Reusing software may greatly increase the productivity of software engineers and improve the quality of developed software. Software component libraries have been suggested as a means for facilitating reuse. A major difficulty in designing software libraries is in the selection of a component representation that will facilitate the classification and the retrieval processes. Using formal specifications to represent software components facilitates the determination of reusable software because they more precisely characterize the functionality of the software, and the well-defined syntax makes processing amenable to automation. This paper presents an approach, based on formal methods, to the classification, organization and retrieval of reusable software components. From a set of formal specifications, a two-tiered hierarchy of software components is constructed. The formal specifications represent software that has been implemented and verified for correctness. The lower-level hierarchy is created by a subsumption test algorithm that determines whether one component is more general than another; this level facilitates the application of automated logical reasoning techniques for a fine-grained, exact determination of reusable candidates. The higher-level hierarchy provides a coarse-grained determination of reusable candidates and is constructed by applying a hierarchical clustering algorithm to the most general components from the lower-level hierarchy. The hierarchical organization of the software component specifications provides a means for storing, browsing, and retrieving reusable components that is amenable to automation. In addition, the formal specifications facilitate the verification process that proves a given software component correctly satisfies the current problem. A prototype browser that provides a graphical framework for the classification and retrieval process is described.
Creating Reusable Software Component from Object-Oriented Legacy System through Reverse Engineering.
