ECOOP 2012 – Object-Oriented Programming

Abstract

Class diagrams (CDs), which specify classes and the relationships between them, are widely used for modeling the structure of object-oriented systems. As models, programs, and systems evolve over time, during the development lifecycle and beyond it, effective change management is a major challenge in software development, which has attracted much research efforts in recent years. In this paper we present cddiff , a semantic diff operator for CDs. Unlike most existing approaches to model comparison, which compare the concrete or the abstract syntax of two given diagrams and output a list of syntactical changes or edit operations, cddiff considers the semantics of the diagrams at hand and outputs a set of diff witnesses , each of which is an object model that is possible in the first CD and is not possible in the second. We motivate the use of cddiff , formally define it, and show how it is computed. The computation is based on a reduction to Alloy. The work is implemented in a prototype Eclipse plug-in. Examples show the unique contribution of our approach to the state-of-the-art in version comparison and evolution analysis.