Inheritance

Abstract

This chapter presents the use of the principle of generalisation/specialisation in conceptual modelling. Generalisation/specialisation is an abstraction principle allowing the definition of a class as a refinement of another class. The more general class is called a supertype, generalisation or parent class and the refined class is then called a subtype, specialisation or child class. With the advent of object-oriented analysis methods, many different ways of how to concretely use the generalisation/specialisation hierarchy in modelling were proposed. Most of the time, however, these proposals were not well integrated with the behavioural aspects in object-oriented modelling. Also today the definition of the generalisation/specialisation relationship is mostly formulated in the context of a static model only. In this chapter we will first address the definition of the concept from the perspective of the class diagram. Subsequently, Sect. 8.2 addresses the behavioural aspects of inheritance. To conclude Sect. 8.3 will address the question on when to use or not to use this construct.