org.apache.flink.types

Class Either<L,R>

java.lang.Object

org.apache.flink.types.Either<L,R>

Type Parameters:

L - the type of Left

R - the type of Right

Direct Known Subclasses:

Either.Left, Either.Right

@Public
 @TypeInfo(value=EitherTypeInfoFactory.class)
public abstract class Either<L,R>
extends Object

This type represents a value of one two possible types, Left or Right (a disjoint union), inspired by Scala's Either type.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Either.Left<L,R> A left value of Either
static class	Either.Right<L,R> A right value of Either

Constructor Summary

Constructors

Constructor and Description
Either()

Method Summary

Modifier and Type	Method and Description
boolean	isLeft()
boolean	isRight()
abstract L	left() Retrieve the Left value of Either.
static <L,R> Either<L,R>	Left(L value) Create a Left value of Either
static <L,R> Either.Left<L,R>	obtainLeft(Either<L,R> input, TypeSerializer<L> leftSerializer) Utility function for EitherSerializer to support object reuse.
static <L,R> Either.Right<L,R>	obtainRight(Either<L,R> input, TypeSerializer<R> rightSerializer) Utility function for EitherSerializer to support object reuse.
abstract R	right() Retrieve the Right value of Either.
static <L,R> Either<L,R>	Right(R value) Create a Right value of Either

Methods inherited from class java.lang.Object

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

Constructor Detail

Either

public Either()

Method Detail

Left

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

Create a Left value of Either

Right

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

Create a Right value of Either

left

public abstract L left()
                throws IllegalStateException

Retrieve the Left value of Either.

Returns:

the Left value

Throws:

IllegalStateException - if called on a Right

right

public abstract R right()
                 throws IllegalStateException

Retrieve the Right value of Either.

Returns:

the Right value

Throws:

IllegalStateException - if called on a Left

isLeft

public final boolean isLeft()

Returns:

true if this is a Left value, false if this is a Right value

isRight

public final boolean isRight()

Returns:

true if this is a Right value, false if this is a Left value

obtainLeft

@Internal
public static <L,R> Either.Left<L,R> obtainLeft(Either<L,R> input,
                                                          TypeSerializer<L> leftSerializer)

Utility function for EitherSerializer to support object reuse. To support object reuse both subclasses of Either contain a reference to an instance of the other type. This method provides access to and initializes the cross-reference.

Type Parameters:

L - the type of Left

R - the type of Right

Parameters:

input - container for Left or Right value

leftSerializer - for creating an instance of the left type

Returns:

input if Left type else input's Left reference

obtainRight

@Internal
public static <L,R> Either.Right<L,R> obtainRight(Either<L,R> input,
                                                            TypeSerializer<R> rightSerializer)

Utility function for EitherSerializer to support object reuse. To support object reuse both subclasses of Either contain a reference to an instance of the other type. This method provides access to and initializes the cross-reference.

Type Parameters:

L - the type of Left

R - the type of Right

Parameters:

input - container for Left or Right value

rightSerializer - for creating an instance of the right type

Returns:

input if Right type else input's Right reference