Transactional pointcuts: designation reification and advice of interrelated join points

• Authors: Hossein Sadat-Mohtasham;H. James Hoover
• Venue: GPCE '09 Proceedings of the eighth international conference on Generative programming and component engineering
• Year: 2009

Aspect-oriented mechanisms are characterized by their join point models. A join point model has three components: join points, which are elements of language semantics; "a means of identifying join points"; and "a means of affecting the behaviour at those join points." A pointcut-advice model is a dynamic join point model in which join points are points in program execution. Pointcuts select a set of join points, and advice affects the behaviour of the selected join points. In this model, join points are typically selected and advised independently of each other. That is, the relationships between join points are not taken into account in join point selection and advice. In practice, join points are often not independent. Instead, they form part of a higher-level operation that implements the intent of the developer (e.g. managing a resource). There are natural situations in which join points should be selected only if they play a specific role in that operation. We propose a new join point model that takes join point interrelationships into account and allows the designation of more complex computations as join points. Based on the new model, we have designed an aspect-oriented construct called a transactional pointcut (transcut). Transcuts select sets of interrelated join points and reify them into higher-level join points that can be advised. They share much of the machinery and intuition of pointcuts, and can be viewed as their natural extension. We have implemented a transcuts prototype as an extension to the AspectJ language and integrated it into the abc compiler. We present an example where a transcut is applied to implement recommended resource handling practices in the presence of exceptions within method boundaries.