Solving the TTC 2011 Reengineering Case with VIATRA2

Automated model transformations play an important role in modern model-driven system engineering in order to query, derive and manipulate large, industrial models. Since such transformations are frequently integrated to design environments, they need to provide short reaction time to support software engineers. The objective of the VIATRA2 (VIsual Automated model TRAnsformations [9]) framework is to support the entire life-cycle of model transformations consisting of specification, design, execution, validation and maintenance. Model representation. VIATRA2 uses the VPM metamodeling approach [8] for describing modeling languages and models. The main reason for selecting VPM instead of a MOF-based metamodeling approach is that VPM supports arbitrary metalevels in the model space. As a direct consequence, models taken from conceptually different domains (and/or technological spaces) can be easily integrated into the VPM model space. The flexibility of VPM is demonstrated by a large number of already existing model importers accepting the models of different BPM formalisms, UML models of various tools, XSD descriptions, and EMF models. Graph transformation (GT) [3] based tools have been frequently used for specifying and executing complex model transformations. In GT tools, graph patterns capture structural conditions and type constraints in a compact visual way. At execution time, these conditions need to be evaluated by graph pattern matching, which aims to retrieve one or all matches of a given pattern to execute a transformation rule. A graph transformation rule declaratively specifies a model manipulation operation, that replaces a match of the LHS graph pattern with an image of the RHS pattern. Transformation description. Specification of model transformations in VIATRA2 combines the visual, declarative rule and pattern based paradigm of graph transformation and the very general, high-level formal paradigm of abstract state machines (ASM) [2] into a single framework for capturing transformations within and between modeling languages [7]. A transformation is defined by an ASM machine that may contain ASM rules (executable command sequences), graph patterns, GT rules, as well as ASM functions for temporary storage. An optional main rule can serve as entry point. For model manipulation and pattern matching, the transformation may rely on the metamodels available in the VPM model space; such references are made easier by namespace imports. Transformation Execution. Transformations are executed within the framework by using the VIATRA2 interpreter. For pattern matching both (i) local search based pattern matching (LS) and (ii)