org.springframework.data.util

Interface Optionals

public interface Optionals

Utility methods to work with Optionals.

Author:

Oliver Gierke, Christoph Strobl

Method Summary

Modifier and Type	Method and Description
static <S,T> Optional<T>	firstNonEmpty(Iterable<S> source, Function<S,Optional<T>> function) Applies the given function to the elements of the source and returns the first non-empty result.
static <S,T> T	firstNonEmpty(Iterable<S> source, Function<S,T> function, T defaultValue) Applies the given function to the elements of the source and returns the first non-empty result.
static <T> Optional<T>	firstNonEmpty(Iterable<Supplier<Optional<T>>> suppliers) Invokes the given Suppliers for Optional results one by one and returns the first non-empty one.
static <T> Optional<T>	firstNonEmpty(Supplier<Optional<T>>... suppliers) Invokes the given Suppliers for Optional results one by one and returns the first non-empty one.
static <T,S> void	ifAllPresent(Optional<T> left, Optional<S> right, BiConsumer<T,S> consumer) Invokes the given BiConsumer if all given Optional are present.
static <T> void	ifPresentOrElse(Optional<T> optional, Consumer<? super T> consumer, Runnable runnable) Invokes the given Consumer if the Optional is present or the Runnable if not.
static boolean	isAnyPresent(Optional<?>... optionals) Returns whether any of the given Optionals is present.
static <T,S,R> Optional<R>	mapIfAllPresent(Optional<T> left, Optional<S> right, BiFunction<T,S,R> function) Maps the values contained in the given Optional if both of them are present.
static <T> Optional<T>	next(Iterator<T> iterator) Returns the next element of the given Iterator or Optional.empty() in case there is no next element.
static <T> Stream<T>	toStream(Optional<? extends T>... optionals) Turns the given Optional into a one-element Stream or an empty one if not present.
static <T,S> Optional<Pair<T,S>>	withBoth(Optional<T> left, Optional<S> right) Returns a Pair if both Optional instances have values or Optional.empty() if one or both are missing.

Method Detail

isAnyPresent

static boolean isAnyPresent(Optional<?>... optionals)

Returns whether any of the given Optionals is present.

Parameters:

optionals - must not be null.

Returns:

toStream

@SafeVarargs
static <T> Stream<T> toStream(Optional<? extends T>... optionals)

Turns the given Optional into a one-element Stream or an empty one if not present.

Parameters:

optionals - must not be null.

Returns:

firstNonEmpty

static <S,T> Optional<T> firstNonEmpty(Iterable<S> source,
                                       Function<S,Optional<T>> function)

Applies the given function to the elements of the source and returns the first non-empty result.

Parameters:

source - must not be null.

function - must not be null.

Returns:

firstNonEmpty

static <S,T> T firstNonEmpty(Iterable<S> source,
                             Function<S,T> function,
                             T defaultValue)

Applies the given function to the elements of the source and returns the first non-empty result.

Parameters:

source - must not be null.

function - must not be null.

Returns:

firstNonEmpty

@SafeVarargs
static <T> Optional<T> firstNonEmpty(Supplier<Optional<T>>... suppliers)

Invokes the given Suppliers for Optional results one by one and returns the first non-empty one.

Parameters:

suppliers - must not be null.

Returns:

firstNonEmpty

static <T> Optional<T> firstNonEmpty(Iterable<Supplier<Optional<T>>> suppliers)

Invokes the given Suppliers for Optional results one by one and returns the first non-empty one.

Parameters:

suppliers - must not be null.

Returns:

next

static <T> Optional<T> next(Iterator<T> iterator)

Returns the next element of the given Iterator or Optional.empty() in case there is no next element.

Parameters:

iterator - must not be null.

Returns:

withBoth

static <T,S> Optional<Pair<T,S>> withBoth(Optional<T> left,
                                          Optional<S> right)

Returns a Pair if both Optional instances have values or Optional.empty() if one or both are missing.

Parameters:

left -

right -

Returns:

ifAllPresent

static <T,S> void ifAllPresent(Optional<T> left,
                               Optional<S> right,
                               BiConsumer<T,S> consumer)

Invokes the given BiConsumer if all given Optional are present.

Parameters:

left - must not be null.

right - must not be null.

consumer - must not be null.

mapIfAllPresent

static <T,S,R> Optional<R> mapIfAllPresent(Optional<T> left,
                                           Optional<S> right,
                                           BiFunction<T,S,R> function)

Maps the values contained in the given Optional if both of them are present.

Parameters:

left - must not be null.

right - must not be null.

function - must not be null.

Returns:

ifPresentOrElse

static <T> void ifPresentOrElse(Optional<T> optional,
                                Consumer<? super T> consumer,
                                Runnable runnable)

Invokes the given Consumer if the Optional is present or the Runnable if not.

Parameters:

optional - must not be null.

consumer - must not be null.

runnable - must not be null.