Modifying Contracts with Larissa Aspects

This paper combines two successful techniques from software engineering, aspect-oriented programming and design-by-contract, and applies them in the context of reactive systems. For the aspect language Larissa and contracts expressed with synchronous observers, we show how to apply an aspect asp to a contract C and derive a new contract C′, such that for any program P which fulfills C, P with asp fulfills C′. We validate the approach on a medium-sized example.