Optimizing Constraint Weaving in Model Transformation with Structural Constraint Specification

Model-Driven Architecture (MDA) as a model-based approach to software development facilitates the synthesis of application programs from models created using customized, domain-specific model processors. MDA model compilers can be realized by graph rewriting-based model transformation. In Visual Modeling and Transformation System (VMTS), metamodel-based rewriting rules facilitate to assign OCL constraints to model transformation steps. This approach supports validated model transformation. The goal is to validate not only the individual transformation steps, but the whole transformations as well. Unfortunately, the validation introduces a new concern that often crosscuts the functional concern of the transformation steps. To separate these concerns and make them reusable, an aspect-oriented solution is presented for constraint management. This paper introduces a new type of aspect, the constraint aspect to separate the crosscutting constraints from model transformation steps. Moreover, algorithms are given to create and weave constraint aspects to model transformation steps prior to the execution of the transformation. The presented method results in a more efficient and optimized weaving, furthermore, we can require that not only a single transformation step, but a whole transformation validates, preserves or guarantees certain properties about the output of the transformation.