A tool supporting the re-design of legacy applications

A tool prototype is presented supporting the redesign of existing legacy applications written in COBOL. The prototype is under development in a project with two German companies. The topic of this project is the redesign of existing applications with the aim to migrate parts of legacy applications into a distributed environment. The regarded systems are associated to the domain of business administration software. Existing applications in this domain are often running on a mainframe and users communicate with the application by character oriented terminals. To migrate parts of existing legacy applications into a distributed environment connected by middleware (like products conforming to the CORBA Standard) the structure of many applications must be reengineered because of the lack of interfaces which could act as cutting lines for the parts to separate. As a first step of a migration process we have to reverse engineer an application to get a description on a higher level of abstraction than the source code. The acquired information is stored in form of graphs (call graphs, control flow graphs etc.). The necessary structural changes are performed on the reverse engineering graphs with the help of graph rewriting rules. The transformations on the graphs are connected with source code transformations to couple changes on the abstract graph level with changes on the concrete source code level.