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/*
* Copyright (c) 2024, 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.
*/
/*
* @test id=timeout
* @summary Stress test timed-Object.wait
* @run main TimedWaitALot 200
*/
/*
* @test id=timeout-notify
* @summary Test timed-Object.wait where the waiting thread is awakened with Object.notify
* at around the same time that the timeout expires.
* @run main TimedWaitALot 150 true false
*/
/*
* @test id=timeout-interrupt
* @summary Test timed-Object.wait where the waiting thread is awakened with Thread.interrupt
* at around the same time that the timeout expires.
* @run main TimedWaitALot 150 false true
*/
/*
* @test id=timeout-notify-interrupt
* @summary Test timed-Object.wait where the waiting thread is awakened with Object.notify
* and Thread.interrupt at around the same time that the timeout expires.
* @run main TimedWaitALot 100 true true
*/
import java.time.Instant;
import java.util.concurrent.Executors;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadLocalRandom;
public class TimedWaitALot {
public static void main(String[] args) throws Exception {
int iterations = Integer.parseInt(args[0]);
boolean notify = args.length >= 2 && "true".equals(args[1]);
boolean interrupt = args.length >=3 && "true".equals(args[2]);
// test all timeouts concurrently
int[] timeouts = { 10, 20, 50, 100 };
for (int i = 1; i <= iterations; i++) {
System.out.println(Instant.now() + " => " + i + " of " + iterations);
test(notify, interrupt, timeouts);
}
}
/**
* Start a first virtual thread to wait in Object.wait(millis).
* If {@code notify} is true, start a virtual thread to use Object.notifyAll at around
* the same time that the timeout expires.
* If {@code interrupt} is true, start virtual thread to interrupts the first virtual
* thread at around the same time as the timeout expires.
*/
static void test(boolean notify, boolean interrupt, int... timeouts) throws Exception {
try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
for (int timeout : timeouts) {
var queue = new SynchronousQueue<Thread>();
var lock = new Object();
// virtual thread waits with Object.wait(timeout)
executor.submit(() -> {
queue.put(Thread.currentThread());
synchronized (lock) {
lock.wait(timeout);
}
return null;
});
// wait for thread to start
Thread thread = queue.take();
// start thread to Object.notifyAll at around time that the timeout expires
if (notify) {
if (ThreadLocalRandom.current().nextBoolean()) {
synchronized (lock) {
sleepLessThan(timeout);
lock.notifyAll();
}
} else {
sleepLessThan(timeout);
synchronized (lock) {
lock.notifyAll();
}
}
}
// start thread to interrupt first thread at around time that the timeout expires
if (interrupt) {
executor.submit(() -> {
sleepLessThan(timeout);
thread.interrupt();
return null;
});
}
}
}
}
/**
* Sleeps for just less than the given timeout, in millis.
*/
private static void sleepLessThan(long timeout) throws InterruptedException {
int delta = ThreadLocalRandom.current().nextInt(10);
Thread.sleep(timeout - delta);
}
}
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