Re-factoring middleware systems: A case study

Abstract

Aspect oriented programming brings us new design perspectives since it permits the superimpositions of multiple abstraction models on top of one another. It is a very powerful technique in separating and simplifying design concerns. In this paper, we provide detailed descriptions of our aspect oriented re-factoring of ORBacus, an industrial strength CORBA implementation. The re-factored features are the dynamic programming interface, support for portable interceptors, invocations of local objects. Their associated IDL-level re-factorization is addressed by an aspect-aware IDL compiler. In addition, we present the quantification for the changes in terms of both the structural complexity and the runtime performance. The aspect oriented re-factorization proves that AOP is capable of composing non-trivial functionality of middleware in a superimposing manner. The final "woven" system is able to correctly provide both the fundamental functionality and the "aspectized" functionality with negligible overhead and leaner architecture. Furthermore, the "aspectized" feature can be configured in and out during compile-time, which greatly enhances the configurability of the architecture. © Springer-Verlag Berlin Heidelberg 2003.