Pattern-Based Model Transformation Using QVT

A design pattern addresses a recurring design problem by providing a proven solution for reuse in software development. However, due to the informal nature of prevailing pattern descriptions, it is difficult to reuse design patterns in practice. There has been much work on tool support for pattern reuse. However, the existing work focuses on only the solution domain of a pattern, leaving largely the problem domain unaddressed which is an important aspect in determining pattern applicability. Also, the existing work uses non-standardized techniques, which makes it difficult to adopt. In this work, we present a novel approach for applying design patterns using Query/View/Transformation (QVT), a de-facto standard for model transformation. In the approach, we make use of both the problem domain and solution domain of a design pattern for checking pattern applicability and verifying pattern conformance. The domains are defined at the metamodel level and mapped each other for a base to define QVT transformation. We demonstrate the approach using the Visitor design pattern applied to an open source drawing tool.