Hi Community,
I have a question on the JCSMP BlockingSynchronousSendGuaranteed.java sample:
What happens, if the broker doesn’t respond with either an ACK or a NACK?
Is this even possible or under which conditions could that occur?
(I read something about disk full could be one potential situation.)
Is there a timeout for how long the call will block?
In the comments I can see that PUB_ACK_TIME is set to 2000ms after which the API would retransmit a message. But does it ever timeout and return control to the application, if the broker isn’t responding with an ACK or a NACK?
// asynchronous send method and associated event callbacks. Calls to blockingSend() can
// block indefinitely waiting for receipt of an ACK or NACK for the message sent.
// If the API fails to receive either an ACK or NACK from the broker within the
// the JCSMPProperties.PUB_ACK_TIME timeout (default 2000ms) the API retransmits the
// message. The API will retransmit the message every JCSMPProperties.PUB_ACK_TIME milliseconds
// until an ACK or NACK is received. Typically the broker only fails to respond with an ACK
// or NACK if it is out of disk space to persist the received message.
//
// This method uses a CyclicBarrier to synchronize between sending the message and receiving
// either an ACK, in the ResponseReceivedEx callback, or a NACK, in the
// handleErrorEx callback.
public synchronized void blockingSend(XMLMessage message, Topic topic) throws Exception {
publishException = null;
CyclicBarrier barrier = new CyclicBarrier(2);
message.setCorrelationKey(barrier);
producer.send(message, topic);
try {
barrier.await();
} catch (InterruptedException e) {
throw(e);
} catch (BrokenBarrierException e) {
throw(e);
}
if (publishException != null) {
throw publishException;
}
}
// This is the blocking, synchronous send method implemented using the JCSMP API’s non-blocking,
This sounds like a potential rare edge case, but I’m curious what would happen in this situation.