问题
I'm implementing an Domain Event infrastructure, but the project doesn't allow any messaging infra(financial services client) so found an alternative in Hazelcast Topics and ExecutorService,
But the problem is when running in cluster the message shall be delivered to listeners which is going to be running in cluster, so for a cluster of 2, we have same listener running in 2 jvm, and message consume twice and acted upon, suppose the Domain event is supposed to perform some non idempotent operation like credit some loyalty points, unless I explicitly maintain a trace of domain event acted upon and check against that everytime I receive an event, I will end up crediting it twice, "any suggestion implementing this without having to write those boiler plates possibly at the infralayer", or is there a known patter for such implementation.
Edit: Meanwhile I'm also evaluating Hazelcast ExecutorService as suggested Here
回答1:
The use case you described can be solved by using Hazelcast's Queues instead of Topics. The main reason to use topics is if you are interested that multiple (possibly independent) consumers get the same message. Your requirement sounds like you are interested that only one of the consumers gets the message, and that's what queues are for, see the Hazelcast documentation for Queues.
来源：https://stackoverflow.com/questions/36709365/consume-message-only-once-from-topic-per-listeners-running-in-cluster