Extracting Error Handling to Aspects: A Cookbook

It is usually assumed that exception handling code can be better modularized by the use of aspect-oriented programming (AOP) techniques. However, recent studies argue that the ad hoc use of AOP can be detrimental to the quality of a system. When refactoring exception handling code to aspects, developers and maintainers need to follow clear and simple principles to obtain a well-structured system design. Otherwise, typical problems that stem from poorly designed/implemented error handling code will arise, e.g. resource leaking and swallowed exceptions. In this paper, we propose a classification for error handling code based on the factors that we found out have more influence on its aspectization. Moreover, we present a scenario catalog comprising combinations of these factors and analyze how these scenarios positively or negatively affect the task of aspectizing exception handling. We evaluated the proposed catalog through a case study where we used it to guide the aspectization of exception handling in two real systems.