Modular Contracts With Procedures, Annotations, Pointcuts and Advice

There are numerous mechanisms for modularizing design by contract at the source code level. Three mechanisms have been the main focus of attention, metadata annotations, pointcuts and advice. The latter two are well-known aspect-oriented programming mechanisms, and according to the literature, fare better in achieving contract modularization. However, previous efforts aimed at supporting contract modularity actually hindered it. In this paper, the authors report an enhanced use of pointcuts and advice, and show how CROSScut Programming Interfaces (XPIs) can significantly improve contract modularity.