Reengineering using design patterns

Starting from a legacy system, originally developed in C and using text files, we first conducted a reverse engineering of this system to obtain its object-oriented analysis model. Then, in a process that is called segmentation, we restructured the code, changing all data structures to abstract data types and procedures to methods, eliminating all data access anomalies. This paper presents an experiment in which part of the segmented code was reengineered to an object-oriented language (Java) and the text files were replaced by a relational database. We show how design patterns have been used to link the database with the object-oriented concepts of Java. We also report a maintenance experiment that compares maintainability of the legacy system, the segmented system, and the object-oriented version.