A system integrator for modeling an object instance of a COBOL data set, the object instance including representations of OCCURS DEPENDING ON clauses or REDEFINE clauses. The system comprises a client interface module, an import module, an object model module and modeler module. The client interface module generates an interface and receives a copybook selection and a set of REDEFINE criteria. The import module receives the copybook selection and imports a copybook from a database. The object model module receives the copybook and the set of REDEFINE criteria, and creates a customized object model for the copybook. The modeler module receives the customized object model and a set of COBOL data, and forms an object instance equivalent to the set of COBOL data, the object instance including representations of a OCCURS DEPENDING ON clause or REDEFINE clause.