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 and Jason Mehrens with assistance from

    30  * members of JCP JSR-166 Expert Group and released to the public

    31  * domain, as explained at

    32  * http://creativecommons.org/publicdomain/zero/1.0/

    33  */

    34 

    35 /*

    36  * @test

    37  * @summary Only one thread should be created when a thread needs to

    38  * be kept alive to service a delayed task waiting in the queue.

    39  * @library /lib/testlibrary/

    40  */

    41 

    42 import static java.util.concurrent.TimeUnit.MILLISECONDS;

    43 

    44 import java.util.concurrent.ScheduledThreadPoolExecutor;

    45 import java.util.concurrent.ThreadFactory;

    46 import java.util.concurrent.atomic.AtomicLong;

    47 import jdk.testlibrary.Utils;

    48 

    49 public class ThreadRestarts {

    50     static final long LONG_DELAY_MS = Utils.adjustTimeout(10_000);

    51     static final long FAR_FUTURE_MS = 10 * LONG_DELAY_MS;

    52 

    53     public static void main(String[] args) throws Exception {

    54         test(false);

    55         test(true);

    56     }

    57 

    58     private static void test(boolean allowTimeout) throws Exception {

    59         CountingThreadFactory ctf = new CountingThreadFactory();

    60         ScheduledThreadPoolExecutor stpe

    61             = new ScheduledThreadPoolExecutor(10, ctf);

    62         try {

    63             // schedule a dummy task in the "far future"

    64             Runnable nop = new Runnable() { public void run() {}};

    65             stpe.schedule(nop, FAR_FUTURE_MS, MILLISECONDS);

    66             stpe.setKeepAliveTime(1L, MILLISECONDS);

    67             stpe.allowCoreThreadTimeOut(allowTimeout);

    68             MILLISECONDS.sleep(12L);

    69         } finally {

    70             stpe.shutdownNow();

    71             if (!stpe.awaitTermination(LONG_DELAY_MS, MILLISECONDS))

    72                 throw new AssertionError("timed out");

    73         }

    74         if (ctf.count.get() > 1)

    75             throw new AssertionError(

    76                 String.format("%d threads created, 1 expected",

    77                               ctf.count.get()));

    78     }

    79 

    80     static class CountingThreadFactory implements ThreadFactory {

    81         final AtomicLong count = new AtomicLong(0L);

    82 

    83         public Thread newThread(Runnable r) {

    84             count.getAndIncrement();

    85             Thread t = new Thread(r);

    86             t.setDaemon(true);

    87             return t;

    88         }

    89     }

    90 }