Here you can find the source of within( CompletableFuture
| Parameter | Description |
|---|---|
| future | The completable future that must be completed within duration. |
| duration | The duration the future must be completed in. |
| T | The return type of the future. |
public static <T> CompletableFuture<T> within( CompletableFuture<T> future, Duration duration)
//package com.java2s;
//License from project: Apache License
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import java.time.Duration;
import java.util.concurrent.*;
import java.util.function.Function;
public class Main {
private static final ScheduledExecutorService scheduler = Executors
.newScheduledThreadPool(1, new ThreadFactoryBuilder()
.setDaemon(true).setNameFormat("failAfter-%d").build());
/** Takes a completable future, and ensures that it completes within a certain duration. If it does
* not, it is cancelled and completes exceptionally with TimeoutException.
* inspired by NoBlogDefFound: http://www.nurkiewicz.com/2014/12/asynchronous-timeouts-with.html
* @param future The completable future that must be completed within duration.
* @param duration The duration the future must be completed in.
* @param <T> The return type of the future.
* @return A completable future which completes with the original value if completed within
* duration, otherwise completes exceptionally with TimeoutException.
*///from w ww . j ava2 s . c o m
public static <T> CompletableFuture<T> within(
CompletableFuture<T> future, Duration duration) {
final CompletableFuture<T> timeout = failAfter(duration);
return future.applyToEither(timeout, Function.identity());
}
/** Generates a completable future which times out.
* inspired by NoBlogDefFound: http://www.nurkiewicz.com/2014/12/asynchronous-timeouts-with.html
* @param duration The duration to timeout after.
* @param <T> Ignored, since the future will always timeout.
* @return A completable future that will time out.
*/
public static <T> CompletableFuture<T> failAfter(Duration duration) {
final CompletableFuture<T> promise = new CompletableFuture<>();
scheduler.schedule(() -> {
final TimeoutException ex = new TimeoutException("Timeout after " + duration.toMillis() + " ms");
return promise.completeExceptionally(ex);
}, duration.toMillis(), TimeUnit.MILLISECONDS);
return promise;
}
}