A Disciplined Approach to the Maintenance of the Class Hierarchy

Encapsulation and the definition of objects in the respective classes facilitates the modification of object-oriented systems, but the class hierarchy may also be a source of problems. First, before changing the definition of a class, the analyst must verify that the change is coherent with regard to subclasses of the class recursively. Second, the reusability of the properties and the uniformity and functionality of the system can be increased by defining the properties as high as possible in the class hierarchy. Consequently, the maintainer has to navigate up and down while investigating and implementing the changes in the class hierarchy. In this work it is shown that the maintenance is a disciplined process that can be well supported with object-oriented algorithms. Index Terms object-oriented, maintenance, object, class, class hierarchy, inheritance, reuse.