Transitive ordering of messages in Akka Actors

Question

Is there any simple way to enforce transitive ordering of messages in Akka?

For example I have

• A sending M1 to C
• A sending M2 to B
• B forwards M2 to C

How do I ensure C gets (or interprets) M1 before M2 in a simple way?

Answer 1

There are a few of ways you could do this:

1. Have C send a reply to A when it receives M1 and delay sending M2 to B before the reply is received.

2. Send M2 to C and have C forward it to B

3. Put a flag in M2 to say that it depends on M1 and have C stash M2 if it arrives before M1