| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // 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 com.google.devtools.build.lib.concurrent; |
| |
| import com.google.common.util.concurrent.FutureCallback; |
| import com.google.common.util.concurrent.Futures; |
| import com.google.common.util.concurrent.ListenableFuture; |
| |
| import java.util.List; |
| |
| import javax.annotation.Nullable; |
| |
| /** |
| * Utility class for working with futures. |
| */ |
| public class MoreFutures { |
| |
| private MoreFutures() {} |
| |
| /** |
| * Creates a new {@code ListenableFuture} whose value is a list containing the |
| * values of all its input futures, if all succeed. If any input fails, the |
| * returned future fails. If any of the futures fails, it cancels all the other futures. |
| * |
| * <p> This method is similar to {@code Futures.allAsList} but additionally it cancels all the |
| * futures in case any of them fails. |
| */ |
| public static <V> ListenableFuture<List<V>> allAsListOrCancelAll( |
| final Iterable<? extends ListenableFuture<? extends V>> futures) { |
| ListenableFuture<List<V>> combinedFuture = Futures.allAsList(futures); |
| Futures.addCallback(combinedFuture, new FutureCallback<List<V>>() { |
| @Override |
| public void onSuccess(@Nullable List<V> vs) {} |
| |
| /** |
| * In case of a failure of any of the futures (that gets propagated to combinedFuture) we |
| * cancel all the futures in the list. |
| */ |
| @Override |
| public void onFailure(Throwable ignore) { |
| for (ListenableFuture<? extends V> future : futures) { |
| future.cancel(true); |
| } |
| } |
| }); |
| return combinedFuture; |
| } |
| } |