Question

I have a method ‘ABC’ that does some stuff. The ABC method is called from another method, method XYZ. Where should the data validation of the input values occur?

Should I validate in XYZ before even calling ABC? If it’s bad data method ABC won’t even be called.

Or, should I validate in ABC?

Or, validate in both locations?

Answer 1

It depends.

If ABC is only ever called by XYZ then you can validate by XYZ.

If ABC has visibility outside of XYZ (for example it’s a public method, or an internal one) then you should validate in ABC.

If it’s a critical function (ABC = AtomicBombControl) then validate everywhere you can.