Abstract
For a variety of reasons, today's middleware systems are highly complex. This complexity surfaces internally in the middleware construction, and externally in the programming models supported and features offered. We believed that aspect-orientation could help with these problems, and undertook a case study based on members of an IBMr® middleware product-line. We also wanted to know whether aspect-oriented techniques could scale to commercial project sizes with tens of thousands of classes, many millions of lines of code, hundreds of developers, and sophisticated build systems. This paper describes the motivation for our research, the challenges involved, and key lessons that we learnt in refactoring both homogeneous and heterogeneous crosscutting concerns in the middleware. Copyright 2004 ACM.