Bidirectional transformations with QVT-R: A case study in round-trip engineering UML class models and java source code

Model-driven software engineering has become more and more important during the last few years. Model transformations constitute the core essence of model-driven development. Throughout the years, the concept of unidirectional model transformations and corresponding tool support has become mature and usable. Transformations of this kind are widely used in model-driven development, for forward or reverse engineering or mainly for code generation. Bidirectional transformations, on the other hand, aim to provide support for (incrementally) transforming one or more source models to one or more target models and vice versa from only one transformation description. However, they seem to be rarely used in model-driven software development although modelers need round-trip support between the different stages of development models. In this paper we present a QVT implementation of a bidirectional model transformation. Our case study keeps UML class diagrams consistent with a Java model during round-trip engineering and thereby shows a real world application. The results and experiences gained in this case study are discussed in detail.