The aim of our work is the modelling and design of information systems in the object-oriented setting. An object-oriented specification covers structural as well as behavioural aspects of the system.

Abstract not found

In hierarchical system design, refinement allows to incrementally increase the level of detail in the system description. Several notions of refinement have been investigated in process theory and in object-oriented frameworks. From a process algebraic viewpoint, an object as the basic unit of structure and control can be understood as a process. Then action reification - the replacement of actions by transactions in object-oriented specification - corresponds to action refinement in process algebra where actions are replaced by process terms. Questions of distributed control, synchronisation, and serialisability translate naturally from the object-oriented framework into process theory and vice versa. In both frameworks, correctness critera exist which prevent the use of refinements if they would cause serious problems in synchronisation and distributed control. We compare an object-oriented and a process algebraic approach for action refinement, both based on an event structure semantics. We show how restrictions ensuring correct refinement known from the process algebraic framework can be applied in the object-oriented approach. Moreover, results from process theory on the preservation of system properties under refinement now become accessible for verification in the object-oriented setting. All concepts are illustrated by a small case study.

Reification is a popular technique to reduce complexity of the software design process. This technique has to be re-investigated for the comprehensive objectoriented approach. Object-oriented specifications comprise structure and behavior of systems. Due to this sophisticated idea two kinds of reification appear: data reification and action reification. In this paper we present an approach to incorporate action reification in object-oriented specification. A logic is defined which serves as a domain to translate specifications. Moreover, we define a language for reification and formalize it with the logic. Interpretation structures of this logic are labelled event structures which are introduced briefly and satisfaction of formulas is defined. With an example we explain our ideas of correct reification and establish a reification condition. Finally, we show how data reification is uniformly included in our approach.

In this paper we investigate the notion of transaction in object-oriented specification.

Published in collaboration with the

Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.5.4 Special Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.6 Semantics of Programming Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.1 Semantics of Ada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.2 Action Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.7 Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.1 Early Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.2 Recent Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . 55 4.7.3 The Common Framework Initiative. . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5 Methodology 57 5.1 Development Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.1.1 Applica...