org.mule.runtime.api.functional

Class Either<L,R>

java.lang.Object

org.mule.runtime.api.functional.Either<L,R>

Type Parameters:

L - the type of the left value

R - the type of the right value

public class Either<L,R>
extends Object

This class allow to represent a type that holds two different values.

Only one value can be present at any given type.

This class can be used as a monad to interact and chain functions to be executed over the possible return values.

Most likely the left type represent an error or failure result and the right value represent a successful result.

Since:

1.3

Method Summary

Modifier and Type	Method and Description
void	apply(Consumer<? super L> leftConsumer, Consumer<? super R> rightConsumer) Receives a Consumer functions for both, the left and right value and applies the one over the value that is present.
void	applyLeft(Consumer<? super L> consumer)
void	applyRight(Consumer<? super R> consumer)
static <L,R> Either<L,R>	empty() Creates an Either that doesn't have any left or right value.
L	getLeft()
R	getRight()
<T> Optional<T>	getValue()
boolean	isLeft()
boolean	isRight()
static <L,R> Either<L,R>	left(L value) Creates an Either with a left value.
static <L,R> Either<L,R>	left(L value, Class<R> rightClass) Creates an Either with a left value and forcing a class for its empty right.
<T> Either<T,R>	mapLeft(Function<? super L,? extends T> func) Allows to execute a function over the left value if it is present
<T> Either<L,T>	mapRight(Function<? super R,? extends T> func) Allows to execute a function over the right value if it is present
<T> T	reduce(Function<? super L,? extends T> leftFunc, Function<? super R,? extends T> rightFunc) Allows to reduce to a single value using left and right functions with the same return type.
static <L,R> Either<L,R>	right(Class<L> leftClass, R value) Creates an Either with a right value and forcing a class for its empty left.
static <L,R> Either<L,R>	right(R value) Creates an Either with a right value.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

empty

public static <L,R> Either<L,R> empty()

Creates an Either that doesn't have any left or right value.

Returns:

a singleton empty Either instance

left

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

Creates an Either with a left value.

Type Parameters:

L - the left value type

R - the right value type

Parameters:

value - the left value

Returns:

the created Either instance

left

public static <L,R> Either<L,R> left(L value,
                                     Class<R> rightClass)

Creates an Either with a left value and forcing a class for its empty right.

This is useful because it avoids the casting afterwards which can clutter the code and affect its readability.

Type Parameters:

L - the left value type

R - the right value type

Parameters:

value - the left value

Returns:

the created Either instance

right

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

Creates an Either with a right value.

Type Parameters:

L - the left value type

R - the right value type

Parameters:

value - the right value

Returns:

the created Either instance

right

public static <L,R> Either<L,R> right(Class<L> leftClass,
                                      R value)

Creates an Either with a right value and forcing a class for its empty left.

This is useful because it avoids the casting afterwards which can clutter the code and affect its readability.

Type Parameters:

L - the left value type

R - the right value type

Parameters:

value - the right value

Returns:

the created Either instance

reduce

public <T> T reduce(Function<? super L,? extends T> leftFunc,
                    Function<? super R,? extends T> rightFunc)

Allows to reduce to a single value using left and right functions with the same return type.

Type Parameters:

T - the return type of the function.

Parameters:

leftFunc - the function to apply to the left value

rightFunc - the function to apply to the left value

Returns:

the result of applying the function on left of right values, or null if none were set.

mapLeft

public <T> Either<T,R> mapLeft(Function<? super L,? extends T> func)

Allows to execute a function over the left value if it is present

Type Parameters:

T - the return type of the function.

Parameters:

func - the function to apply to the left value

Returns:

a new Either created from the result of applying the function.

applyLeft

public void applyLeft(Consumer<? super L> consumer)

applyRight

public void applyRight(Consumer<? super R> consumer)

mapRight

public <T> Either<L,T> mapRight(Function<? super R,? extends T> func)

Allows to execute a function over the right value if it is present

Type Parameters:

T - the return type of the function.

Parameters:

func - the function to apply to the right value

Returns:

a new Either created from the result of applying the function.

apply

public void apply(Consumer<? super L> leftConsumer,
                  Consumer<? super R> rightConsumer)

Receives a Consumer functions for both, the left and right value and applies the one over the value that is present.

Parameters:

leftConsumer - the function to apply to the left value

rightConsumer - the function to apply to the right value

isLeft

public boolean isLeft()

Returns:

true if it holds a value for the left type, false otherwise

isRight

public boolean isRight()

Returns:

true if it holds a value for the right type, false otherwise

getLeft

public L getLeft()

Returns:

the left value

getRight

public R getRight()

Returns:

the right value

getValue

public <T> Optional<T> getValue()

toString

public String toString()

Overrides:

toString in class Object