A Systematic Aspect-Oriented Refactoring and Testing Strategy, and its\n Application to JHotDraw

Aspect oriented programming aims at achieving better modularization for a\nsystem's crosscutting concerns in order to improve its key quality attributes,\nsuch as evolvability and reusability. Consequently, the adoption of\naspect-oriented techniques in existing (legacy) software systems is of interest\nto remediate software aging. The refactoring of existing systems to employ\naspect-orientation will be considerably eased by a systematic approach that\nwill ensure a safe and consistent migration.\n In this paper, we propose a refactoring and testing strategy that supports\nsuch an approach and consider issues of behavior conservation and (incremental)\nintegration of the aspect-oriented solution with the original system. The\nstrategy is applied to the JHotDraw open source project and illustrated on a\ngroup of selected concerns. Finally, we abstract from the case study and\npresent a number of generic refactorings which contribute to an incremental\naspect-oriented refactoring process and associate particular types of\ncrosscutting concerns to the model and features of the employed aspect\nlanguage. The contributions of this paper are both in the area of supporting\nmigration towards aspect-oriented solutions and supporting the development of\naspect languages that are better suited for such migrations.\n