| /* |
| * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /** |
| * This test is useful for finding out whether a Thread can have a |
| * private variable indicate whether or not it is finished, and to illustrate |
| * the ease with which Threads terminate each other. |
| * |
| * @test |
| */ |
| |
| public class CancellableThreadTest { |
| public static final int THREADPAIRS = Integer.parseInt(System.getProperty("test.threadpairs", "128")); |
| |
| public static void main(String args[]) { |
| Thread[] threads = new Thread[THREADPAIRS]; |
| Canceller[] cancellers = new Canceller[THREADPAIRS]; |
| |
| System.out.println("Running with " + THREADPAIRS + " thread pairs"); |
| |
| for (int i = 0; i < THREADPAIRS; i++) { |
| cancellers[i] = new Canceller(i); |
| threads[i] = new Thread(cancellers[i]); |
| threads[i].start(); |
| } |
| |
| for (int i = 0; i < THREADPAIRS; i++) { |
| try { |
| threads[i].join(); |
| } catch (InterruptedException e) { |
| } |
| |
| if (cancellers[i].failed) { |
| throw new RuntimeException(" Test failed in " + i + " th pair. See error messages above."); |
| } |
| } |
| } |
| } |
| |
| class Canceller implements Runnable { |
| |
| private final CancellableTimer timer; |
| |
| public final String name; |
| public volatile boolean failed = false; |
| private volatile boolean hasBeenNotified = false; |
| |
| public Canceller(int index) { |
| this.name = "Canceller #" + index; |
| timer = new CancellableTimer(index, this); |
| } |
| |
| public void setHasBeenNotified() { |
| hasBeenNotified = true; |
| } |
| |
| /** |
| * This method contains the "action" of this Canceller Thread. |
| * It starts a CancellableTimer, waits, and then interrupts the |
| * CancellableTimer after the CancellableTimer notifies it. It then |
| * tries to join the CancellableTimer to itself and reports on whether |
| * it was successful in doing so. |
| */ |
| public void run() { |
| Thread timerThread = new Thread(timer); |
| |
| try { |
| synchronized(this) { |
| timerThread.start(); |
| wait(); |
| } |
| } catch (InterruptedException e) { |
| System.err.println(name + " was interrupted during wait()"); |
| failed = true; |
| } |
| |
| if (!hasBeenNotified) { |
| System.err.println(name + ".hasBeenNotified is not true as expected"); |
| failed = true; |
| } |
| |
| synchronized (timer) { |
| timerThread.interrupt(); |
| } |
| |
| try { |
| timerThread.join(); |
| } catch (InterruptedException ie) { |
| System.err.println(name + " was interrupted while joining " + |
| timer.name); |
| failed = true; |
| } |
| |
| if (timerThread.isAlive()) { |
| System.err.println(timer.name + " is still alive after " + name + |
| " attempted to join it."); |
| failed = true; |
| } |
| } |
| } |
| |
| /** |
| * This non-public class is the Thread which the Canceller Thread deliberately |
| * interrupts and then joins to itself after this Thread has slept for a few milliseconds. |
| */ |
| |
| class CancellableTimer implements Runnable { |
| |
| public final String name; |
| private final Canceller myCanceller; |
| |
| public CancellableTimer(int index, Canceller aCanceller) { |
| this.name = "CancellableTimer #" + index; |
| this.myCanceller = aCanceller; |
| } |
| |
| /** |
| * This is where this CancellableTimer does its work. It notifies its |
| * Canceller, waits for the Canceller to interrupt it, then catches the |
| * InterruptedException, and sleeps for a few milliseconds before exiting. |
| */ |
| public void run() { |
| try { |
| synchronized (this) { |
| synchronized (myCanceller) { |
| myCanceller.setHasBeenNotified(); |
| myCanceller.notify(); |
| } |
| wait(); |
| } |
| } catch (InterruptedException first) { |
| // isInterrupted should've been cleared here and we should not register a |
| // second interrupt |
| if (Thread.currentThread().isInterrupted()) { |
| System.err.println(name + " should not register an interrupt here"); |
| myCanceller.failed = true; |
| } |
| |
| try { |
| Thread.sleep(1); |
| } catch (InterruptedException e) { |
| System.err.println(name + " was interrupted when sleeping"); |
| myCanceller.failed = true; |
| } |
| } |
| } |
| } |