Package org.linkki.util

Class Optionals

java.lang.Object

org.linkki.util.Optionals

public final class Optionals
extends Object

Utility class for Optional.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Optionals.Either<T>	Wrapper around an Optional that offers Java 9's Optional#or method.

Method Summary

Modifier and Type	Method	Description
static <T> Optionals.Either<T>	either(Optional<T> o)	In anticipation of Java 9 Optional#or.
static <T> void	ifPresentOrElse(Optional<T> optional, Consumer<? super T> action, Runnable emptyAction)	In anticipation of Java 9 Optional#ifPresentOrElse.
static <T> Stream<T>	stream(Optional<T> o)	In anticipation of Java 9 Optional#stream.

Methods inherited from class java.lang.Object

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

Method Detail

ifPresentOrElse

public static <T> void ifPresentOrElse(Optional<T> optional,
                                       Consumer<? super T> action,
                                       Runnable emptyAction)

In anticipation of Java 9 Optional#ifPresentOrElse.

If a value is present in the given optional, performs the given action with the value, otherwise performs the given empty-based action.

Parameters:

optional - an Optional

action - the action to be performed, if a value is present

emptyAction - the empty-based action to be performed, if no value is present

Throws:

NullPointerException - if a value is present and the given action is null, or no value is present and the given empty-based action is null.

stream

public static <T> Stream<T> stream(Optional<T> o)

In anticipation of Java 9 Optional#stream.

If a value is present, returns a sequential Stream containing only that value, otherwise returns an empty Stream.

API Note: This method can be used to transform a Stream of optional elements to a Stream of present value elements:

  
 Stream<Optional<T>> os = .. 
 Stream<T> s = os.flatMap(Optional::stream)
 

Returns:

the optional value as a Stream

either

public static <T> Optionals.Either<T> either(Optional<T> o)

In anticipation of Java 9 Optional#or. Creates an Optionals.Either wrapper around the given Optional on which Optionals.Either.or(Supplier) can be called.