Life-cycle inheritance: A petri-net-based approach

Abstract

Inheritance is one of the key issues of object-orientation. The inheritance mechanism allows for the definition of a subclass which inherits the features of a specific superclass. This means that methods and attributes defined for the superclass are also available for objects of the subclass. Existing methods for object-oriented modeling and design from the dynamic behavior of objects when defining inheritance. Nevertheless, it would be useful to have a mechanism which allows for the inheritance of dynamic behavior. This paper describes a Petri-net-based approach to the formal specification and verification of this type of inheritance. We use Petfi nets to specify the dynamics of an object class. The Petrinet formalism allows for a graphical representation of the life cycle of objects which belong to a specific object class. Four possible inheritance relations are defined. These inheritance relations can be verified automatically. Moreover, four powerful transformation rules which preserve specific inheritance relations are given. To illustrate the relevance of these results, the application to workflow management is demonstrated.