A Case Study in Incremental Architecture-Based Re-engineering of a Legacy Application

Without rigorous software development and maintenance, software tends to lose its original architectural structure and become more difficult to understand and modify. ArchJava, a recently proposed implementation language which embeds a component-and-connector architectural specification within Java implementation code, offers the promise of preventing the loss of architectural structure. We describe a case study in which we incrementally re-engineer an existing implementation with an eroded architecture to obtain an ArchJava implementation that more closely matches an idealized architecture. Building on results from similar case studies, we chose an application consisting of over 16,000 source lines of Java code and 80 classes that exhibited many characteristics of real-world legacy applications. We describe our process, some lessons learned, as well as some perceived limitations with the tools, techniques and languages we used.