com.mojang.datafixers.util

Class Either<L,R>

java.lang.Object

com.mojang.datafixers.util.Either<L,R>

Type Parameters:

L - The left type.

R - The right type.

All Implemented Interfaces:

(L|R)

public abstract class Either<L,R>
extends Object

A type which may hold either a value of the left type, or a value of the right type. An Either is a basic sum type, or tagged union.

Type Shape:

"(%0%.|.%1)"

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Either.Instance<R2> The Applicative, Traversable, and CocartesianLike type class instance for Either.
static class	Either.Mu<R> The witness type for Either.

Method Summary

Modifier and Type	Method and Description
<L2> (L2|R)	flatMap((L) -> (L2|R) function) Maps the left value, if it is present, to a new type in an Either.
abstract (L|R)	ifLeft((? super L) -> void consumer) Applies the given callback if the left value is present.
abstract (L|R)	ifRight((? super R) -> void consumer) Applies the given callback if the right value is present.
abstract Optional<L>	left() Gets the left value in an Optional.
static <L,R> (L|R)	left(L value) Constructs an Either with the given left value.
abstract <T> T	map((? super L) -> ? extends T l, (? super R) -> ? extends T r) Maps either the left or the right value, whichever is present, to a common third type.
abstract <C,D> (C|D)	mapBoth((? super L) -> ? extends C f1, (? super R) -> ? extends D f2) Maps either the left or the right value, whichever is present, to another type.
<T> (T|R)	mapLeft((? super L) -> ? extends T l) Maps the left value, if present, to another type.
<T> (L|T)	mapRight((? super R) -> ? extends T l) Maps the right value, if present, to another type.
L	orThrow() Returns the left value if it is present, or throws an exception if it is not.
abstract Optional<R>	right() Gets the right value in an Optional.
static <L,R> (L|R)	right(R value) Constructs an Either with the given right value.
(R|L)	swap() Swaps the value in this Either, such that the left value becomes the right value and visa-versa.
static <L,R> (L|R)	unbox((L|R) box) Thunk method to cast an applied Either.Mu to an Either.

Methods inherited from class java.lang.Object

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

Method Detail

unbox

public static <L,R> (L|R) unbox((L|R) box)

Thunk method to cast an applied Either.Mu to an Either.

Type Parameters:

L - The left type.

R - The right type.

Parameters:

box - The boxed either.

Returns:

The unboxed either.

mapBoth

public abstract <C,D> (C|D) mapBoth((? super L) -> ? extends C f1,
                                    (? super R) -> ? extends D f2)

Maps either the left or the right value, whichever is present, to another type.

Type Parameters:

C - The new left type.

D - The new right type.

Parameters:

f1 - A mapping function for the left type.

f2 - A mapping function for the right type.

Returns:

An Either containing the new left or right value.

map

public abstract <T> T map((? super L) -> ? extends T l,
                          (? super R) -> ? extends T r)

Maps either the left or the right value, whichever is present, to a common third type.

Type Parameters:

T - The common type to map to.

Parameters:

l - A mapping function for the left type.

r - A mapping function for the right type.

Returns:

The result of mapping the left or right value.

ifLeft

public abstract (L|R) ifLeft((? super L) -> void consumer)

Applies the given callback if the left value is present.

Parameters:

consumer - A callback to apply to the left value.

Returns:

This instance.

ifRight

public abstract (L|R) ifRight((? super R) -> void consumer)

Applies the given callback if the right value is present.

Parameters:

consumer - A callback to apply to the right value.

Returns:

This instance.

left

public abstract Optional<L> left()

Gets the left value in an Optional.

right

public abstract Optional<R> right()

Gets the right value in an Optional.

mapLeft

public <T> (T|R) mapLeft((? super L) -> ? extends T l)

Maps the left value, if present, to another type.

Type Parameters:

T - The new left type.

Parameters:

l - A mapping function for the left value.

Returns:

An Either which may contain the mapped left value.

mapRight

public <T> (L|T) mapRight((? super R) -> ? extends T l)

Maps the right value, if present, to another type.

Type Parameters:

T - The new right type.

Parameters:

l - A mapping function for the right value.

Returns:

An Either which may contain the mapped right value.

left

public static <L,R> (L|R) left(L value)

Constructs an Either with the given left value.

Type Parameters:

L - The left type.

R - The right type.

Parameters:

value - The left value.

Returns:

An Either containing the given value.

right

public static <L,R> (L|R) right(R value)

Constructs an Either with the given right value.

Type Parameters:

L - The left type.

R - The right type.

Parameters:

value - The right value.

Returns:

An Either containing the given value.

orThrow

public L orThrow()

Returns the left value if it is present, or throws an exception if it is not. If the right value is an instance of Throwable, the thrown exception has that value as its cause.

Returns:

The left value, if present.

Throws:

RuntimeException - If the left value is not present.

swap

public (R|L) swap()

Swaps the value in this Either, such that the left value becomes the right value and visa-versa.

flatMap

public <L2> (L2|R) flatMap((L) -> (L2|R) function)

Maps the left value, if it is present, to a new type in an Either.

Type Parameters:

L2 - The new left type.

Parameters:

function - A mapping function for the left value.

Returns:

An Either that is the result of the mapping.