Decomposing legacy programs: a first step towards migrating to client-server platforms

A solution to the problem of salvaging the past investments in centralised, mainframe-oriented software development, while keeping competitive in the dynamic business world, consists of migrating legacy systems towards more m odern environments, in particular client-server platforms. However, a migra tion process entails costs and risks that depend on the characteristics of both the architecture of the source system and the target client-server pla tform. We propose an approach to program decomposition as a preliminary step for t he migration of legacy systems. A program slicing algorithm is defined to i dentify the statements implementing the user interface component. An intera ctive re-engineering tool is also presented that supports the software engi neer in the comprehension of the source code during the decomposition of a program. The focus of this paper is on the partition of a legacy system, wh ile issues related to the re-engineering, encapsulation, and wrapping of th e legacy components and to the definition of the middleware layer through w hich they communicate are not tackled. (C) 2000 Elsevier Science Inc. All r ights reserved.