1 /*
   2  * Copyright (c) 2007, 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  * @bug 6571733 6460501
  27  * @summary Check that regaining a read lock succeeds after a write
  28  *          lock attempt times out
  29  */
  30 import java.util.concurrent.locks.*;
  31 import java.util.concurrent.*;
  32 
  33 public class Bug6571733 {
  34 
  35     void test(String[] args) throws Throwable {
  36         test(true);
  37         test(false);
  38     }
  39 
  40     void test(boolean fairness) throws Throwable {
  41         final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(fairness);
  42 
  43         // obtain read lock
  44         lock.readLock().lock();
  45 
  46         Thread thread = new Thread() { public void run() {
  47             try {
  48                 check (! lock.writeLock().tryLock(0, TimeUnit.DAYS));
  49 
  50                 lock.readLock().lock();
  51                 lock.readLock().unlock();
  52             } catch (Throwable t) { unexpected(t); }}};
  53 
  54         thread.start();
  55         thread.join();
  56     }
  57 
  58     //--------------------- Infrastructure ---------------------------
  59     volatile int passed = 0, failed = 0;
  60     void pass() {passed++;}
  61     void fail() {failed++; Thread.dumpStack();}
  62     void fail(String msg) {System.err.println(msg); fail();}
  63     void unexpected(Throwable t) {failed++; t.printStackTrace();}
  64     void check(boolean cond) {if (cond) pass(); else fail();}
  65     public static void main(String[] args) throws Throwable {
  66         new Bug6571733().instanceMain(args);}
  67     void instanceMain(String[] args) throws Throwable {
  68         try {test(args);} catch (Throwable t) {unexpected(t);}
  69         System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
  70         if (failed > 0) throw new AssertionError("Some tests failed");}
  71 }