Better way of creating response objects

[itszootime]

If I want to add data to a returned JSON object at the moment (e.g. for validation), I have to add a field to the class doing the calculation, associated getter, add a field to the response class, associated getting and setter, and finally the static from method.

It would be possible to have the calculation class implement a Returnable interface, and have some sort of annotation to specify fields to return? Or use the in-built Gson features for specific field serialization. It will most likely need the interface so Gson can identify when it needs to add a type: 'SomethingResponse' field.