private static void testPromiseListenerAddWhenComplete(Throwable cause)
throws InterruptedException {
final CountDownLatch latch = new CountDownLatch(1);
final Promise<Void> promise = new DefaultPromise<Void>(ImmediateEventExecutor.INSTANCE);
promise.addListener(
new FutureListener<Void>() {
@Override
public void operationComplete(Future<Void> future) throws Exception {
promise.addListener(
new FutureListener<Void>() {
@Override
public void operationComplete(Future<Void> future) throws Exception {
latch.countDown();
}
});
}
});
if (cause == null) {
promise.setSuccess(null);
} else {
promise.setFailure(cause);
}
latch.await();
}
/**
* This test is mean to simulate the following sequence of events, which all take place on the I/O
* thread:
*
* <ol>
* <li>A write is done
* <li>The write operation completes, and the promise state is changed to done
* <li>A listener is added to the return from the write. The {@link
* FutureListener#operationComplete()} updates state which must be invoked before the
* response to the previous write is read.
* <li>The write operation
* </ol>
*/
private static void testLateListenerIsOrderedCorrectly(Throwable cause)
throws InterruptedException {
final EventExecutor executor = new TestEventExecutor();
try {
final AtomicInteger state = new AtomicInteger();
final CountDownLatch latch1 = new CountDownLatch(1);
final CountDownLatch latch2 = new CountDownLatch(2);
final Promise<Void> promise = new DefaultPromise<Void>(executor);
// Add a listener before completion so "lateListener" is used next time we add a listener.
promise.addListener(
new FutureListener<Void>() {
@Override
public void operationComplete(Future<Void> future) throws Exception {
assertTrue(state.compareAndSet(0, 1));
}
});
// Simulate write operation completing, which will execute listeners in another thread.
if (cause == null) {
promise.setSuccess(null);
} else {
promise.setFailure(cause);
}
// Add a "late listener"
promise.addListener(
new FutureListener<Void>() {
@Override
public void operationComplete(Future<Void> future) throws Exception {
assertTrue(state.compareAndSet(1, 2));
latch1.countDown();
}
});
// Wait for the listeners and late listeners to be completed.
latch1.await();
assertEquals(2, state.get());
// This is the important listener. A late listener that is added after all late listeners
// have completed, and needs to update state before a read operation (on the same executor).
executor.execute(
new Runnable() {
@Override
public void run() {
promise.addListener(
new FutureListener<Void>() {
@Override
public void operationComplete(Future<Void> future) throws Exception {
assertTrue(state.compareAndSet(2, 3));
latch2.countDown();
}
});
}
});
// Simulate a read operation being queued up in the executor.
executor.execute(
new Runnable() {
@Override
public void run() {
// This is the key, we depend upon the state being set in the next listener.
assertEquals(3, state.get());
latch2.countDown();
}
});
latch2.await();
} finally {
executor.shutdownGracefully(0, 0, TimeUnit.SECONDS).sync();
}
}