/*
* Copyright (C) 2011 The Guava Authors
*
* 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 com.google.common.collect;
import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.truth.Truth.assertThat;
import static java.lang.Long.MAX_VALUE;
import static java.lang.Thread.currentThread;
import static java.util.concurrent.Executors.newCachedThreadPool;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;
import com.google.common.base.Stopwatch;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
/**
* Tests for {@link Queues}.
*
* @author Dimitris Andreou
*/
public class QueuesTest extends TestCase {
/*
* All the following tests relate to BlockingQueue methods in Queues.
*/
public static List<BlockingQueue<Object>> blockingQueues() {
return ImmutableList.<BlockingQueue<Object>>of(
new LinkedBlockingQueue<Object>(),
new LinkedBlockingQueue<Object>(10),
new SynchronousQueue<Object>(),
new ArrayBlockingQueue<Object>(10),
new LinkedBlockingDeque<Object>(),
new LinkedBlockingDeque<Object>(10),
new PriorityBlockingQueue<Object>(10, Ordering.arbitrary()));
}
/*
* We need to perform operations in a thread pool, even for simple cases, because the queue might
* be a SynchronousQueue.
*/
private ExecutorService threadPool;
@Override
public void setUp() {
threadPool = newCachedThreadPool();
}
@Override
public void tearDown() throws InterruptedException {
threadPool.shutdown();
assertTrue("Some worker didn't finish in time", threadPool.awaitTermination(1, SECONDS));
}
private static <T> int drain(
BlockingQueue<T> q,
Collection<? super T> buffer,
int maxElements,
long timeout,
TimeUnit unit,
boolean interruptibly)
throws InterruptedException {
return interruptibly
? Queues.drain(q, buffer, maxElements, timeout, unit)
: Queues.drainUninterruptibly(q, buffer, maxElements, timeout, unit);
}
public void testMultipleProducers() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testMultipleProducers(q);
}
}
private void testMultipleProducers(BlockingQueue<Object> q) throws InterruptedException {
for (boolean interruptibly : new boolean[] {true, false}) {
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError = threadPool.submit(new Producer(q, 20));
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError1 = threadPool.submit(new Producer(q, 20));
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError2 = threadPool.submit(new Producer(q, 20));
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError3 = threadPool.submit(new Producer(q, 20));
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError4 = threadPool.submit(new Producer(q, 20));
List<Object> buf = newArrayList();
int elements = drain(q, buf, 100, MAX_VALUE, NANOSECONDS, interruptibly);
assertEquals(100, elements);
assertEquals(100, buf.size());
assertDrained(q);
}
}
public void testDrainTimesOut() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testDrainTimesOut(q);
}
}
private void testDrainTimesOut(BlockingQueue<Object> q) throws Exception {
for (boolean interruptibly : new boolean[] {true, false}) {
assertEquals(0, Queues.drain(q, ImmutableList.of(), 1, 10, MILLISECONDS));
Producer producer = new Producer(q, 1);
// producing one, will ask for two
Future<?> producerThread = threadPool.submit(producer);
producer.beganProducing.await();
// make sure we time out
Stopwatch timer = Stopwatch.createStarted();
int drained = drain(q, newArrayList(), 2, 10, MILLISECONDS, interruptibly);
assertThat(drained).isAtMost(1);
assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);
// If even the first one wasn't there, clean up so that the next test doesn't see an element.
producerThread.cancel(true);
producer.doneProducing.await();
if (drained == 0) {
q.poll(); // not necessarily there if producer was interrupted
}
}
}
public void testZeroElements() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testZeroElements(q);
}
}
private void testZeroElements(BlockingQueue<Object> q) throws InterruptedException {
for (boolean interruptibly : new boolean[] {true, false}) {
// asking to drain zero elements
assertEquals(0, drain(q, ImmutableList.of(), 0, 10, MILLISECONDS, interruptibly));
}
}
public void testEmpty() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testEmpty(q);
}
}
private void testEmpty(BlockingQueue<Object> q) {
assertDrained(q);
}
public void testNegativeMaxElements() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testNegativeMaxElements(q);
}
}
private void testNegativeMaxElements(BlockingQueue<Object> q) throws InterruptedException {
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError = threadPool.submit(new Producer(q, 1));
List<Object> buf = newArrayList();
int elements = Queues.drain(q, buf, -1, MAX_VALUE, NANOSECONDS);
assertEquals(elements, 0);
assertThat(buf).isEmpty();
// Free the producer thread, and give subsequent tests a clean slate.
q.take();
}
public void testDrain_throws() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testDrain_throws(q);
}
}
private void testDrain_throws(BlockingQueue<Object> q) {
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError = threadPool.submit(new Interrupter(currentThread()));
try {
Queues.drain(q, ImmutableList.of(), 100, MAX_VALUE, NANOSECONDS);
fail();
} catch (InterruptedException expected) {
}
}
public void testDrainUninterruptibly_doesNotThrow() throws Exception {
for (BlockingQueue<Object> q : blockingQueues()) {
testDrainUninterruptibly_doesNotThrow(q);
}
}
private void testDrainUninterruptibly_doesNotThrow(final BlockingQueue<Object> q) {
final Thread mainThread = currentThread();
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError =
threadPool.submit(
new Callable<Void>() {
public Void call() throws InterruptedException {
new Producer(q, 50).call();
new Interrupter(mainThread).run();
new Producer(q, 50).call();
return null;
}
});
List<Object> buf = newArrayList();
int elements = Queues.drainUninterruptibly(q, buf, 100, MAX_VALUE, NANOSECONDS);
// so when this drains all elements, we know the thread has also been interrupted in between
assertTrue(Thread.interrupted());
assertEquals(100, elements);
assertEquals(100, buf.size());
}
public void testNewLinkedBlockingDequeCapacity() {
try {
Queues.newLinkedBlockingDeque(0);
fail("Should have thrown IllegalArgumentException");
} catch (IllegalArgumentException expected) {
// any capacity less than 1 should throw IllegalArgumentException
}
assertEquals(1, Queues.newLinkedBlockingDeque(1).remainingCapacity());
assertEquals(11, Queues.newLinkedBlockingDeque(11).remainingCapacity());
}
public void testNewLinkedBlockingQueueCapacity() {
try {
Queues.newLinkedBlockingQueue(0);
fail("Should have thrown IllegalArgumentException");
} catch (IllegalArgumentException expected) {
// any capacity less than 1 should throw IllegalArgumentException
}
assertEquals(1, Queues.newLinkedBlockingQueue(1).remainingCapacity());
assertEquals(11, Queues.newLinkedBlockingQueue(11).remainingCapacity());
}
/** Checks that #drain() invocations behave correctly for a drained (empty) queue. */
private void assertDrained(BlockingQueue<Object> q) {
assertNull(q.peek());
assertInterruptibleDrained(q);
assertUninterruptibleDrained(q);
}
private void assertInterruptibleDrained(BlockingQueue<Object> q) {
// nothing to drain, thus this should wait doing nothing
try {
assertEquals(0, Queues.drain(q, ImmutableList.of(), 0, 10, MILLISECONDS));
} catch (InterruptedException e) {
throw new AssertionError();
}
// but does the wait actually occurs?
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError = threadPool.submit(new Interrupter(currentThread()));
try {
// if waiting works, this should get stuck
Queues.drain(q, newArrayList(), 1, MAX_VALUE, NANOSECONDS);
fail();
} catch (InterruptedException expected) {
// we indeed waited; a slow thread had enough time to interrupt us
}
}
// same as above; uninterruptible version
private void assertUninterruptibleDrained(BlockingQueue<Object> q) {
assertEquals(0, Queues.drainUninterruptibly(q, ImmutableList.of(), 0, 10, MILLISECONDS));
// but does the wait actually occurs?
@SuppressWarnings("unused") // go/futurereturn-lsc
Future<?> possiblyIgnoredError = threadPool.submit(new Interrupter(currentThread()));
Stopwatch timer = Stopwatch.createStarted();
Queues.drainUninterruptibly(q, newArrayList(), 1, 10, MILLISECONDS);
assertThat(timer.elapsed(MILLISECONDS)).isAtLeast(10L);
// wait for interrupted status and clear it
while (!Thread.interrupted()) {
Thread.yield();
}
}
private static class Producer implements Callable<Void> {
final BlockingQueue<Object> q;
final int elements;
final CountDownLatch beganProducing = new CountDownLatch(1);
final CountDownLatch doneProducing = new CountDownLatch(1);
Producer(BlockingQueue<Object> q, int elements) {
this.q = q;
this.elements = elements;
}
@Override
public Void call() throws InterruptedException {
try {
beganProducing.countDown();
for (int i = 0; i < elements; i++) {
q.put(new Object());
}
return null;
} finally {
doneProducing.countDown();
}
}
}
private static class Interrupter implements Runnable {
final Thread threadToInterrupt;
Interrupter(Thread threadToInterrupt) {
this.threadToInterrupt = threadToInterrupt;
}
@Override
public void run() {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
throw new AssertionError();
} finally {
threadToInterrupt.interrupt();
}
}
}
}