javascalautils

Interface Either<L,R>

Type Parameters:

L - The type for the Left side

R - The type for the Right side

All Known Implementing Classes:

Left, Right

public interface Either<L,R>

Represents a value of one of two possible types.
Instances of Either are either an instance of Left or Right.
This is what is called a disjoint union, meaning that the Either will never contain both types only one of them.
This is the biggest difference from a tuple that would contain both values.
Examples of creating an Either of the type Right.

 
 Either<Object, String> either = new Right<>("Right is not Left");
 
 

Since:

1.1

Author:

Peter Nerg

Method Summary

Modifier and Type	Method and Description
<T> T	fold(java.util.function.Function<L,T> func_left, java.util.function.Function<R,T> func_right) Applies func_left if this is a Left or func_right if this is a Right
default boolean	isLeft() Returnstrue if this instance is Left, else false
boolean	isRight() Returnstrue if this instance is Right, else false.
default LeftProjection<L,R>	left() Returns a LeftProjection for this instance.
default RightProjection<L,R>	right() Returns a RightProjection for this instance.
Either<R,L>	swap() If this is a Left, then return the left value in Right or vice versa.

Method Detail

isRight

boolean isRight()

Returnstrue if this instance is Right, else false.

Returns:

true if this instance is Right.

isLeft

default boolean isLeft()

Returnstrue if this instance is Left, else false

Returns:

true if this instance is Left.

fold

<T> T fold(java.util.function.Function<L,T> func_left,
           java.util.function.Function<R,T> func_right)

Applies func_left if this is a Left or func_right if this is a Right

Type Parameters:

T - The type to return from func_left/func_right

Parameters:

func_left - The function to apply in case this is a Left

func_right - The function to apply in case this is a Right

Returns:

The result from applying either func_left or func_right

right

default RightProjection<L,R> right()

Returns a RightProjection for this instance.

Returns:

The projection

left

default LeftProjection<L,R> left()

Returns a LeftProjection for this instance.

Returns:

The projection

swap

Either<R,L> swap()

If this is a Left, then return the left value in Right or vice versa.

Returns:

The swapped version of this instance