Deriving an object model from legacy Fortran code

Abstract

The practice of software development continues to shift towards the use of object oriented approaches. The motivation for this trend is the benefits attributed to object oriented software, including improved maintainability. As organizations develop new object oriented software, they face the problem of maintaining their older software. How can existing non objected oriented software benefit from this new software engineering technology? The paper presents a nine step process for deriving an object model from existing unstructured FORTRAN source code. Both top down and bottom up approaches are used to derive objects, classes, class attributes and methods, and relationships among classes. This process can be used within a reengineering project to convert legacy FORTRAN code into a new object oriented implementation written in a language such as C++. Experience with using this process is also described.