Solving the TTC 2011 Reengineering Case with Henshin

Models are a helpful means of representing different aspects of a software system more abstractly to improve comprehension. In the modeling community, the Eclipse Modeling Framework (EMF) [6] has evolved to a widely used technology. While EMF itself provides modeling and code generation capabilities, extensions such as the Java Model Parser and Printer (JaMoPP) allow the translation of Java source code into equivalent EMF model representations. This paves the way to exploit model-to-model transformations in order to translate source code models into other possibly more abstract representations. HENSHIN [1, 2] is a declarative transformation language and tool environment for in-place EMF model transformation. In-place means that EMF models are modified directly without prior copying or conversion. HENSHIN is able to handle static and dynamic EMF models, i.e., those with underlying generated model code and those without. The transformation concepts base on the well-founded theory of algebraic graph transformation with pattern-based rules as main artifacts, extended by nestable application conditions and attribute calculation. Moreover, nestable transformation units with well-defined operational semantics paired with parameter passing allow to define control and object flows. In the HENSHIN tool environment, transformations can be specified using several (graphical) editors. In the following, a representative selection of the complete solution of the Transformation Tool Contest (TTC) 2011 case study Model Transformations for Program Understanding: A Reengineering Challenge [3] is described. The goal of this case study is to translate JaMoPP-based Java models into corresponding simple state machine models . This translation is implemented using HENSHIN.