A MODEL FOR REENGINEERING LEGACY EXPERT-SYSTEMS TO OBJECT-ORIENTED ARCHITECTURE

The migration of existing systems to object-oriented technology is bec oming increasingly important. In this paper, a reengineering model is presented. The goal of the model is to provide a comprehensive method to reengineer non object-oriented systems into object-oriented archite cture. The model consists of three main processes: Reverse engineering merging, and object-oriented development. Reverse engineering extract s requirements and knowledge from an existing software system and redo cuments the system. In the merging process, recovered requirements and knowledge from the reverse engineering process are merged with new re quirements and knowledge. The merging process removes redundancy, chec ks for inconsistency, and detects incompleteness. In the object-orient ed development, a reengineered system is developed using an object-ori ented software development method. This research demonstrates that suc cessful reengineering to object-oriented architecture can be achieved by using requirements and knowledge from the original system as a basi s for developing the object-oriented system. The model proved to be us eful where a paradigm shift is needed. The effectiveness of the model was demonstrated by converting a legacy non object-oriented software s ystem (implemented in C) into an object-oriented system (implemented i n Smalltalk). A set of tools was built to support the model. We also i dentify guidelines that facilitate the transformation of legacy softwa re systems into object-oriented systems. (C) 1997 Elsevier Science Ltd .