1 /*
2 * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @summary Stress parking with CompletableFuture timed get
27 * @requires vm.debug != true & vm.continuations
28 * @run main/othervm -Xmx1g CompletableFutureTimedGet 100000
29 */
30
31 import java.time.Duration;
32 import java.time.Instant;
33 import java.util.ArrayList;
34 import java.util.List;
35 import java.util.concurrent.CompletableFuture;
36 import java.util.concurrent.TimeUnit;
37 import java.util.concurrent.atomic.AtomicInteger;
38
39 public class CompletableFutureTimedGet {
40
41 static final String RESULT = "foo";
42
43 public static void main(String... args) throws InterruptedException {
44 int threadCount = 250_000;
45 if (args.length > 0) {
46 threadCount = Integer.parseInt(args[0]);
47 }
48
49 // the count of the number of threads that complete successfully
50 AtomicInteger completed = new AtomicInteger();
51
52 // list of futures and threads
53 List<CompletableFuture<String>> futures = new ArrayList<>();
54 List<Thread> threads = new ArrayList<>();
55
56 // start threads that wait with timeout for a result
57 for (int i = 0; i < threadCount; i++) {
58 var future = new CompletableFuture<String>();
59 futures.add(future);
60
61 // start a thread that uses a timed-get to wait for the result
62 Thread thread = Thread.ofVirtual().start(() -> {
63 try {
64 String result = future.get(1, TimeUnit.DAYS);
65 if (!RESULT.equals(result)) {
66 throw new RuntimeException("result=" + result);
67 }
68 completed.incrementAndGet();
69 } catch (Exception e) {
70 e.printStackTrace();
71 }
72 });
73 threads.add(thread);
74 }
75
76 // sets the result, which will unpark waiting threads
77 futures.forEach(f -> f.complete(RESULT));
78
79 // wait for all threads to terminate
80 long lastTimestamp = System.currentTimeMillis();
81 boolean done;
82 do {
83 done = true;
84 for (Thread t : threads) {
85 if (!t.join(Duration.ofSeconds(1))) {
86 done = false;
87 }
88 }
89
90 // print trace message so the output tracks progress
91 long currentTime = System.currentTimeMillis();
92 if (done || ((currentTime - lastTimestamp) > 500)) {
93 System.out.format("%s => completed %d of %d%n",
94 Instant.now(), completed.get(), threadCount);
95 lastTimestamp = currentTime;
96 }
97
98 } while (!done);
99
100 // all tasks should have completed successfully
101 int completedCount = completed.get();
102 if (completedCount != threadCount) {
103 throw new RuntimeException("completed = " + completedCount);
104 }
105 }
106 }