Weaving Aspect-Oriented Constraints into Metamodel-Based Model Transformation Steps

Graph rewriting is a widely used approach to model transformation. In general, graph rewriting rules parse graphs only by topological concerns, but they are not sophisticated enough to match a graph with a node which has a special property. In case of diagrammatic languages, such as the Unified Modeling Language (UML), the exclusive topological parsing is found to be not enough. To define the transformation steps in a more refined way additional constraints must be specified, which ensures the correctness of the attributes among others. Dealing with OCL constraints provides a solution for the unsolved issues. Often, the same constraint is repetitiously applied in many different places in a transformation. It would be beneficial to describe a common constraint in a modular manner, and to designate the places where it is to be applied. This paper presents the problem of the crosscutting constraints in graph transformation steps, provides an aspect-oriented solution for it, and introduces the weaving algorithms used to propagate aspect-oriented constraints to graph transformation steps.