Message Router Use Case

I am new to Messaging and Integration. As I am trying to understand how Apache Camel makes EIP easy, Message Router caught my attention to a specific scenario where it consumes a message from one queue and transfers to some other queue based on a predicate.

Here are my questions:

• Why use Message Router to perform this task?
• Why not the message Producer directly send the message to the right Queue/Destination?
• Why not the Consumer can rely on Message Selectors to do the same?

Can someone share your thoughts on real life use cases?

Well, your questions are more about SoC than messaging.

• The Message Router is an EIP that can perform this task well and with Camel it is also very easy to implement, but as you write, there are other possibilities too.

• If the message producer (client) sends messages directly to final destinations, it must know about all possible destinations. It must also be changed whenever a destination is added/removed or changed. This is tight coupling and in most situations not desirable.

• If the message receiver(s) consume(s) with message selectors, the client can send all messages to the same queue. This is totally OK, you can implement individual consumers with different selectors. The selector feature of the Broker basically enables you to "divide a queue into multiple queues".

So if you want to implement and run an intermediate integration component between the client and the receivers, you can use the Message Router in this component.

If you want to omit this integration component, you can use message selectors to implement the receivers individual and de-coupled from each other.