For Java I found this web-page which explains how to do it. It is about a class with one nested class
https://developers.google.com/protocol-buffers/docs/javatutorial
From the tutorial you mention:
'Don't go looking for facilities similar to class inheritance, though – protocol buffers don't do that.'
actually, you don't need to do that, you can just map to protobuf from inheritance-flattened form of the model classes. That can easily be generated from a model - UML tools, do it, BMM supports it, I think it should also be easy via Java reflection.
- thomas
Good idea, there is some information on the subject on internet.
Bert