Integration of Visual Contracts and Model Transformation for Enhanced MDE Development

Model transformations are an important aspect of Model-Driven Engineering as models throughout the software development process are transformed and refined until, finally, application code is generated. However, model transformations are complex to build, maintain, and verify for correctness. We propose the combination of visual contracts, an implementation independent approach for specifying correctness requirements for verification purposes, with operator-based model transformation execution to integrate both the specification of transformation requirements and the transformations themselves within the same framework. The graphical operator-based notation is used to define both the constraints of a contract and the transformation definition. This allows reuse of operators between the two and maintains implementation independence as the operators can be directly executed or compiled to other model-transformation languages. To illustrate the concept, we report on a prototype integration of visual contracts with our our existing operator-based model transformation framework and applied it in the law-enforcement context to transform relational data sources into Elasticsearch for multisource analytics.