Question

We have a distributed system, in which two components: A and B, communicate by sending to each other some transport object, which is very large and complex.
Currently, the object is simply serialized into the wire by A and is read by B.

Now we are required to support a scenario in which B’s version is advanced while A’s version stays the same, which means B must have versioning capabilities to be able to process older versions of the communication object.

What are the common ways to do this?
(We use Java)

Answer 1

You can have different versions of the method – one that takes the old version and that A uses.

This method can also act as a translator into the new version (anti-corruption layer, if you will) and utilise a new method that all new clients should use.

Basically, your B should be able to read both versions – internally the best way is to translate the old version to the new one and use that throughout the codebase of B.