Quality of Merge-Refactorings for Product Lines

In this paper, we consider the problem of refactoring related software products specified in UML into annotative product line representations. Our approach relies on identifying commonalities and variabilities in existing products and further merging those into product line representations which reduce duplications and facilitate reuse. Varying merge strategies can lead to producing several semantically correct, yet syntactically different refactoring results. Depending on the goal of the refactoring, one result can be preferred to another. We thus propose to capture the goal using a syntactic quality function and use that function to guide the merge strategy. We define and implement a quality-based mergerefactoring framework for UML models containing class and statechart diagrams and report on our experience applying it on three case-studies.