Messaging Model
Apache ActiveMQ Artemis messaging model is build on top of three main concepts: addresses, queues and routing types.
Address
The general idea behind the messaging model of Apache ActiveMQ Artemis is that producers never send messages directly to queues. Actually, a producer is unaware whether a message will be delivered to any queue at all. Instead, the producer can only send messages to an address. The address represents a message endpoint. It receives messages from producers and pushes them to queues. The address knows exactly what to do with the message it receives. Should it be appended to a single or to many queues? Or maybe should it be discarded. The rules for that are defined by the routing type.
Routing Types
There are two routing types available in Apache ActiveMQ Artemis: Anycast and Multicast. The address can be created with either or both routing types.
When the address was created with Anycast routing type all messages send to this address will be evenly distributedanycast-message-distribution among all the queues attached to this address. With Multicast routing type every queue bound to the address receives its very own copy of a message. Had the message been pushed to the queue, it can be picked up by one of the consumers attached to this particular queue.
Further Reading
The Apache ActiveMQ Artemis address model is described in detail (with examples using ArtemisNetClient) in this article.
Footnotes:
- Messages will be distributed using Round-robin distribution algorithm.↩