1 //******************************************************************************
2 //
3 // File: KillRegion.java
4 // Package: edu.rit.pj
5 // Unit: Class edu.rit.pj.ParallelTeam
6 //
7 // This Java source file is copyright (C) 2008 by Alan Kaminsky. All rights
8 // reserved. For further information, contact the author, Alan Kaminsky, at
9 // ark@cs.rit.edu.
10 //
11 // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12 // software; you can redistribute it and/or modify it under the terms of the GNU
13 // General Public License as published by the Free Software Foundation; either
14 // version 3 of the License, or (at your option) any later version.
15 //
16 // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17 // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18 // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 //
20 // Linking this library statically or dynamically with other modules is making a
21 // combined work based on this library. Thus, the terms and conditions of the GNU
22 // General Public License cover the whole combination.
23 //
24 // As a special exception, the copyright holders of this library give you
25 // permission to link this library with independent modules to produce an
26 // executable, regardless of the license terms of these independent modules, and
27 // to copy and distribute the resulting executable under terms of your choice,
28 // provided that you also meet, for each linked independent module, the terms
29 // and conditions of the license of that module. An independent module is a module
30 // which is not derived from or based on this library. If you modify this library,
31 // you may extend this exception to your version of the library, but you are not
32 // obligated to do so. If you do not wish to do so, delete this exception
33 // statement from your version.
34 //
35 // A copy of the GNU General Public License is provided in the file gpl.txt. You
36 // may also obtain a copy of the GNU General Public License on the World Wide
37 // Web at http://www.gnu.org/licenses/gpl.html.
38 //
39 //******************************************************************************
40
41 //******************************************************************************
42 // Additional file added 10/8/2014 by Jacob Litman to address the inability of
43 // the Java garbage collector to collect ParallelTeamThreads, whose run methods
44 // are infinite loops: since running threads are always GC roots, programs which
45 // set up many ParallelTeam objects will accumulate inactive threads and crash.
46 //
47 // Other modifications in ParallelTeam and ParallelTeamThread.
48 //******************************************************************************
49 package edu.rit.pj;
50
51 /**
52 * Provides a mechanism to shut down a ParallelTeam's threads, enabling garbage
53 * collection.
54 *
55 * @author Jacob Litman
56 */
57 public class KillRegion extends ParallelRegion {
58
59 /** {@inheritDoc} */
60 @Override
61 public void run() throws Exception {
62 // Empty run method.
63 ParallelTeamThread currentThread = getCurrentThread();
64 Thread thread = currentThread.getThread();
65 long totalThreads = ParallelTeamThread.totalThreads.getAndDecrement();
66 // System.out.printf(" Killing team %s thread %s of %d\n", currentThread.myTeam, thread, totalThreads);
67 }
68 }