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*
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* 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
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*
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import java.nio.ByteBuffer;
import java.util.List;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Flow.Subscription;
import java.util.concurrent.SubmissionPublisher;
import java.util.function.IntSupplier;
import java.util.stream.IntStream;
import java.net.http.HttpResponse.BodySubscriber;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import static java.lang.Long.MAX_VALUE;
import static java.lang.Long.MIN_VALUE;
import static java.lang.System.out;
import static java.nio.ByteBuffer.wrap;
import static java.util.concurrent.TimeUnit.SECONDS;
import static java.net.http.HttpResponse.BodySubscriber.buffering;
import static org.testng.Assert.*;
/*
* @test
* @summary Direct test for HttpResponse.BodySubscriber.buffering() cancellation
* @run testng/othervm BufferingSubscriberCancelTest
*/
public class BufferingSubscriberCancelTest {
@DataProvider(name = "bufferSizes")
public Object[][] bufferSizes() {
return new Object[][]{
// bufferSize should be irrelevant
{1}, {100}, {511}, {512}, {513}, {1024}, {2047}, {2048}
};
}
@Test(dataProvider = "bufferSizes")
public void cancelWithoutAnyItemsPublished(int bufferSize) throws Exception {
ExecutorService executor = Executors.newFixedThreadPool(1);
SubmissionPublisher<List<ByteBuffer>> publisher =
new SubmissionPublisher<>(executor, 1);
CountDownLatch gate = new CountDownLatch(1); // single onSubscribe
ExposingSubscriber exposingSubscriber = new ExposingSubscriber(gate);
BodySubscriber subscriber = buffering(exposingSubscriber, bufferSize);
publisher.subscribe(subscriber);
gate.await(30, SECONDS);
assertEqualsWithRetry(publisher::getNumberOfSubscribers, 1);
exposingSubscriber.subscription.cancel();
assertEqualsWithRetry(publisher::getNumberOfSubscribers, 0);
// further cancels/requests should be a no-op
Subscription s = exposingSubscriber.subscription;
s.cancel(); s.request(1);
s.cancel(); s.request(100); s.cancel();
s.cancel(); s.request(MAX_VALUE); s.cancel(); s.cancel();
s.cancel(); s.cancel(); s.cancel(); s.cancel();
s.request(MAX_VALUE); s.request(MAX_VALUE); s.request(MAX_VALUE);
s.request(-1); s.request(-100); s.request(MIN_VALUE);
assertEqualsWithRetry(publisher::getNumberOfSubscribers, 0);
executor.shutdown();
}
@DataProvider(name = "sizeAndItems")
public Object[][] sizeAndItems() {
return new Object[][] {
// bufferSize and item bytes must be equal to count onNext calls
// bufferSize items
{ 1, List.of(wrap(new byte[] { 1 })) },
{ 2, List.of(wrap(new byte[] { 1, 2 })) },
{ 3, List.of(wrap(new byte[] { 1, 2, 3})) },
{ 4, List.of(wrap(new byte[] { 1, 2 , 3, 4})) },
{ 5, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5})) },
{ 6, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5, 6})) },
{ 7, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5, 6, 7})) },
{ 8, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5, 6, 7, 8})) },
{ 9, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5, 6, 7, 8, 9})) },
{ 10, List.of(wrap(new byte[] { 1, 2 , 3, 4, 5, 6, 7, 8, 9, 10})) },
};
}
@Test(dataProvider = "sizeAndItems")
public void cancelWithItemsPublished(int bufferSize, List<ByteBuffer> items)
throws Exception
{
ExecutorService executor = Executors.newFixedThreadPool(1);
SubmissionPublisher<List<ByteBuffer>> publisher =
new SubmissionPublisher<>(executor, 24);
final int ITERATION_TIMES = 10;
// onSubscribe + onNext ITERATION_TIMES
CountDownLatch gate = new CountDownLatch(1 + ITERATION_TIMES);
ExposingSubscriber exposingSubscriber = new ExposingSubscriber(gate);
BodySubscriber subscriber = buffering(exposingSubscriber, bufferSize);
publisher.subscribe(subscriber);
assertEqualsWithRetry(publisher::getNumberOfSubscribers, 1);
IntStream.range(0, ITERATION_TIMES).forEach(x -> publisher.submit(items));
gate.await(30, SECONDS);
exposingSubscriber.subscription.cancel();
IntStream.range(0, ITERATION_TIMES+1).forEach(x -> publisher.submit(items));
assertEqualsWithRetry(publisher::getNumberOfSubscribers, 0);
assertEquals(exposingSubscriber.onNextInvocations, ITERATION_TIMES);
executor.shutdown();
}
// same as above but with more racy conditions, do not wait on the gate
@Test(dataProvider = "sizeAndItems")
public void cancelWithItemsPublishedNoWait(int bufferSize, List<ByteBuffer> items)
throws Exception
{
ExecutorService executor = Executors.newFixedThreadPool(1);
SubmissionPublisher<List<ByteBuffer>> publisher =
new SubmissionPublisher<>(executor, 24);
final int ITERATION_TIMES = 10;
// any callback will so, since onSub is guaranteed to be before onNext
CountDownLatch gate = new CountDownLatch(1);
ExposingSubscriber exposingSubscriber = new ExposingSubscriber(gate);
BodySubscriber subscriber = buffering(exposingSubscriber, bufferSize);
publisher.subscribe(subscriber);
IntStream.range(0, ITERATION_TIMES).forEach(x -> publisher.submit(items));
gate.await(30, SECONDS);
exposingSubscriber.subscription.cancel();
IntStream.range(0, ITERATION_TIMES+1).forEach(x -> publisher.submit(items));
int onNextInvocations = exposingSubscriber.onNextInvocations;
assertTrue(onNextInvocations <= ITERATION_TIMES,
"Expected <= " + ITERATION_TIMES + ", got " + onNextInvocations);
executor.shutdown();
}
static class ExposingSubscriber implements BodySubscriber<Void> {
final CountDownLatch gate;
volatile Subscription subscription;
volatile int onNextInvocations;
ExposingSubscriber(CountDownLatch gate) {
this.gate = gate;
}
@Override
public void onSubscribe(Subscription subscription) {
//out.println("onSubscribe " + subscription);
this.subscription = subscription;
gate.countDown();
subscription.request(MAX_VALUE); // forever
}
@Override
public void onNext(List<ByteBuffer> item) {
//out.println("onNext " + item);
onNextInvocations++;
gate.countDown();
}
@Override
public void onError(Throwable throwable) {
out.println("onError " + throwable);
}
@Override
public void onComplete() {
out.println("onComplete ");
}
@Override
public CompletionStage<Void> getBody() {
throw new UnsupportedOperationException("getBody is unsupported");
}
}
// There is a race between cancellation and subscriber callbacks, the
// following mechanism retries a number of times to allow for this race. The
// only requirement is that the expected result is actually observed.
static final int TEST_RECHECK_TIMES = 30;
static void assertEqualsWithRetry(IntSupplier actualSupplier, int expected)
throws Exception
{
int actual = expected + 1; // anything other than expected
for (int i=0; i< TEST_RECHECK_TIMES; i++) {
actual = actualSupplier.getAsInt();
if (actual == expected)
return;
Thread.sleep(100);
}
assertEquals(actual, expected); // will fail with the usual testng message
}
}