play.libs.concurrent

Class Futures

java.lang.Object

play.libs.concurrent.Futures

public class Futures
extends java.lang.Object

Utilities for creating CompletionStage.

Constructor Summary

Constructors

Constructor and Description
Futures()

Method Summary

Modifier and Type	Method and Description
static <A> java.util.concurrent.CompletionStage<A>	delayed(java.util.function.Supplier<A> supplier, long delay, java.util.concurrent.TimeUnit unit, java.util.concurrent.Executor executor) Create a CompletionStage which, after a delay, will be redeemed with the result of a given supplier.
static <A> java.util.concurrent.CompletionStage<java.util.List<A>>	sequence(java.util.concurrent.CompletionStage<A>... promises) Combine the given CompletionStages into a single CompletionStage for the list of results.
static <A> java.util.concurrent.CompletionStage<java.util.List<A>>	sequence(java.lang.Iterable<? extends java.util.concurrent.CompletionStage<A>> promises) Combine the given CompletionStages into a single CompletionStage for the list of results.
static <A> java.util.concurrent.CompletionStage<A>	timeout(A value, long delay, java.util.concurrent.TimeUnit unit) Create a CompletionStage that is redeemed after a timeout.
static <A> java.util.concurrent.CompletionStage<A>	timeout(long delay, java.util.concurrent.TimeUnit unit) Creates a CompletionStage timer that throws a PromiseTimeoutException after a given timeout.

Methods inherited from class java.lang.Object

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

Constructor Detail

Futures

public Futures()

Method Detail

sequence

public static <A> java.util.concurrent.CompletionStage<java.util.List<A>> sequence(java.lang.Iterable<? extends java.util.concurrent.CompletionStage<A>> promises)

Combine the given CompletionStages into a single CompletionStage for the list of results. The sequencing operations are performed in the default ExecutionContext.

Type Parameters:

A - the type of the completion's result.

Parameters:

promises - The CompletionStages to combine

Returns:

A single CompletionStage whose methods act on the list of redeemed CompletionStages

sequence

public static <A> java.util.concurrent.CompletionStage<java.util.List<A>> sequence(java.util.concurrent.CompletionStage<A>... promises)

Combine the given CompletionStages into a single CompletionStage for the list of results. The sequencing operations are performed in the default ExecutionContext.

Type Parameters:

A - the type of the completion's result.

Parameters:

promises - The CompletionStages to combine

Returns:

A single CompletionStage whose methods act on the list of redeemed CompletionStage

timeout

public static <A> java.util.concurrent.CompletionStage<A> timeout(A value,
                                                                  long delay,
                                                                  java.util.concurrent.TimeUnit unit)

Create a CompletionStage that is redeemed after a timeout. This method is useful for returning fallback values on timeout. The underlying implementation uses TimerTask, which has a resolution in milliseconds.

Type Parameters:

A - the type of the completion's result.

Parameters:

value - The result value to use to complete the CompletionStage.

delay - The delay (expressed with the corresponding unit).

unit - The time unit, i.e. java.util.concurrent.TimeUnit.MILLISECONDS

Returns:

the CompletionStage wrapping the result value

timeout

public static <A> java.util.concurrent.CompletionStage<A> timeout(long delay,
                                                                  java.util.concurrent.TimeUnit unit)

Creates a CompletionStage timer that throws a PromiseTimeoutException after a given timeout. The returned CompletionStage is usually combined with other CompletionStage, i.e. completionStage.applyToEither(timeout, Function.identity()) The underlying implementation uses TimerTask, which has a resolution in milliseconds. A previous implementation used CompletionStage<Void> which made it unsuitable for composition. Cast with Futures.<Void>timeout if necessary.

Type Parameters:

A - the type of the completion's result.

Parameters:

delay - The delay (expressed with the corresponding unit).

unit - The time Unit.

Returns:

a CompletionStage that failed exceptionally

delayed

public static <A> java.util.concurrent.CompletionStage<A> delayed(java.util.function.Supplier<A> supplier,
                                                                  long delay,
                                                                  java.util.concurrent.TimeUnit unit,
                                                                  java.util.concurrent.Executor executor)

Create a CompletionStage which, after a delay, will be redeemed with the result of a given supplier. The supplier will be called after the delay.

Type Parameters:

A - the type of the completion's result.

Parameters:

supplier - The supplier to call to fulfill the CompletionStage.

delay - The time to wait.

unit - The units to use for the delay.

executor - The executor to run the supplier in.

Returns:

the delayed CompletionStage wrapping supplier.