Sort-based refactoring of crosscutting concerns to aspects

Crosscutting concerns in object-oriented programming hinder evolution because of their symptoms: tangling and scattering. To benefit from the modularisation capabilities for crosscutting concerns provided by aspect-oriented programming (which prevent tangling and scattering) aspect-introducing refactoring can be used. The first step in aspect-introducing refactoring is identifying and documenting crosscutting concerns in existing code. The second step is refactoring the identified concerns to aspects. This paper describes a tool called SAIR that can perform the second step of the aspect-introducing refactoring. For the first step, documenting, SAIR uses crosscutting concern sorts. Of the various possible sorts, SAIR currently supports the two most commonly encountered ones: Role Superimposition and Consistent Behavior. The refactoring towards aspects of concerns of these sorts is illustrated on an open source application (JHotDraw).