1 /*
   2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  */
  22 
  23 /*
  24  * This file is available under and governed by the GNU General Public
  25  * License version 2 only, as published by the Free Software Foundation.
  26  * However, the following notice accompanied the original version of this
  27  * file:
  28  *
  29  * Written by Martin Buchholz with assistance from members of JCP
  30  * JSR-166 Expert Group and released to the public domain, as
  31  * explained at http://creativecommons.org/publicdomain/zero/1.0/
  32  */
  33 
  34 /*
  35  * @test
  36  * @bug 8073704
  37  * @summary Checks that once isDone() returns true,
  38  * get() never throws InterruptedException or TimeoutException
  39  * @library /test/lib
  40  */
  41 
  42 import static java.util.concurrent.TimeUnit.MILLISECONDS;
  43 
  44 import java.util.ArrayList;
  45 import java.util.concurrent.Callable;
  46 import java.util.concurrent.CountDownLatch;
  47 import java.util.concurrent.ExecutorService;
  48 import java.util.concurrent.Executors;
  49 import java.util.concurrent.Future;
  50 import java.util.concurrent.FutureTask;
  51 import java.util.concurrent.ThreadLocalRandom;
  52 import java.util.concurrent.TimeUnit;
  53 import java.util.concurrent.atomic.AtomicBoolean;
  54 import java.util.concurrent.atomic.AtomicReference;
  55 import jdk.test.lib.Utils;
  56 
  57 public class DoneMeansDone {
  58     static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000);
  59 
  60     public static void main(String[] args) throws Throwable {
  61         final int iters = 1000;
  62         final int nThreads = 2;
  63         final AtomicBoolean done = new AtomicBoolean(false);
  64         final AtomicReference<FutureTask<Boolean>> a = new AtomicReference<>();
  65         final CountDownLatch threadsStarted = new CountDownLatch(nThreads);
  66         final Callable<Boolean> alwaysTrue = new Callable<>() {
  67             public Boolean call() {
  68                 return true;
  69             }};
  70 
  71         final Runnable observer = new Runnable() { public void run() {
  72             threadsStarted.countDown();
  73             final ThreadLocalRandom rnd = ThreadLocalRandom.current();
  74             try {
  75                 for (FutureTask<Boolean> f; !done.get();) {
  76                     f = a.get();
  77                     if (f != null) {
  78                         do {} while (!f.isDone());
  79                         Thread.currentThread().interrupt();
  80                         if (!(rnd.nextBoolean()
  81                               ? f.get()
  82                               : f.get(-1L, TimeUnit.DAYS)))
  83                             throw new AssertionError();
  84                     }
  85                 }
  86             } catch (Exception t) { throw new AssertionError(t); }
  87         }};
  88 
  89         final ArrayList<Future<?>> futures = new ArrayList<>(nThreads);
  90         final ExecutorService pool = Executors.newCachedThreadPool();
  91         for (int i = 0; i < nThreads; i++)
  92             futures.add(pool.submit(observer));
  93         threadsStarted.await();
  94         for (int i = 0; i < iters; i++) {
  95             FutureTask<Boolean> f = new FutureTask<>(alwaysTrue);
  96             a.set(f);
  97             f.run();
  98         }
  99         done.set(true);
 100         pool.shutdown();
 101         if (!pool.awaitTermination(LONG_DELAY_MS, MILLISECONDS))
 102             throw new AssertionError();
 103         for (Future<?> future : futures)
 104             future.get();
 105     }
 106 }