1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
// 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 static com.google.common.util.concurrent.Futures.addCallback;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import com.google.common.collect.Iterables;
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 java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import javax.annotation.Nullable;
/**
* Utility class for working with futures.
*/
public class MoreFutures {
private MoreFutures() {}
/**
* Waits for the first one of the following to occur:
* <ul>
* <li>All of the given futures complete successfully.
* <li>One of the given futures has an {@link ExecutionException}. This {@link ExecutionException}
* is propagated. (N.B. If multiple futures have {@link ExecutionExceptions}s, one will be
* selected non-deterministically.)
* <li>The calling thread is interrupted. The {@link InterruptedException} is propagated.
* </ul>
*/
public static <V> void waitForAllInterruptiblyFailFast(
Iterable<? extends Future<? extends V>> futures)
throws ExecutionException, InterruptedException {
int numFutures = Iterables.size(futures);
while (true) {
int numCompletedFutures = 0;
for (Future<? extends V> future : futures) {
try {
future.get(1, TimeUnit.MILLISECONDS);
} catch (TimeoutException te) {
continue;
} catch (ExecutionException ee) {
throw ee;
}
numCompletedFutures++;
}
if (numCompletedFutures == numFutures) {
return;
}
}
}
/**
* 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);
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);
}
}
},
directExecutor());
return combinedFuture;
}
}
|
