Queue for messages from two sources in Apache Camel with chronological order

Question

I would like to realize next scenario in Apache Camel (included in JBoss Fuse):

I have two systems, both of them produce events stored in database separately. Now I need to read events from this event tables and put them as messages in queue (realized by ActiveMQ). But what is really important I need to keep chronological order (creation time) of events in this queue, no matters where event was created.

I am looking for solution, which maximally uses components and patterns from Camel framework, of course I can realize the reading mechanism outside of Camel (pure Java), but I prefer Camel solution.

Thanks a lot for any idea!

Answer 1

I think you just want to pop the messages onto a seda queue and use a resequencer to merge them back into order.

from("--database1--")
    to("seda:resequencer")

from("--database2--")
    to("seda:resequencer")

from("seda:resequencer")
    .resequence(header("date")).batch().timeout(5000L)
    .to("activemq:...")

You will need to pay attention to the timeout settings and what is appropriate.

(Note: I haven't tested this code, so please tage it as a suggestion).