/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package tests.api.org.apache.harmony.kernel.dalvik;
import java.lang.reflect.Field;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.TimeUnit;
import junit.framework.Assert;
import junit.framework.TestCase;
import sun.misc.Unsafe;
/**
* Tests for the <code>park()</code> functionality of {@link Unsafe}.
*/
public class ThreadsTest extends TestCase {
private static Unsafe UNSAFE = null;
static {
/*
* Set up {@link #UNSAFE}. This subverts the access check to
* get the unique Unsafe instance. We can do this because
* there's no security manager installed when running the
* test.
*/
try {
Field field = Unsafe.class.getDeclaredField("THE_ONE");
field.setAccessible(true);
UNSAFE = (Unsafe) field.get(null);
} catch (NoSuchFieldException ex) {
throw new RuntimeException(ex);
} catch (IllegalAccessException ex) {
throw new RuntimeException(ex);
}
}
/** Test the case where the park times out. */
public void test_parkFor_1() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(2);
Parker parker = new Parker(barrier, false, 500);
Thread parkerThread = new Thread(parker);
Thread waiterThread =
new Thread(new WaitAndUnpark(barrier, 1000, parkerThread));
parkerThread.start();
waiterThread.start();
parker.assertDurationIsInRange(500);
waiterThread.join();
parkerThread.join();
}
/** Test the case where the unpark happens before the timeout. */
public void test_parkFor_2() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(2);
Parker parker = new Parker(barrier, false, 1000);
Thread parkerThread = new Thread(parker);
Thread waiterThread =
new Thread(new WaitAndUnpark(barrier, 300, parkerThread));
parkerThread.start();
waiterThread.start();
parker.assertDurationIsInRange(300);
waiterThread.join();
parkerThread.join();
}
/** Test the case where the thread is preemptively unparked. */
public void test_parkFor_3() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(1);
Parker parker = new Parker(barrier, false, 1000);
Thread parkerThread = new Thread(parker);
UNSAFE.unpark(parkerThread);
parkerThread.start();
parker.assertDurationIsInRange(0);
parkerThread.join();
}
/** Test the case where the park times out. */
public void test_parkUntil_1() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(2);
Parker parker = new Parker(barrier, true, 500);
Thread parkerThread = new Thread(parker);
Thread waiterThread =
new Thread(new WaitAndUnpark(barrier, 1000, parkerThread));
parkerThread.start();
waiterThread.start();
parker.assertDurationIsInRange(500);
waiterThread.join();
parkerThread.join();
}
/** Test the case where the unpark happens before the timeout. */
public void test_parkUntil_2() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(2);
Parker parker = new Parker(barrier, true, 1000);
Thread parkerThread = new Thread(parker);
Thread waiterThread =
new Thread(new WaitAndUnpark(barrier, 300, parkerThread));
parkerThread.start();
waiterThread.start();
parker.assertDurationIsInRange(300);
waiterThread.join();
parkerThread.join();
}
/** Test the case where the thread is preemptively unparked. */
public void test_parkUntil_3() throws Exception {
CyclicBarrier barrier = new CyclicBarrier(1);
Parker parker = new Parker(barrier, true, 1000);
Thread parkerThread = new Thread(parker);
UNSAFE.unpark(parkerThread);
parkerThread.start();
parker.assertDurationIsInRange(0);
parkerThread.join();
}
// TODO: Add more tests.
/**
* Helper <code>Runnable</code> for tests, which parks for or until
* the indicated value, noting the duration of time actually parked.
*/
private static class Parker implements Runnable {
private final CyclicBarrier barrier;
/** whether {@link #amount} is milliseconds to wait in an
* absolute fashion (<code>true</code>) or nanoseconds to wait
* in a relative fashion (<code>false</code>) */
private final boolean absolute;
/** amount to wait (see above) */
private final long amount;
/** whether the run has completed */
private boolean completed;
/** recorded start time */
private long startMillis;
/** recorded end time */
private long endMillis;
/**
* Construct an instance.
*
* @param absolute whether to use an absolute time or not; in
* either case, this constructor takes a duration to park for
* @param parkMillis the number of milliseconds to be parked
*/
public Parker(CyclicBarrier barrier, boolean absolute, long parkMillis) {
this.barrier = barrier;
this.absolute = absolute;
// Multiply by 1000000 because parkFor() takes nanoseconds.
this.amount = absolute ? parkMillis : parkMillis * 1000000;
}
public void run() {
try {
barrier.await(60, TimeUnit.SECONDS);
} catch (Exception e) {
throw new AssertionError(e);
}
boolean absolute = this.absolute;
long amount = this.amount;
long startNanos = System.nanoTime();
long start = System.currentTimeMillis();
if (absolute) {
UNSAFE.park(true, start + amount);
} else {
UNSAFE.park(false, amount);
}
long endNanos = System.nanoTime();
synchronized (this) {
startMillis = startNanos / 1000000;
endMillis = endNanos / 1000000;
completed = true;
notifyAll();
}
}
/**
* Wait for the test to complete and return the duration.
*
* @param maxWaitMillis the maximum amount of time to
* wait for the test to complete
* @return the duration in milliseconds
*/
public long getDurationMillis(long maxWaitMillis) {
synchronized (this) {
if (! completed) {
try {
wait(maxWaitMillis);
} catch (InterruptedException ignored) {
}
if (! completed) {
Assert.fail("parker hung for more than " + maxWaitMillis + " ms");
}
}
return endMillis - startMillis;
}
}
/**
* Asserts that the actual duration is within 10% of the
* given expected time.
*
* @param expectedMillis the expected duration, in milliseconds
*/
public void assertDurationIsInRange(long expectedMillis) {
/*
* Allow a bit more slop for the maximum on "expected
* instantaneous" results.
*/
long minimum = (long) ((double) expectedMillis * 0.80);
long maximum =
Math.max((long) ((double) expectedMillis * 1.20), 10);
long waitMillis = Math.max(expectedMillis * 10, 30);
long duration = getDurationMillis(waitMillis);
if (duration < minimum) {
Assert.fail("expected duration: " + expectedMillis +
" minimum duration: " + minimum +
" actual duration too short: " + duration);
} else if (duration > maximum) {
Assert.fail("expected duration: " + expectedMillis +
" maximum duration: " + maximum +
" actual duration too long: " + duration);
}
}
}
/**
* Helper <code>Runnable</code> for tests, which waits for the
* specified amount of time and then unparks an indicated thread.
*/
private static class WaitAndUnpark implements Runnable {
private final CyclicBarrier barrier;
private final long waitMillis;
private final Thread thread;
public WaitAndUnpark(CyclicBarrier barrier, long waitMillis, Thread thread) {
this.barrier = barrier;
this.waitMillis = waitMillis;
this.thread = thread;
}
public void run() {
try {
barrier.await(60, TimeUnit.SECONDS);
} catch (Exception e) {
throw new AssertionError(e);
}
try {
Thread.sleep(waitMillis);
} catch (InterruptedException ex) {
throw new RuntimeException("shouldn't happen", ex);
}
UNSAFE.unpark(thread);
}
}
}