WCF Business Objects Design using Interfaces

Question

Our project requires us to interact with multiple sources for information like Oracle DB, SalesForce, etc. So we want to wrap all the calls under a WCF layer, so that anybody inside the company can use it. For implementing the Domain Objects, this is a consideration:

public class NoteTypeA : INote, INoteTypeA {}
public class NoteTypeB : INote, INoteTypeB {}
public class Customer : INote, ICustomer {}

All the Note classes such as NoteTypeA, NoteTypeB, NoteTypeC all would inherit from INote, however they also would Inherit from INoteTypeA, in the case of NoteTypeA.

I agree with the idea of using INote as it helps you implement Multiple Inheritance. But I don't get the reason behind using INoteTypeA and its looks like anti-pattern for me.

What do you guys think? Does that protect me from a future change? Does it help me smoothly add an out of scope change?

Answer 1

I think will be largely subjective and depend on the implementation.

I usually don't make interfaces for my classes if they are just data containers, but if they have business logic functions, then I do.