

swap

public Pair<B,A> swap()

Returns:

a new Pair wth the left and right values swapped.

Since:

6.1

fold

public <R> R fold(java.util.function.BiFunction<? super A,? super B,R> f)

Applies a function to left and right values to produce a single result.

Type Parameters:

R - the result type

Parameters:

f - the function to apply to the values

Returns:

the result of the applied function

Since:

6.1

leftMap

public <AA> Pair<AA,B> leftMap(java.util.function.Function<? super A,AA> fLeft)

Applies a function to the left value to produce a new Pair.

Type Parameters:

AA - The type of the new left value

Parameters:

fLeft - the function to be applied to the left value

Returns:

A new Pair containing the new left value, and the existing right value

Since:

6.1

rightMap

public <BB> Pair<A,BB> rightMap(java.util.function.Function<? super B,BB> fRight)

Applies a function to the right value to produce a new Pair.

Type Parameters:

BB - The type of the new right value

Parameters:

fRight - the function to be applied to the right value

Returns:

A new Pair containing the existing left value, and the new right value

Since:

6.1

bimap

public <AA,BB> Pair<AA,BB> bimap(java.util.function.Function<? super A,? extends AA> fLeft,
                                             java.util.function.Function<? super B,? extends BB> fRight)

Applies functions to each of the left and right values to produce a new pair.

Type Parameters:

AA - the type of the new left value

BB - the type of the new right value

Parameters:

fLeft - the function to be applied to the left value

fRight - the function to be applied to the right value

Returns:

a new Pair containing the new left and right values

Since:

6.1

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object