This paper reports our experience using AspectJ, a general purpose aspect-oriented extension to Java, to implement distribution and persistence aspects in a web-based information system. This system was originally implemented in Java and restructured with AspectJ. Our main contribution is to show that AspectJ is useful for implementing several persistence and distribution concerns in the application considered, and other similar applications. We have also identified a few drawbacks in the language and suggest some minor modifications that could significantly improve similar implementations. Despite the drawbacks, we argue that the AspectJ implementation is superior to the pure Java implementation. Some of the aspects implemented in our experiment are abstract and constitute a simple aspect framework. The other aspects are application specific but we suggest that different implementations might follow the same aspect pattern. The framework and the pattern allow us to propose architecture-specific guidelines that provide practical advice for both restructuring and implementing certain kinds of persistent and distributed applications with AspectJ.

Abstract. Both, the role concept and aspect-oriented programming are techniques which permit a flexible adaptation of object-oriented constructs and therefore can be used to adjust existing software to new challenges. While the former one is already well known in the object-oriented world, the latter was only recently introduced. Currently, both techniques co-exist without affecting each other and therefore concrete software projects either use the one or the other approach. There are some situations where the result of utilizing the one or the other is approximately the same. Therefore, it is reasonable to analyze each approach in respect to its underlying philosophy and its impact on the implementation level and to compare them on the basis of those observations. This paper discusses the equivalences and differences between the role concept and aspect-oriented programming and reveals potential synergies between both approaches. 1

This paper evaluates the use of AspectJ, a general-purpose aspectoriented extension to Java, to provide adaptive behavior for J2ME applications in a modularized way. Our evaluation is based on the development of a simple but non-trivial dictionary application where new adaptive behavior was incrementally implemented using AspectJ. Our main contribution is to show that the AspectJ language can be used to implement several adaptive concerns, which allow the application to have different behaviors according to changes in its environment.