REUSABLE SOFTWARE COMPONENTS

The chapter focuses on consolidating important recent technical advances that help in making reusable software components more feasible. It describes a general model of software structure and then uses that model to clarify several key ideas, including software component. The model leads to a natural vision of the likely scope of a mature software-components industry and highlights the technical issues such as software specification, parameterization of behavior, and certification of correctness of component implementations. The chapter emphasizes that the 3C reference model has the potential to become the accepted basis for discourse on reusable software components among members of the reuse community. The 3C model defines and distinguishes three ideas: concept, content, and context. The 3C model of software structure makes no commitment as to whether any component is reused. It also makes no commitment as to the source of the components, i.e., whether they are purchased piece-parts or leftovers from a past company project or developed as custom components for the current project. The model thus provides a framework in which reusable components can be studied but it does not mandate reuse. The chapter describes both general and specific guidelines to direct designers of reusable software components toward superior abstract designs that have efficient implementations. It also discusses the influences of programming-language mechanisms on component reuse and the influences of component reuse on programming-language design. © 1991 Academic Press Inc.