Sort-based refactoring of crosscutting concerns to aspects

Crosscutting concerns in object-oriented programming hinder evo-lution because of their symptoms: tangling and scattering. To ben-efit 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 doc-umenting 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 sec-ond 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 en-countered ones: Role Superimposition and Consistent Behavior. The refactoring towards aspects of concerns of these sorts is illus-trated on an open source application (JHotDraw). 1