io.stargate.sgv2.api.common.futures.Futures Maven / Gradle / Ivy
/*
* Copyright The Stargate Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.stargate.sgv2.api.common.futures;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;
public class Futures {
/**
* Gets a future without reacting to interruptions: if the current thread is interrupted, the
* operation continues until the future completes, and the thread will be re-interrupted upon
* completion.
*
* If the future fails with an unchecked exception, it will be rethrown as-is. If it fails with
* a checked exception, it will be wrapped in an {@link UncheckedExecutionException}.
*/
public static T getUninterruptibly(CompletionStage stage) {
boolean interrupted = false;
try {
while (true) {
try {
return stage.toCompletableFuture().get();
} catch (InterruptedException e) {
interrupted = true;
} catch (ExecutionException e) {
Throwable cause = e.getCause();
if (cause instanceof RuntimeException) {
throw ((RuntimeException) cause);
} else if (cause instanceof Error) {
throw ((Error) cause);
} else {
throw new UncheckedExecutionException(cause);
}
}
}
} finally {
if (interrupted) {
Thread.currentThread().interrupt();
}
}
}
public static CompletableFuture failedFuture(Exception e) {
CompletableFuture f = new CompletableFuture<>();
f.completeExceptionally(e);
return f;
}
/** Returns a future of all the results, or a failed future if any of the inputs fails. */
public static CompletionStage> sequence(List> futures) {
return CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
.thenApply(
v ->
futures.stream()
.map(f -> f.toCompletableFuture().join())
.collect(Collectors.toList()));
}
}