io.atlassian.util.concurrent

Class Promises

java.lang.Object

io.atlassian.util.concurrent.Promises

public final class Promises
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Promises.Callback<A> A callback that can be completed with a successful value or a failed exception.
static interface	Promises.SettablePromise<A> A promise that can be completed with a successful value or a failed exception.

Method Summary

Modifier and Type	Method and Description
static <A> Promise.TryConsumer<A>	compose(Consumer<? super A> success, Consumer<Throwable> failure) Create a Promise.TryConsumer by composing two Consumer.
static <A> Promise<A>	forCompletionStage(CompletionStage<A> stage) Create a promise from the input completion stage.
static <A> Promise<A>	forCompletionStage(CompletionStage<A> stage, Optional<Executor> executor) Create a promise from the input completion stage.
static <A> Promise<A>	forFuture(Future<A> future, Executor executor) Creates a promise from the given future.
static <A> Promise<A>	promise(A value) Creates a new, resolved promise for the specified concrete value.
static <A> Promise<A>	rejected(Throwable t) Creates a new, rejected promise from the given Throwable and result type.
static <A> Promises.SettablePromise<A>	settablePromise() Create a promise for the input effect.
static <A> Promises.SettablePromise<A>	settablePromise(Optional<Executor> executor)
static <B,A extends B> CompletableFuture<B>	toCompletableFuture(Promise<A> promise) Return a completable future based on the input promise
static <A> Function<A,Promise<A>>	toPromise() Deprecated. use promise(Object) as a method reference.
static <A> Promise<List<A>>	when(Iterable<? extends Promise<? extends A>> promises) Returns a new Promise representing the status of a list of other promises.
static <A> Promise<List<A>>	when(Promise<? extends A>... promises) Returns a new Promise representing the status of a list of other promises.
static <A> Promise<List<A>>	when(Stream<? extends Promise<? extends A>> promises) Returns a new Promise representing the status of a stream of other promises.

Methods inherited from class java.lang.Object

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

Method Detail

settablePromise

public static <A> Promises.SettablePromise<A> settablePromise()

Create a promise for the input effect.

Type Parameters:

A - type of the successful value.

Returns:

a new Promises.SettablePromise that can be fulfilled by calling the Promises.Callback methods it implements. Cancelling this Promise will have no consequence on the code that calls the callback.

settablePromise

public static <A> Promises.SettablePromise<A> settablePromise(@Nonnull
                                                              Optional<Executor> executor)

Type Parameters:

A - type of the successful value.

Parameters:

executor - to be called to run callbacks and transformations attached to the returned Promise. If None, they will be executed on the caller thread.

Returns:

a new Promises.SettablePromise that can be fulfilled by calling the Promises.Callback methods it implements. Cancelling this Promise will have no consequence on the code that calls the callback.

forCompletionStage

public static <A> Promise<A> forCompletionStage(@Nonnull
                                                CompletionStage<A> stage)

Create a promise from the input completion stage.

Type Parameters:

A - type of the successful value.

Parameters:

stage - a CompletionStage used as the precedent of the returned Promise.

Returns:

a new Promise that will be fulfilled with the same result that the CompletionStage has. If it implements CompletionStage.toCompletableFuture() then cancelling this Promise will cancel that CompletableFuture.

forCompletionStage

public static <A> Promise<A> forCompletionStage(@Nonnull
                                                CompletionStage<A> stage,
                                                @Nonnull
                                                Optional<Executor> executor)

Create a promise from the input completion stage.

Type Parameters:

A - type of the successful value.

Parameters:

stage - a CompletionStage used as the precedent of the returned Promise.

executor - to be called to run callbacks and transformations attached to the returned Promise. If None, they will be executed on the caller thread.

Returns:

a new Promise that will be fulfilled with the same result that the CompletionStage has. If it implements CompletionStage.toCompletableFuture() then cancelling this Promise will cancel that CompletableFuture.

toCompletableFuture

public static <B,A extends B> CompletableFuture<B> toCompletableFuture(@Nonnull
                                                                       Promise<A> promise)

Return a completable future based on the input promise

Type Parameters:

B - any super type of A that may be inferred.

Parameters:

promise - a Promise used as the precedent of the returned CompletableFuture.

Returns:

a new CompletableFuture that will be fulfilled with the same result that the Promise has.

when

@SafeVarargs
public static <A> Promise<List<A>> when(@Nonnull
                                                     Promise<? extends A>... promises)

Returns a new Promise representing the status of a list of other promises.

Type Parameters:

A - an A.

Parameters:

promises - The promises that the new promise should track

Returns:

The new, aggregate promise

when

public static <A> Promise<List<A>> when(@Nonnull
                                        Iterable<? extends Promise<? extends A>> promises)

Returns a new Promise representing the status of a list of other promises. More generally this is known as {code}sequence{code} as both List and Promise are traversable monads.

Type Parameters:

A - an A.

Parameters:

promises - The promises that the new promise should track

Returns:

The new, aggregate promise

when

public static <A> Promise<List<A>> when(@Nonnull
                                        Stream<? extends Promise<? extends A>> promises)

Returns a new Promise representing the status of a stream of other promises.

Type Parameters:

A - an A.

Parameters:

promises - The promises that the new promise should track

Returns:

The new, aggregate promise

toPromise

@Deprecated
public static <A> Function<A,Promise<A>> toPromise()

Deprecated. use promise(Object) as a method reference.

Creates a new, resolved promise for the specified concrete value.

Returns:

The new promise

Since:

2.7

promise

public static <A> Promise<A> promise(A value)

Creates a new, resolved promise for the specified concrete value.

Type Parameters:

A - an A.

Parameters:

value - The value for which a promise should be created

Returns:

The new promise

rejected

public static <A> Promise<A> rejected(@Nonnull
                                      Throwable t)

Creates a new, rejected promise from the given Throwable and result type.

Type Parameters:

A - an A.

Parameters:

t - The throwable

Returns:

The new promise

forFuture

public static <A> Promise<A> forFuture(@Nonnull
                                       Future<A> future,
                                       @Nonnull
                                       Executor executor)

Creates a promise from the given future.

Type Parameters:

A - possible future value type

Parameters:

future - The future delegate for the new promise

executor - an executor where a task will run that waits for the future to complete

Returns:

The new promise

compose

public static <A> Promise.TryConsumer<A> compose(@Nonnull
                                                 Consumer<? super A> success,
                                                 @Nonnull
                                                 Consumer<Throwable> failure)

Create a Promise.TryConsumer by composing two Consumer.

Type Parameters:

A - an A.

Parameters:

success - To run if the Future is successful

failure - To run if the Future fails

Returns:

The composed Callback