/*
* 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
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*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* @test
* @bug 4486658
* @compile -source 1.5 CancelledFutureLoops.java
* @run main/timeout=2000 CancelledFutureLoops
* @summary Checks for responsiveness of futures to cancellation.
* Runs under the assumption that ITERS computations require more than
* TIMEOUT msecs to complete.
*/
import java.util.concurrent.*;
import java.util.concurrent.locks.*;
import java.util.*;
public final class CancelledFutureLoops {
static final ExecutorService pool = Executors.newCachedThreadPool();
static final LoopHelpers.SimpleRandom rng = new LoopHelpers.SimpleRandom();
static boolean print = false;
static final int ITERS = 1000000;
static final long TIMEOUT = 100;
public static void main(String[] args) throws Exception {
int maxThreads = 5;
if (args.length > 0)
maxThreads = Integer.parseInt(args[0]);
print = true;
for (int i = 2; i <= maxThreads; i += (i+1) >>> 1) {
System.out.print("Threads: " + i);
try {
new FutureLoop(i).test();
}
catch (BrokenBarrierException bb) {
// OK; ignore
}
catch (ExecutionException ee) {
// OK; ignore
}
Thread.sleep(TIMEOUT);
}
pool.shutdown();
if (! pool.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS))
throw new Error();
}
static final class FutureLoop implements Callable {
private int v = rng.next();
private final ReentrantLock lock = new ReentrantLock();
private final LoopHelpers.BarrierTimer timer = new LoopHelpers.BarrierTimer();
private final CyclicBarrier barrier;
private final int nthreads;
FutureLoop(int nthreads) {
this.nthreads = nthreads;
barrier = new CyclicBarrier(nthreads+1, timer);
}
final void test() throws Exception {
Future[] futures = new Future[nthreads];
for (int i = 0; i < nthreads; ++i)
futures[i] = pool.submit(this);
barrier.await();
Thread.sleep(TIMEOUT);
boolean tooLate = false;
for (int i = 1; i < nthreads; ++i) {
if (!futures[i].cancel(true))
tooLate = true;
// Unbunch some of the cancels
if ( (i & 3) == 0)
Thread.sleep(1 + rng.next() % 10);
}
Object f0 = futures[0].get();
if (!tooLate) {
for (int i = 1; i < nthreads; ++i) {
if (!futures[i].isDone() || !futures[i].isCancelled())
throw new Error("Only one thread should complete");
}
}
else
System.out.print("(cancelled too late) ");
long endTime = System.nanoTime();
long time = endTime - timer.startTime;
if (print) {
double secs = (double)(time) / 1000000000.0;
System.out.println("\t " + secs + "s run time");
}
}
public final Object call() throws Exception {
barrier.await();
int sum = v;
int x = 0;
int n = ITERS;
while (n-- > 0) {
lock.lockInterruptibly();
try {
v = x = LoopHelpers.compute1(v);
}
finally {
lock.unlock();
}
sum += LoopHelpers.compute2(LoopHelpers.compute2(x));
}
return new Integer(sum);
}
}
}