Extracting Use Case Scenarios and Domain Models from Legacy Software

Developing a new software system based on legacy software is a labor-intensive process. The main problem lies in preserving the application and domain (business) logic. This paper presents an approach to automate the process of extracting this logic, together with accompanying domain definitions. The approach is based on recording and processing the legacy system behaviour, observable through its user interface. The recovered application logic is represented with use case scenarios having precise sentences describing user-system interactions. These scenarios are tightly linked with domain models which are also created. The presented approach is supported by a tool chain. The central idea is to use a standard test automation system to capture test scripts. These scripts are then processed by a dedicated translation tool and translated into constrained natural language models. These models are machine processable, which allows for further automatic transformations even down to code. The paper presents the results of a case study where the approach and tools were used to migrate an old desktop system to a modern web technology application.