A Case for a Uniform Mechanism for Variability Management

Having set up reusable core assets for a software Product Line (SPL), it is a common practice to apply variation mechanisms to manage variant features. As each variation mechanism can handle only certain type of variability, multiple variation mechanisms are often employed, such as conditional compilation, configuration parameters or build tools. Our earlier study of an SPL at Fudan Wingsoft Ltd revealed potential scalability problems of multiple variation mechanisms. As a product line grows, it becomes increasingly difficult to understand features that affect many core assets, at many variation points, and to coordinate changes required at multiple variation points. As a remedy to the above problems, in the follow-up study we replaced variation mechanisms originally used in the Fudan Wingsoft product line, with a single, uniform variation mechanism of XVCL. This paper provides a proof-of-concept that commonly used variation mechanisms can indeed be superseded by a subset of XVCL, in a simple and natural way. We describe the essence of XVCL solution, and evaluate the benefits and trade-offs involved in replacing multiple variation mechanisms with uniform one.