Managing Class Evolution in Object Oriented Systems Managing Class Evolution in Object Oriented Systems Managing Class Evolution in Object Oriented Systems 8. Change Avoidance Managing Class Evolution in Object Oriented Systems Change Propagation

Software components developed with an object-oriented language undergo considerable repro-gramming before they become reusable in a wide range of applications or domains. Tools andmethodologies are therefore needed to cope with the complexity of designing, updating and reor-ganizing vast collections of classes. This paper describes several techniques for controllingchange in object-oriented systems, illustrates their functionality with selected examples and dis-cusses their advantages and their limitations. As a complement to traditional approaches like ver-sion management, we propose new algorithms for automatically restructuring a hierarchy whenclasses are added to it. These algorithms not only help in handling modifications to libraries ofsoftware components, but they also provide useful guidance for detecting and correcting improp-er class modelling.