/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.flink.runtime.util;
import org.junit.Test;
import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeoutException;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
public class AtomicDisposableReferenceCounterTest {
@Test
public void testSerialIncrementAndDecrement() {
AtomicDisposableReferenceCounter counter = new AtomicDisposableReferenceCounter();
assertTrue(counter.increment());
assertTrue(counter.decrement());
assertFalse(counter.increment());
assertFalse(counter.decrement());
}
@Test
public void testSerialIncrementAndDecrementWithCustomDisposeCount() {
AtomicDisposableReferenceCounter counter = new AtomicDisposableReferenceCounter(-2);
assertTrue(counter.increment());
assertFalse(counter.decrement());
assertFalse(counter.decrement());
assertTrue(counter.decrement());
}
@Test
public void testConcurrentIncrementAndDecrement() throws InterruptedException, ExecutionException, TimeoutException {
final Random random = new Random();
final ExecutorService executor = Executors.newFixedThreadPool(2);
try {
final MockIncrementer incrementer = new MockIncrementer();
final MockDecrementer decrementer = new MockDecrementer();
// Repeat this to provoke races
for (int i = 0; i < 256; i++) {
final AtomicDisposableReferenceCounter counter = new AtomicDisposableReferenceCounter();
incrementer.setCounter(counter);
decrementer.setCounter(counter);
counter.increment();
// Randomly decide which one should be first as the first task usually will win the race
boolean incrementFirst = random.nextBoolean();
Future<Boolean> success1 = executor.submit(incrementFirst ? incrementer : decrementer);
Future<Boolean> success2 = executor.submit(incrementFirst ? decrementer : incrementer);
// Only one of the two should win the race and return true
assertTrue(success1.get() ^ success2.get());
}
}
finally {
executor.shutdownNow();
}
}
private static class MockIncrementer implements Callable<Boolean> {
private AtomicDisposableReferenceCounter counter;
void setCounter(AtomicDisposableReferenceCounter counter) {
this.counter = counter;
}
@Override
public Boolean call() throws Exception {
return counter.increment();
}
}
private static class MockDecrementer implements Callable<Boolean> {
private AtomicDisposableReferenceCounter counter;
void setCounter(AtomicDisposableReferenceCounter counter) {
this.counter = counter;
}
@Override
public Boolean call() throws Exception {
return counter.decrement();
}
}
}