Researches And Implement On Object Extracting Of Legacy Systems Written In Conventional Procedural Language

Independence of module is bad and coupling between modules is always high in legacy systems written in conventional procedural languages. Transforming legacy systems into equivalent object-oriented systems makes software more maintainable,reliable and understandable. However,there is no concept directly corresponding to objects in non object-oriented systems. A lot of object-extraction approaches for extracting objects from legacy systems into object-oriented systems. The paper did a lot of in-depth research about object-extracting approach on module features. An subprogram-type graph is introduced to represent the relation between subprograms and types in programs. Several module cohesion metrics are discussed,and the effects of adding a subprogram to or deleting a subprogram from a module are analyzed based on module cohesion. An object-extracting algorithm is proposed.