Reuse of off-the-shelf components in C2-style architectures

Abstract

Reuse of large-grain software components offers the potential for significant savings in application development cost and time. Successful comuonent reuse and substitutability depends both on qualities of the &mponents reused as well as the sofiware context in which the reuse is attempted. Disciplined approaches to the structure and design of software applications offers the potential of providing a hospitable setting for such reuse+ We present the results of a series of exercises designed to determine how well "offthe-shelf" components could be reused in applications designed in accordance with the C2 software architectural style. The exercises involved the reuse of two user-interface constraint solvers, two graphics toolkits, a World Wide Web browser, and a persistent object manager. A subset of these components was used to construct numemus variations of a single application (thus an application family). The exercises also included construction of a simple development environment for locating and downloading a component off the Web and incorporating it into an application. The paper summarizes the style rules that facilitate reuse and presents the results from the exercises. The exercises were successful in a variety of dimensions; one conclusion is that the C2 style offers significant reuse potential to application developers. At the same time, wider trials and additional tool support are needed' Index Terms -software reuse, architectural styles, messagebased architectures, component-based development, graphical user interfaces (GUI).