/**
* Copyright 2011-2015 John Ericksen
*
* 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 org.androidtransfuse.event;
import org.androidtransfuse.annotations.Observes;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
/**
* Test cases highlighting concurrency when registering, unregistering and triggering on events.
*
* @author John Ericksen
*/
public class UnregisterConcurrencyTest {
private static final String EVENT = "event";
private static final int INPUT_COUNT = 100;
private static final int WAIT_PERIOD = 1000;
private EventManager eventManager;
private ExecutorService executorService;
public abstract class RegisterableBase {
private boolean registered = false;
private boolean unregistered = false;
public synchronized void register() {
registered = true;
eventManager.register(String.class, getEventObserver());
}
public synchronized void unregister() {
if (registered) {
eventManager.unregister(getEventObserver());
unregistered = true;
}
}
public boolean isUnregistered() {
return unregistered;
}
public abstract EventObserver<String> getEventObserver();
}
public class DeadlockTrigger extends RegisterableBase {
private int count = 0;
private EventObserver<String> eventObserver = new EventObserver<String>() {
@Override
public void trigger(String event) {
deadlock(event);
}
};
@Observes
public void deadlock(String event) {
if (count < 2) {
sleep();
eventManager.trigger(event);
}
count++;
}
@Override
public EventObserver<String> getEventObserver() {
return eventObserver;
}
}
public class EventWatcher extends RegisterableBase {
private boolean calledAfterUnregister = false;
private EventObserver<String> eventObserver = new EventObserver<String>() {
@Override
public void trigger(String event) {
event(event);
}
};
public void event(@Observes String event) {
sleep();
calledAfterUnregister = isUnregistered();
}
public boolean isCalledAfterUnregister() {
return calledAfterUnregister;
}
@Override
public EventObserver<String> getEventObserver() {
return eventObserver;
}
}
public class EventRegistration implements Runnable {
private RegisterableBase watcher;
public EventRegistration(RegisterableBase watcher) {
this.watcher = watcher;
}
@Override
public void run() {
watcher.register();
}
}
public class EventUnregistration implements Runnable {
private RegisterableBase watcher;
public EventUnregistration(RegisterableBase watcher) {
this.watcher = watcher;
}
@Override
public void run() {
watcher.unregister();
}
}
public class EventTrigger implements Runnable {
@Override
public void run() {
eventManager.trigger(EVENT);
}
}
@Before
public void setup() {
eventManager = new EventManager();
executorService = Executors.newFixedThreadPool(4);
}
@Test
@Ignore
public void hammerLifecycleTest() throws InterruptedException {
List<EventWatcher> registrations = new ArrayList<EventWatcher>();
for (int i = 0; i < INPUT_COUNT; i++) {
EventWatcher eventWatcher = new EventWatcher();
registrations.add(eventWatcher);
executorService.execute(new EventRegistration(eventWatcher));
executorService.execute(new EventUnregistration(eventWatcher));
executorService.execute(new EventTrigger());
}
executorService.shutdown();
executorService.awaitTermination(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
for (EventWatcher registration : registrations) {
assertFalse(registration.isCalledAfterUnregister());
}
}
/**
* Exercises possible deadlock conditions where an event triggers itself, both during registration and during
* event posting.
*
* @throws InterruptedException
*/
@Test
public void deadlockTest() throws InterruptedException {
for (int i = 0; i < INPUT_COUNT; i++) {
final DeadlockTrigger deadlockTrigger = new DeadlockTrigger();
executorService.execute(new EventRegistration(deadlockTrigger));
executorService.execute(new EventUnregistration(deadlockTrigger));
executorService.execute(new EventTrigger());
}
// Wait 100ms for threads to finish. If not finished, assume deadlock.
executorService.shutdown();
assertTrue(executorService.awaitTermination(WAIT_PERIOD, TimeUnit.MILLISECONDS));
}
public class DeadlockPair extends RegisterableBase {
private DeadlockPair deadlockPair = null;
private EventObserver<String> eventObserver = new EventObserver<String>() {
@Override
public void trigger(String event) {
deadlockPair.event(event);
}
};
@Observes
public void event(String event) {
if (deadlockPair != null) {
sleep();
deadlockPair.unregister();
}
}
public void setDeadlockPair(DeadlockPair deadlockPair) {
this.deadlockPair = deadlockPair;
}
@Override
public EventObserver<String> getEventObserver() {
return eventObserver;
}
}
@Test
@Ignore
public void deadlockPairTest() throws InterruptedException {
for (int i = 0; i < INPUT_COUNT; i++) {
DeadlockPair pair1 = new DeadlockPair();
DeadlockPair pair2 = new DeadlockPair();
pair1.setDeadlockPair(pair2);
pair2.setDeadlockPair(pair1);
executorService.execute(new EventRegistration(pair1));
executorService.execute(new EventTrigger());
}
// Wait 100ms for threads to finish. If not finished, assume deadlock.
executorService.shutdown();
assertTrue(executorService.awaitTermination(WAIT_PERIOD, TimeUnit.MILLISECONDS));
}
private static void sleep() {
// Adding some time to allow unregisters to happen often.
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}