Module io.helidon.common.reactive

Package io.helidon.common.reactive

Interface Single<T>

Type Parameters:

T - item type

All Superinterfaces:

Awaitable<T>, CompletionStage<T>, Flow.Publisher<T>, Subscribable<T>

All Known Implementing Classes:

CompletionSingle

public interface Single<T>
extends Subscribable<T>, CompletionStage<T>, Awaitable<T>

Represents a Flow.Publisher that may: signal one item then completes, complete without an item or signal an error.

See Also:

• Multi

Method Summary

Modifier and Type	Method	Description
CompletionAwaitable<Void>	acceptEither(CompletionStage<? extends T> other, Consumer<? super T> action)
CompletionAwaitable<Void>	acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action)
CompletionAwaitable<Void>	acceptEitherAsync(CompletionStage<? extends T> other, Consumer<? super T> action, Executor executor)
<U> CompletionAwaitable<U>	applyToEither(CompletionStage<? extends T> other, Function<? super T,U> fn)
<U> CompletionAwaitable<U>	applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T,U> fn)
<U> CompletionAwaitable<U>	applyToEitherAsync(CompletionStage<? extends T> other, Function<? super T,U> fn, Executor executor)
default Single<T>	cancel()	Cancel upstream.
default <U> Single<U>	compose(Function<? super Single<T>,? extends Single<? extends U>> composer)	Apply the given composer function to the current Single instance and return the Single returned by this function.
static <T> Single<T>	create(Single<T> single)	Create a Single instance that publishes the first and only item received from the given Single.
static <T> Single<T>	create(CompletionStage<T> completionStage)	Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.
static <T> Single<T>	create(CompletionStage<T> completionStage, boolean nullMeansEmpty)	Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.
static <T> Single<T>	create(Flow.Publisher<T> source)	Create a Single instance that publishes the first and only item received from the given publisher.
static <T> Single<T>	create(Supplier<? extends T> supplier)	Create a Single instance that publishes result of the given supplier to its subscriber(s).
default Single<T>	defaultIfEmpty(Supplier<? extends T> supplier)	Signals the default item supplied by specified supplier if the upstream is empty.
default Single<T>	defaultIfEmpty(T defaultItem)	Signals the default item if the upstream is empty.
static <T> Single<T>	defer(Supplier<? extends Single<? extends T>> supplier)	Call the given supplier function for each individual downstream Subscriber to return a Flow.Publisher to subscribe to.
static <T> Single<T>	empty()	Get a Single instance that completes immediately.
static <T> Single<T>	error(Throwable error)	Create a Single instance that reports the given given exception to its subscriber(s).
CompletionAwaitable<T>	exceptionally(Function<Throwable,? extends T> fn)
CompletionAwaitable<T>	exceptionallyAccept(Consumer<Throwable> consumer)	Returns a new CompletionAwaitable that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied consumer.
default <U> Multi<U>	flatMap(Function<? super T,? extends Flow.Publisher<? extends U>> mapper)	Map this Single instance to a publisher using the given Mapper.
default <U> Single<U>	flatMapCompletionStage(Function<? super T,? extends CompletionStage<? extends U>> mapper)	Transforms item with supplied function and flatten resulting CompletionStage result to downstream.
default <U> Multi<U>	flatMapIterable(Function<? super T,? extends Iterable<? extends U>> mapper)	Maps the single upstream value into an Iterable and relays its items to the downstream.
default <U> Single<U>	flatMapOptional(Function<? super T,Optional<? extends U>> mapper)	Transform item with supplied function and flatten resulting Optional to downstream as Single with its value as item if present or empty Single.
default <U> Single<U>	flatMapSingle(Function<? super T,? extends Single<? extends U>> mapper)	Transforms item with supplied function and flatten resulting Single to downstream.
default CompletionAwaitable<Void>	forSingle(Consumer<T> consumer)	Terminal stage, invokes provided consumer when Single is completed.
static <T> Single<T>	from(Single<T> single)	Deprecated. use create(io.helidon.common.reactive.Single) instead
static <T> Single<T>	from(CompletionStage<T> completionStage)	Deprecated. use create(java.util.concurrent.CompletionStage) instead
static <T> Single<T>	from(CompletionStage<T> completionStage, boolean nullMeansEmpty)	Deprecated. use create(java.util.concurrent.CompletionStage, boolean) instead
static <T> Single<T>	from(Flow.Publisher<T> source)	Deprecated. use create(java.util.concurrent.Flow.Publisher) instead
default T	get()	Short-hand for toFuture().toCompletableFuture().get().
default T	get(long timeout, TimeUnit unit)	Short-hand for toFuture().toCompletableFuture().get().
<U> CompletionAwaitable<U>	handle(BiFunction<? super T,Throwable,? extends U> fn)
<U> CompletionAwaitable<U>	handleAsync(BiFunction<? super T,Throwable,? extends U> fn)
<U> CompletionAwaitable<U>	handleAsync(BiFunction<? super T,Throwable,? extends U> fn, Executor executor)
default Single<T>	ifEmpty(Runnable ifEmpty)	Executes given Runnable when stream is finished without value(empty stream).
default CompletionAwaitable<Void>	ignoreElement()	Terminal stage, ignore onNext signals, only onComplete and onError signals are propagated.
static <T> Single<T>	just(T item)	Create a Single instance that publishes the given item to its subscriber(s).
default Single<T>	log()	Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.
default Single<T>	log(Level level)	Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.
default Single<T>	log(Level level, boolean trace)	Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.
default Single<T>	log(Level level, String loggerName)	Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.
default <U> Single<U>	map(Function<? super T,? extends U> mapper)	Map this Single instance to a new Single of another type using the given Function.
static <T> Single<T>	never()	Get a Single instance that never completes.
default Single<T>	observeOn(Executor executor)	Re-emit the upstream's signals to the downstream on the given executor's thread.
default Single<T>	onCancel(Runnable onCancel)	Executes given Runnable when a cancel signal is received.
default Single<T>	onComplete(Runnable onComplete)	Executes given Runnable when onComplete signal is received.
default Multi<T>	onCompleteResume(T item)	Resume stream from single item if onComplete signal is intercepted.
default Multi<T>	onCompleteResumeWith(Flow.Publisher<? extends T> publisher)	Resume stream from supplied publisher if onComplete signal is intercepted.
default Single<T>	onCompleteResumeWithSingle(Function<Optional<T>,? extends Single<? extends T>> onComplete)	Resume stream with supplied single if onComplete signal is intercepted.
default Single<T>	onError(Consumer<? super Throwable> onErrorConsumer)	Executes given Consumer when onError signal is received.
default Single<T>	onErrorResume(Function<? super Throwable,? extends T> onError)	Function providing one item to be submitted as onNext in case of onError signal is received.
default Multi<T>	onErrorResumeWith(Function<? super Throwable,? extends Flow.Publisher<? extends T>> onError)	Resume stream from supplied publisher if onError signal is intercepted.
default Single<T>	onErrorResumeWithSingle(Function<? super Throwable,? extends Single<? extends T>> onError)	Resume stream from supplied publisher if onError signal is intercepted.
default Single<T>	onTerminate(Runnable onTerminate)	Executes given Runnable when any of signals onComplete, onCancel or onError is received.
default Single<T>	peek(Consumer<? super T> consumer)	Invoke provided consumer for the item in stream.
default Single<T>	retry(long count)	Retry a failing upstream at most the given number of times before giving up.
default Single<T>	retry(BiPredicate<? super Throwable,? super Long> predicate)	Retry a failing upstream if the predicate returns true.
default <U> Single<T>	retryWhen(BiFunction<? super Throwable,? super Long,? extends Flow.Publisher<U>> whenFunction)	Retry a failing upstream when the given function returns a publisher that signals an item.
CompletionAwaitable<Void>	runAfterBoth(CompletionStage<?> other, Runnable action)
CompletionAwaitable<Void>	runAfterBothAsync(CompletionStage<?> other, Runnable action)
CompletionAwaitable<Void>	runAfterBothAsync(CompletionStage<?> other, Runnable action, Executor executor)
CompletionAwaitable<Void>	runAfterEither(CompletionStage<?> other, Runnable action)
CompletionAwaitable<Void>	runAfterEitherAsync(CompletionStage<?> other, Runnable action)
CompletionAwaitable<Void>	runAfterEitherAsync(CompletionStage<?> other, Runnable action, Executor executor)
default Single<T>	switchIfEmpty(Single<T> other)	Switch to the other Single if the upstream is empty.
default <U> Single<T>	takeUntil(Flow.Publisher<U> other)	Relay upstream items until the other source signals an item or completes.
CompletionAwaitable<Void>	thenAccept(Consumer<? super T> action)
CompletionAwaitable<Void>	thenAcceptAsync(Consumer<? super T> action)
CompletionAwaitable<Void>	thenAcceptAsync(Consumer<? super T> action, Executor executor)
<U> CompletionAwaitable<Void>	thenAcceptBoth(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)
<U> CompletionAwaitable<Void>	thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action)
<U> CompletionAwaitable<Void>	thenAcceptBothAsync(CompletionStage<? extends U> other, BiConsumer<? super T,? super U> action, Executor executor)
<U> CompletionAwaitable<U>	thenApply(Function<? super T,? extends U> fn)
<U> CompletionAwaitable<U>	thenApplyAsync(Function<? super T,? extends U> fn)
<U> CompletionAwaitable<U>	thenApplyAsync(Function<? super T,? extends U> fn, Executor executor)
<U, V> CompletionAwaitable<V>	thenCombine(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn)
<U, V> CompletionAwaitable<V>	thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn)
<U, V> CompletionAwaitable<V>	thenCombineAsync(CompletionStage<? extends U> other, BiFunction<? super T,? super U,? extends V> fn, Executor executor)
<U> CompletionAwaitable<U>	thenCompose(Function<? super T,? extends CompletionStage<U>> fn)
<U> CompletionAwaitable<U>	thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn)
<U> CompletionAwaitable<U>	thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn, Executor executor)
CompletionAwaitable<Void>	thenRun(Runnable action)
CompletionAwaitable<Void>	thenRunAsync(Runnable action)
CompletionAwaitable<Void>	thenRunAsync(Runnable action, Executor executor)
default Single<T>	timeout(long timeout, TimeUnit unit, ScheduledExecutorService executor)	Signals a TimeoutException if the upstream doesn't signal an item, error or completion within the specified time.
default Single<T>	timeout(long timeout, TimeUnit unit, ScheduledExecutorService executor, Single<T> fallback)	Switches to a fallback single if the upstream doesn't signal an item, error or completion within the specified time.
static Single<Long>	timer(long time, TimeUnit unit, ScheduledExecutorService executor)	Signal 0L and complete the sequence after the given time elapsed.
default <U> U	to(Function<? super Single<T>,? extends U> converter)	Apply the given converter function to the current Single instance and return the value returned by this function.
default Single<Optional<T>>	toOptionalSingle()	Exposes this Single instance as a Single with Optional<T> return type of the asynchronous operation.
default CompletionStage<T>	toStage()	Exposes this Single instance as a CompletionStage.
default CompletionStage<T>	toStage(boolean completeWithoutValue)	Exposes this Single instance as a CompletionStage.
CompletionAwaitable<T>	whenComplete(BiConsumer<? super T,? super Throwable> action)
CompletionAwaitable<T>	whenCompleteAsync(BiConsumer<? super T,? super Throwable> action)
CompletionAwaitable<T>	whenCompleteAsync(BiConsumer<? super T,? super Throwable> action, Executor executor)

Methods inherited from interface io.helidon.common.reactive.Awaitable

await, await, await, toCompletableFuture

Methods inherited from interface java.util.concurrent.CompletionStage

exceptionallyAsync, exceptionallyAsync, exceptionallyCompose, exceptionallyComposeAsync, exceptionallyComposeAsync, toCompletableFuture

Methods inherited from interface java.util.concurrent.Flow.Publisher

subscribe

Methods inherited from interface io.helidon.common.reactive.Subscribable

subscribe, subscribe, subscribe, subscribe

Method Details

defer

static <T> Single<T> defer(Supplier<? extends Single<? extends T>> supplier)

Call the given supplier function for each individual downstream Subscriber to return a Flow.Publisher to subscribe to.

Type Parameters:

T - the element type of the sequence

Parameters:

supplier - the callback to return a Flow.Publisher for each Subscriber

Returns:

Multi

Throws:

NullPointerException - if supplier is null

empty

static <T> Single<T> empty()

Get a Single instance that completes immediately.

Type Parameters:

T - item type

Returns:

Single

error

static <T> Single<T> error(Throwable error)

Create a Single instance that reports the given given exception to its subscriber(s). The exception is reported by invoking Flow.Subscriber.onError(java.lang.Throwable) when Flow.Publisher.subscribe(Subscriber) is called.

Type Parameters:

T - item type

Parameters:

error - exception to hold

Returns:

Single

Throws:

NullPointerException - if error is null

from

@Deprecated
static <T> Single<T> from(CompletionStage<T> completionStage)

Deprecated.

use create(java.util.concurrent.CompletionStage) instead

Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.

A null result from the CompletionStage will yield a NullPointerException signal.

Type Parameters:

T - the element type of the stage and result

Parameters:

completionStage - the CompletionStage to

Returns:

Single

See Also:

• create(CompletionStage, boolean)

from

@Deprecated
static <T> Single<T> from(CompletionStage<T> completionStage,
 boolean nullMeansEmpty)

Deprecated.

use create(java.util.concurrent.CompletionStage, boolean) instead

Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.

Type Parameters:

T - the element type of the stage and result

Parameters:

completionStage - the CompletionStage to

nullMeansEmpty - if true, a null result is interpreted to be an empty sequence if false, the resulting sequence fails with NullPointerException

Returns:

Single

from

@Deprecated
static <T> Single<T> from(Flow.Publisher<T> source)

Deprecated.

use create(java.util.concurrent.Flow.Publisher) instead

Create a Single instance that publishes the first and only item received from the given publisher. Note that if the publisher publishes more than one item, the resulting Single will hold an error. Use Multi.first() instead in order to get the first item of a publisher that may publish more than one item.

Type Parameters:

T - item type

Parameters:

source - source publisher

Returns:

Single

Throws:

NullPointerException - if source is null

from

@Deprecated
static <T> Single<T> from(Single<T> single)

Deprecated.

use create(io.helidon.common.reactive.Single) instead

Create a Single instance that publishes the first and only item received from the given Single.

Type Parameters:

T - item type

Parameters:

single - source Single publisher

Returns:

Single

Throws:

NullPointerException - if source is null

create

static <T> Single<T> create(CompletionStage<T> completionStage)

Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.

A null result from the CompletionStage will yield a NullPointerException signal.

Type Parameters:

T - the element type of the stage and result

Parameters:

completionStage - the CompletionStage to

Returns:

Single

See Also:

• create(CompletionStage, boolean)

create

static <T> Single<T> create(CompletionStage<T> completionStage,
 boolean nullMeansEmpty)

Wrap a CompletionStage into a Multi and signal its outcome non-blockingly.

Type Parameters:

T - the element type of the stage and result

Parameters:

completionStage - the CompletionStage to

nullMeansEmpty - if true, a null result is interpreted to be an empty sequence if false, the resulting sequence fails with NullPointerException

Returns:

Single

create

static <T> Single<T> create(Flow.Publisher<T> source)

Create a Single instance that publishes the first and only item received from the given publisher. Note that if the publisher publishes more than one item, the resulting Single will hold an error. Use Multi.first() instead in order to get the first item of a publisher that may publish more than one item.

Type Parameters:

T - item type

Parameters:

source - source publisher

Returns:

Single

Throws:

NullPointerException - if source is null

create

static <T> Single<T> create(Single<T> single)

Create a Single instance that publishes the first and only item received from the given Single.

Type Parameters:

T - item type

Parameters:

single - source Single publisher

Returns:

Single

Throws:

NullPointerException - if source is null

just

static <T> Single<T> just(T item)

Create a Single instance that publishes the given item to its subscriber(s).

Type Parameters:

T - item type

Parameters:

item - item to publish

Returns:

Single

Throws:

NullPointerException - if item is null

create

static <T> Single<T> create(Supplier<? extends T> supplier)

Create a Single instance that publishes result of the given supplier to its subscriber(s).

Type Parameters:

T - item type

Parameters:

supplier - item supplier to publish

Returns:

Single

Throws:

NullPointerException - if item is null

never

static <T> Single<T> never()

Get a Single instance that never completes.

Type Parameters:

T - item type

Returns:

Single

timer

static Single<Long> timer(long time,
 TimeUnit unit,
 ScheduledExecutorService executor)

Signal 0L and complete the sequence after the given time elapsed.

Parameters:

time - the time to wait before signaling 0L and completion

unit - the unit of time

executor - the executor to run the waiting on

Returns:

Single

Throws:

NullPointerException - if unit or executor is null

to

default <U> U to(Function<? super Single<T>,? extends U> converter)

Apply the given converter function to the current Single instance and return the value returned by this function.

Note that the converter function is executed upon calling this method immediately and not when the resulting sequence gets subscribed to.

Type Parameters:

U - the output type

Parameters:

converter - the function that receives the current Single instance and should return a value to be returned by the method

Returns:

the value returned by the function

Throws:

NullPointerException - if converter is null

compose

default <U> Single<U> compose(Function<? super Single<T>,? extends Single<? extends U>> composer)

Apply the given composer function to the current Single instance and return the Single returned by this function.

Note that the composer function is executed upon calling this method immediately and not when the resulting sequence gets subscribed to.

Type Parameters:

U - the output element type

Parameters:

composer - the function that receives the current Single instance and should return a Single to be returned by the method

Returns:

Single

Throws:

NullPointerException - if composer is null

defaultIfEmpty

default Single<T> defaultIfEmpty(T defaultItem)

Signals the default item if the upstream is empty.

Specified by:

defaultIfEmpty in interface Subscribable<T>

Parameters:

defaultItem - the item to signal if the upstream is empty

Returns:

Single

Throws:

NullPointerException - if defaultItem is null

defaultIfEmpty

default Single<T> defaultIfEmpty(Supplier<? extends T> supplier)

Signals the default item supplied by specified supplier if the upstream is empty.

Specified by:

defaultIfEmpty in interface Subscribable<T>

Parameters:

supplier - of the default value

Returns:

Multi

Throws:

NullPointerException - if supplier is null

flatMap

default <U> Multi<U> flatMap(Function<? super T,? extends Flow.Publisher<? extends U>> mapper)

Map this Single instance to a publisher using the given Mapper.

Specified by:

flatMap in interface Subscribable<T>

Type Parameters:

U - mapped items type

Parameters:

mapper - mapper

Returns:

Publisher

Throws:

NullPointerException - if mapper is null

flatMapIterable

default <U> Multi<U> flatMapIterable(Function<? super T,? extends Iterable<? extends U>> mapper)

Maps the single upstream value into an Iterable and relays its items to the downstream.

Specified by:

flatMapIterable in interface Subscribable<T>

Type Parameters:

U - the result type

Parameters:

mapper - the function that receives the single upstream value and should return an Iterable instance

Returns:

Multi

Throws:

NullPointerException - if mapper is null

flatMapSingle

default <U> Single<U> flatMapSingle(Function<? super T,? extends Single<? extends U>> mapper)

Transforms item with supplied function and flatten resulting Single to downstream.

Type Parameters:

U - mapped items type

Parameters:

mapper - mapper

Returns:

Single

Throws:

NullPointerException - if mapper is null

flatMapCompletionStage

default <U> Single<U> flatMapCompletionStage(Function<? super T,? extends CompletionStage<? extends U>> mapper)

Transforms item with supplied function and flatten resulting CompletionStage result to downstream. As reactive streams forbids null values, CompletionStage result is mapped to Optional.

Type Parameters:

U - mapped items type

Parameters:

mapper - mapper

Returns:

Single

Throws:

NullPointerException - if mapper is null

flatMapOptional

default <U> Single<U> flatMapOptional(Function<? super T,Optional<? extends U>> mapper)

Transform item with supplied function and flatten resulting Optional to downstream as Single with its value as item if present or empty Single.

Type Parameters:

U - mapped item type

Parameters:

mapper - mapper

Returns:

Single

Throws:

NullPointerException - if mapper is null

map

default <U> Single<U> map(Function<? super T,? extends U> mapper)

Map this Single instance to a new Single of another type using the given Function.

Specified by:

map in interface Subscribable<T>

Type Parameters:

U - mapped item type

Parameters:

mapper - mapper

Returns:

Single

Throws:

NullPointerException - if mapper is null

observeOn

default Single<T> observeOn(Executor executor)

Re-emit the upstream's signals to the downstream on the given executor's thread.

Specified by:

observeOn in interface Subscribable<T>

Parameters:

executor - the executor to signal the downstream from.

Returns:

Single

Throws:

NullPointerException - if executor is null

onCancel

default Single<T> onCancel(Runnable onCancel)

Executes given Runnable when a cancel signal is received.

Specified by:

onCancel in interface Subscribable<T>

Parameters:

onCancel - Runnable to be executed.

Returns:

Single

onComplete

default Single<T> onComplete(Runnable onComplete)

Executes given Runnable when onComplete signal is received.

Specified by:

onComplete in interface Subscribable<T>

Parameters:

onComplete - Runnable to be executed.

Returns:

Single

onError

default Single<T> onError(Consumer<? super Throwable> onErrorConsumer)

Executes given Consumer when onError signal is received.

Specified by:

onError in interface Subscribable<T>

Parameters:

onErrorConsumer - Consumer to be executed.

Returns:

Single

onErrorResume

default Single<T> onErrorResume(Function<? super Throwable,? extends T> onError)

Function providing one item to be submitted as onNext in case of onError signal is received.

Specified by:

onErrorResume in interface Subscribable<T>

Parameters:

onError - Function receiving Throwable as argument and producing one item to resume stream with.

Returns:

Single

onErrorResumeWithSingle

default Single<T> onErrorResumeWithSingle(Function<? super Throwable,? extends Single<? extends T>> onError)

Resume stream from supplied publisher if onError signal is intercepted.

Parameters:

onError - supplier of new stream publisher

Returns:

Single

onErrorResumeWith

default Multi<T> onErrorResumeWith(Function<? super Throwable,? extends Flow.Publisher<? extends T>> onError)

Resume stream from supplied publisher if onError signal is intercepted.

Specified by:

onErrorResumeWith in interface Subscribable<T>

Parameters:

onError - supplier of new stream publisher

Returns:

Single

onCompleteResume

default Multi<T> onCompleteResume(T item)

Resume stream from single item if onComplete signal is intercepted. Effectively do an append to the stream.

Specified by:

onCompleteResume in interface Subscribable<T>

Parameters:

item - one item to resume stream with

Returns:

Multi

onCompleteResumeWith

default Multi<T> onCompleteResumeWith(Flow.Publisher<? extends T> publisher)

Resume stream from supplied publisher if onComplete signal is intercepted.

Specified by:

onCompleteResumeWith in interface Subscribable<T>

Parameters:

publisher - new stream publisher

Returns:

Multi

onCompleteResumeWithSingle

default Single<T> onCompleteResumeWithSingle(Function<Optional<T>,? extends Single<? extends T>> onComplete)

Resume stream with supplied single if onComplete signal is intercepted.

Parameters:

onComplete - function for supplying new Single with optional upstream value as a parameter

Returns:

Single

onTerminate

default Single<T> onTerminate(Runnable onTerminate)

Executes given Runnable when any of signals onComplete, onCancel or onError is received.

Specified by:

onTerminate in interface Subscribable<T>

Parameters:

onTerminate - Runnable to be executed.

Returns:

Single

ifEmpty

default Single<T> ifEmpty(Runnable ifEmpty)

Executes given Runnable when stream is finished without value(empty stream).

Parameters:

ifEmpty - Runnable to be executed.

Returns:

Multi

peek

default Single<T> peek(Consumer<? super T> consumer)

Invoke provided consumer for the item in stream.

Specified by:

peek in interface Subscribable<T>

Parameters:

consumer - consumer to be invoked

Returns:

Single

log

default Single<T> log()

Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.

Returns:

Multi

log

default Single<T> log(Level level)

Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.

Parameters:

level - a logging level value

Returns:

Multi

log

default Single<T> log(Level level,
 String loggerName)

Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.

Parameters:

level - a logging level value

loggerName - custom logger name

Returns:

Multi

log

default Single<T> log(Level level,
 boolean trace)

Log all signals onSubscribe, onNext, onError, onComplete, cancel and request coming to and from preceding operator.

Enabled trace option has a negative impact on performance and should NOT be used in production.

Parameters:

level - a logging level value

trace - if true position of operator is looked up from stack and logged

Returns:

Multi

retry

default Single<T> retry(long count)

Retry a failing upstream at most the given number of times before giving up.

Specified by:

retry in interface Subscribable<T>

Parameters:

count - the number of times to retry; 0 means no retry at all

Returns:

Single

Throws:

IllegalArgumentException - if count is negative

See Also:

• retryWhen(BiFunction)

retry

default Single<T> retry(BiPredicate<? super Throwable,? super Long> predicate)

Retry a failing upstream if the predicate returns true.

Specified by:

retry in interface Subscribable<T>

Parameters:

predicate - the predicate that receives the latest failure Throwable the number of times the retry happened so far (0-based) and should return true to retry the upstream again or false to signal the latest failure

Returns:

Single

Throws:

NullPointerException - if predicate is null

See Also:

• retryWhen(BiFunction)

retryWhen

default <U> Single<T> retryWhen(BiFunction<? super Throwable,? super Long,? extends Flow.Publisher<U>> whenFunction)

Retry a failing upstream when the given function returns a publisher that signals an item.

If the publisher returned by the function completes, the repetition stops and this Single is completed as empty. If the publisher signals an error, the repetition stops and this Single will signal this error.

Specified by:

retryWhen in interface Subscribable<T>

Type Parameters:

U - the element type of the retry-signal sequence

Parameters:

whenFunction - the function that receives the latest failure Throwable the number of times the retry happened so far (0-based) and should return a Flow.Publisher that should signal an item to retry again, complete to stop and complete this Single or signal an error to have this Single emit that error as well.

Returns:

Single

Throws:

NullPointerException - if whenFunction is null

switchIfEmpty

default Single<T> switchIfEmpty(Single<T> other)

Switch to the other Single if the upstream is empty.

Parameters:

other - the Single to switch to if the upstream is empty.

Returns:

Single

Throws:

NullPointerException - if other is null

takeUntil

default <U> Single<T> takeUntil(Flow.Publisher<U> other)

Relay upstream items until the other source signals an item or completes.

Specified by:

takeUntil in interface Subscribable<T>

Type Parameters:

U - the element type of the other sequence

Parameters:

other - the other sequence to signal the end of the main sequence

Returns:

Single

Throws:

NullPointerException - if other is null

timeout

default Single<T> timeout(long timeout,
 TimeUnit unit,
 ScheduledExecutorService executor)

Signals a TimeoutException if the upstream doesn't signal an item, error or completion within the specified time.

Specified by:

timeout in interface Subscribable<T>

Parameters:

timeout - the time to wait for the upstream to signal

unit - the time unit

executor - the executor to use for waiting for the upstream signal

Returns:

Single

Throws:

NullPointerException - if unit or executor is null

timeout

default Single<T> timeout(long timeout,
 TimeUnit unit,
 ScheduledExecutorService executor,
 Single<T> fallback)

Switches to a fallback single if the upstream doesn't signal an item, error or completion within the specified time.

Parameters:

timeout - the time to wait for the upstream to signal

unit - the time unit

executor - the executor to use for waiting for the upstream signal

fallback - the Single to switch to if the upstream doesn't signal in time

Returns:

Single

Throws:

NullPointerException - if unit, executor or fallback is null

get

default T get()
       throws InterruptedException,
ExecutionException

Short-hand for toFuture().toCompletableFuture().get().

Returns:

T

Throws:

InterruptedException - if the current thread was interrupted while waiting

ExecutionException - if the future completed exceptionally

get

default T get(long timeout,
 TimeUnit unit)
       throws InterruptedException,
ExecutionException,
TimeoutException

Short-hand for toFuture().toCompletableFuture().get().

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

T

Throws:

InterruptedException - if the current thread was interrupted while waiting

ExecutionException - if the future completed exceptionally

TimeoutException - if the wait timed out

toOptionalSingle

default Single<Optional<T>> toOptionalSingle()

Exposes this Single instance as a Single with Optional<T> return type of the asynchronous operation. If this Single completes without a value, the resulting Single completes with an empty Optional.

Returns:

CompletionStage

toStage

default CompletionStage<T> toStage()

Exposes this Single instance as a CompletionStage. Note that if this Single completes without a value, the resulting CompletionStage will be completed exceptionally with an IllegalStateException

Returns:

CompletionStage

toStage

default CompletionStage<T> toStage(boolean completeWithoutValue)

Exposes this Single instance as a CompletionStage. Note that if this Single completes without a value and completeWithoutValue is set to false, the resulting CompletionStage will be completed exceptionally with an IllegalStateException

Parameters:

completeWithoutValue - Allow completion without a value.

Returns:

CompletionStage

forSingle

default CompletionAwaitable<Void> forSingle(Consumer<T> consumer)

Terminal stage, invokes provided consumer when Single is completed.

Parameters:

consumer - consumer to be invoked

Returns:

CompletionStage completed when the stream terminates

ignoreElement

default CompletionAwaitable<Void> ignoreElement()

Terminal stage, ignore onNext signals, only onComplete and onError signals are propagated.

Returns:

CompletionStage completed when the stream terminates

cancel

default Single<T> cancel()

Cancel upstream.

Returns:

new Single for eventually received single value.

thenApply

<U> CompletionAwaitable<U> thenApply(Function<? super T,? extends U> fn)

Specified by:

thenApply in interface CompletionStage<T>

thenApplyAsync

<U> CompletionAwaitable<U> thenApplyAsync(Function<? super T,? extends U> fn)

Specified by:

thenApplyAsync in interface CompletionStage<T>

thenApplyAsync

<U> CompletionAwaitable<U> thenApplyAsync(Function<? super T,? extends U> fn,
 Executor executor)

Specified by:

thenApplyAsync in interface CompletionStage<T>

thenAccept

CompletionAwaitable<Void> thenAccept(Consumer<? super T> action)

Specified by:

thenAccept in interface CompletionStage<T>

thenAcceptAsync

CompletionAwaitable<Void> thenAcceptAsync(Consumer<? super T> action)

Specified by:

thenAcceptAsync in interface CompletionStage<T>

thenAcceptAsync

CompletionAwaitable<Void> thenAcceptAsync(Consumer<? super T> action,
 Executor executor)

Specified by:

thenAcceptAsync in interface CompletionStage<T>

thenRun

CompletionAwaitable<Void> thenRun(Runnable action)

Specified by:

thenRun in interface CompletionStage<T>

thenRunAsync

CompletionAwaitable<Void> thenRunAsync(Runnable action)

Specified by:

thenRunAsync in interface CompletionStage<T>

thenRunAsync

CompletionAwaitable<Void> thenRunAsync(Runnable action,
 Executor executor)

Specified by:

thenRunAsync in interface CompletionStage<T>

thenCombine

<U,
V> CompletionAwaitable<V> thenCombine(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn)

Specified by:

thenCombine in interface CompletionStage<T>

thenCombineAsync

<U,
V> CompletionAwaitable<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn)

Specified by:

thenCombineAsync in interface CompletionStage<T>

thenCombineAsync

<U,
V> CompletionAwaitable<V> thenCombineAsync(CompletionStage<? extends U> other,
 BiFunction<? super T,? super U,? extends V> fn,
 Executor executor)

Specified by:

thenCombineAsync in interface CompletionStage<T>

thenAcceptBoth

<U> CompletionAwaitable<Void> thenAcceptBoth(CompletionStage<? extends U> other,
 BiConsumer<? super T,? super U> action)

Specified by:

thenAcceptBoth in interface CompletionStage<T>

thenAcceptBothAsync

<U> CompletionAwaitable<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
 BiConsumer<? super T,? super U> action)

Specified by:

thenAcceptBothAsync in interface CompletionStage<T>

thenAcceptBothAsync

<U> CompletionAwaitable<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,
 BiConsumer<? super T,? super U> action,
 Executor executor)

Specified by:

thenAcceptBothAsync in interface CompletionStage<T>

runAfterBoth

CompletionAwaitable<Void> runAfterBoth(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterBoth in interface CompletionStage<T>

runAfterBothAsync

CompletionAwaitable<Void> runAfterBothAsync(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterBothAsync in interface CompletionStage<T>

runAfterBothAsync

CompletionAwaitable<Void> runAfterBothAsync(CompletionStage<?> other,
 Runnable action,
 Executor executor)

Specified by:

runAfterBothAsync in interface CompletionStage<T>

applyToEither

<U> CompletionAwaitable<U> applyToEither(CompletionStage<? extends T> other,
 Function<? super T,U> fn)

Specified by:

applyToEither in interface CompletionStage<T>

applyToEitherAsync

<U> CompletionAwaitable<U> applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T,U> fn)

Specified by:

applyToEitherAsync in interface CompletionStage<T>

applyToEitherAsync

<U> CompletionAwaitable<U> applyToEitherAsync(CompletionStage<? extends T> other,
 Function<? super T,U> fn,
 Executor executor)

Specified by:

applyToEitherAsync in interface CompletionStage<T>

acceptEither

CompletionAwaitable<Void> acceptEither(CompletionStage<? extends T> other,
 Consumer<? super T> action)

Specified by:

acceptEither in interface CompletionStage<T>

acceptEitherAsync

CompletionAwaitable<Void> acceptEitherAsync(CompletionStage<? extends T> other,
 Consumer<? super T> action)

Specified by:

acceptEitherAsync in interface CompletionStage<T>

acceptEitherAsync

CompletionAwaitable<Void> acceptEitherAsync(CompletionStage<? extends T> other,
 Consumer<? super T> action,
 Executor executor)

Specified by:

acceptEitherAsync in interface CompletionStage<T>

runAfterEither

CompletionAwaitable<Void> runAfterEither(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterEither in interface CompletionStage<T>

runAfterEitherAsync

CompletionAwaitable<Void> runAfterEitherAsync(CompletionStage<?> other,
 Runnable action)

Specified by:

runAfterEitherAsync in interface CompletionStage<T>

runAfterEitherAsync

CompletionAwaitable<Void> runAfterEitherAsync(CompletionStage<?> other,
 Runnable action,
 Executor executor)

Specified by:

runAfterEitherAsync in interface CompletionStage<T>

thenCompose

<U> CompletionAwaitable<U> thenCompose(Function<? super T,? extends CompletionStage<U>> fn)

Specified by:

thenCompose in interface CompletionStage<T>

thenComposeAsync

<U> CompletionAwaitable<U> thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn)

Specified by:

thenComposeAsync in interface CompletionStage<T>

thenComposeAsync

<U> CompletionAwaitable<U> thenComposeAsync(Function<? super T,? extends CompletionStage<U>> fn,
 Executor executor)

Specified by:

thenComposeAsync in interface CompletionStage<T>

handle

<U> CompletionAwaitable<U> handle(BiFunction<? super T,Throwable,? extends U> fn)

Specified by:

handle in interface CompletionStage<T>

handleAsync

<U> CompletionAwaitable<U> handleAsync(BiFunction<? super T,Throwable,? extends U> fn)

Specified by:

handleAsync in interface CompletionStage<T>

handleAsync

<U> CompletionAwaitable<U> handleAsync(BiFunction<? super T,Throwable,? extends U> fn,
 Executor executor)

Specified by:

handleAsync in interface CompletionStage<T>

whenComplete

CompletionAwaitable<T> whenComplete(BiConsumer<? super T,? super Throwable> action)

Specified by:

whenComplete in interface CompletionStage<T>

whenCompleteAsync

CompletionAwaitable<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action)

Specified by:

whenCompleteAsync in interface CompletionStage<T>

whenCompleteAsync

CompletionAwaitable<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action,
 Executor executor)

Specified by:

whenCompleteAsync in interface CompletionStage<T>

exceptionally

CompletionAwaitable<T> exceptionally(Function<Throwable,? extends T> fn)

Specified by:

exceptionally in interface CompletionStage<T>

exceptionallyAccept

CompletionAwaitable<T> exceptionallyAccept(Consumer<Throwable> consumer)

Returns a new CompletionAwaitable that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied consumer. Otherwise, if this stage completes normally, then the returned stage also completes normally with the same value.

Parameters:

consumer - the consumer to invoke if this CompletionAwaitable completed exceptionally

Returns:

the new CompletionAwaitable