Abstract. Many modeling languages share some common concepts and principles. For example, Java, MOF, and UML share some aspects of the concepts of classes, methods, attributes, and inheritance. However, model transformations such as refactorings specified for a given language cannot be readily reused for another language because their related metamodels may be structurally different. Our aim is to enable a flexible reuse of model transformations across various metamodels. Thus, in this paper, we present an approach allowing the specification of generic model transformations, in particular refactorings, so that they can be applied to different metamodels. Our approach relies on two mechanisms: (1) an adaptation based mainly on the weaving of aspects; (2) the notion of model typing, an extension of object typing in the model-oriented context. We validated our approach by performing some experiments that consisted of specifying three well known refactorings (Encapsulate Field, Move Method, and Pull Up Method) and applying each of them onto three different metamodels (Java, MOF, and UML).

Model transformations written for an input metamodel may often apply to other metamodels that share similar concepts. For example, a transformation written to refactor Java models can be applicable to refactoring UML class diagrams as both languages share concepts such as classes, methods, attributes, inheritance. Deriving motivation from this example, we present an approach to make model transformations reusable such that they function correctly across several similar metamodels. Our approach relies on these principal steps: (1) We analyze a transformation to obtain an effective subset of used concepts. We prune the input metamodel of the transformation to obtain an effective input metamodel containing the effective subset. The effective input metamodel represents the true input domain of transformation. (2) We adapt a target input metamodel by weaving it with aspects such as properties derived from the effective input metamodel to ultimately make it a subtype of the effective input metamodel. The subtype property ensures that the transformation can process models conforming to the target input metamodel without any change in the transformation itself. We validate our approach by adapting well-known refactoring transformations (Encapsulate Field, Move Method, and Pull Up Method) written for an in-house domain-specific modelling language (DSML) to three different industry standard metamodels (Java, MOF, and UML).