Package play.libs.concurrent

Interface Futures

All Known Implementing Classes:

DefaultFutures

public interface Futures

Utilities for creating CompletionStage operations.

Method Summary

Modifier and Type	Method	Description
CompletionStage<Done>	delay(long amount, TimeUnit unit)	Creates a completion stage which is only completed after the delay.
CompletionStage<Done>	delay(Duration duration)	Creates a completion stage which is only completed after the delay.
<A> CompletionStage<A>	delayed(Callable<CompletionStage<A>> callable, long amount, TimeUnit unit)	Create a CompletionStage which, after a delay, will be redeemed with the result of a given callable.
<A> CompletionStage<A>	delayed(Callable<CompletionStage<A>> callable, Duration duration)	Create a CompletionStage which, after a delay, will be redeemed with the result of a given supplier.
static <A> CompletionStage<List<A>>	sequence(Iterable<? extends CompletionStage<A>> promises)	Combine the given CompletionStages into a single CompletionStage for the list of results.
static <A> CompletionStage<List<A>>	sequence(CompletionStage<A>... promises)	Combine the given CompletionStages into a single CompletionStage for the list of results.
<A> CompletionStage<A>	timeout(CompletionStage<A> stage, long amount, TimeUnit unit)	Creates a CompletionStage that returns either the input stage, or a timeout.
<A> CompletionStage<A>	timeout(CompletionStage<A> stage, Duration duration)	An alias for timeout that uses a Duration.

Method Detail

timeout

<A> CompletionStage<A> timeout(CompletionStage<A> stage,
                               long amount,
                               TimeUnit unit)

Creates a CompletionStage that returns either the input stage, or a timeout.

Note that timeout is not the same as cancellation. Even in case of timeout, the given completion stage will still complete, even though that completed value is not returned.

 CompletionStage<Double> callWithTimeout() {
     return futures.timeout(delayByOneSecond(), Duration.ofMillis(300));
 }
 

Type Parameters:

A - the completion's result type.

Parameters:

stage - the input completion stage that may time out.

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

unit - The time Unit.

Returns:

either the completed completion stage, or a completion stage that failed with timeout.

timeout

<A> CompletionStage<A> timeout(CompletionStage<A> stage,
                               Duration duration)

An alias for timeout that uses a Duration.

Type Parameters:

A - the completion stage that should be wrapped with a timeout.

Parameters:

stage - the input completion stage that may time out.

duration - The duration after which there is a timeout.

Returns:

the completion stage, or a completion stage that failed with timeout.

delayed

<A> CompletionStage<A> delayed(Callable<CompletionStage<A>> callable,
                               long amount,
                               TimeUnit unit)

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

Type Parameters:

A - the type of the completion's result.

Parameters:

callable - the input completion stage that is called after the delay.

amount - The time to wait.

unit - The units to use for the amount.

Returns:

the delayed CompletionStage wrapping supplier.

delay

CompletionStage<Done> delay(Duration duration)

Creates a completion stage which is only completed after the delay.

 Duration expected = Duration.ofSeconds(2);
 long start = System.currentTimeMillis();
 CompletionStage<Long> stage = futures.delay(expected).thenApply((v) -> {
     long end = System.currentTimeMillis();
     return (end - start);
 });
 

Parameters:

duration - the duration after which the completion stage is run.

Returns:

the completion stage.

delay

CompletionStage<Done> delay(long amount,
                            TimeUnit unit)

Creates a completion stage which is only completed after the delay.

Parameters:

amount - The time to wait.

unit - The units to use for the amount.

Returns:

the delayed CompletionStage.

delayed

<A> CompletionStage<A> delayed(Callable<CompletionStage<A>> callable,
                               Duration duration)

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

For example, to render a number indicating the delay, you can use the following method:

 private CompletionStage<Long> renderAfter(Duration duration) {
     long start = System.currentTimeMillis();
     return futures.delayed(() -> {
          long end = System.currentTimeMillis();
          return CompletableFuture.completedFuture(end - start);
     }, duration);
 }
 

Type Parameters:

A - the type of the completion's result.

Parameters:

callable - the input completion stage that is called after the delay.

duration - to wait.

Returns:

the delayed CompletionStage wrapping supplier.

sequence

static <A> CompletionStage<List<A>> sequence(Iterable<? extends 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

@SafeVarargs
static <A> CompletionStage<List<A>> sequence(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