Enforcing information hiding in interface specifications: a client-aware checking approach

Abstract

Information hiding is an established principle that controls which parts of a module are visible to non-privileged and privileged clients (e.g., subclasses). This aids maintenance because hidden implementation details can be changed without affecting clients. The benefits of information hiding apply not only to code but also to other artifacts, such as specifications. Unfortunately, contemporary formal interface specification languages and their respective runtime assertion checkers (RACs) are inconsistent with information hiding rules because they check assertions in an overly-dynamic manner on the supplier side. We explain how overly-dynamic RACs compromise information hiding and how our client-aware checking technique allows these RACs to use the privacy information in specifications, which promotes information hiding.