Writing Reusable Feature Programs with the Feature Language Extensions

One of the most difficult tasks in the development of interacting features is that it requires a labor intensive and error prone process of examining and modifying code. The feature code typically ends up scattered and not reusable. In this paper, we describe a set of programming language extensions that will allow the programmer to develop interacting features as reusable program modules even though the features may change the execution flow of each other. The programmer uses these language extensions to specify nonprocedural program units, organize the program units into reusable features and integrate features into executable feature packages. The language extensions enable an automatic procedure to detect interaction condition among features; the programmer can resolve the interaction without changing feature code. Furthermore, the programmer may package different sets of features and resolve their interactions differently to meet different user and market needs. These language extensions have been implemented on Java and used to develop a prototype telephony system.