Specifying and Adapting Object Behavior During System Evolution

Object-Oriented software engineering must address new issues during system evolution, namely the effects of class evolution on existing class methods. A Class Dictionary Graph describes the class structure and relationships of a given domain. A Propagation Pattern deenes object behavior by describing responsibilities among a group of collaborating classes. The behavior described in a Propagation Pattern is mapped onto the class structure deened in a Class Dictionary Graph, and the appropriate C++ code is generated. Class structures evolve in many ways. This paper details the eeects of class evolution on the object behavior deened in existing Propagation Patterns, and describes the requirements for adapting Propagation Patterns during class evolution, as compared to the eeorts of maintaining C++ code.