Separating features in source code: an exploratory study
Gail C. Murphy, Albert Lai, Robert J. Walker, Martin P. Robillard · 2001
Most software system codebases are inflexible. Reconfiguring the software modules comprising a system to add or to delete a feature typically requires substantial effort. This lack of flexibility increases the costs of building variants of a system, amongst other problems. New languages and tools that are being developed to provide additional support for separating concerns in a system show promise to help address this problem. However, applying these mechanisms requires determining how to enable a feature to be separated from the codebase. In this paper, we investigate this problem through an exploratory study conducted in the context of two existing systems: gnu.regexp and jFTPd. The study consisted of applying three different separation of concern mechanisms---Hyper/J TM , AspectJ TM , and a lightweight, lexically-based approach---to separate features in the two packages. In this paper, we report on the study, providing contributions in two areas. First, we characterize the effect different mechanisms have on the structure of the codebase. Second, we characterize the restructuring process required to perform the separations. These characterizations can help software engineering researchers elucidate the design space of using these mechanisms, tool developers design support to aid the separation process, and early adopters apply the techniques. Keywords design space, feature separation, aspect-oriented programming, hyperspaces 1