Using Petri Nets for Specifying Active Objects and Generative Communication

Abstract

A majority of the research committee dealingwith the development of advanced future software systems appears to agree upon the requirements that a software modellingapproac h should meet. In short, it should enable a “cost-effective software development for open parallel and distributed systems”. One concept that is intrinsicly involved is agent-based modelling techniques, which combine object technology with concurrency.

Most current approaches to combiningob jects and concurrency fail to provide a well-founded integration of the conflicting dimensions in advanced object-oriented environments, such as classes, inheritance, concurrency and types.

This paper first elaborates on the set of requirements of an advanced software development approach. Thereafter, it discusses an approach for modelling, implementingand reasoningup on such systems. It is based on principles of concurrent object-orientation, generative communication - in particular the coordination language called Objective Linda - and Petri nets. The main contribution of this paper is to provide formal de.- nitions of a Petri net formalism that is used to provide (1) semantics for the Objective Linda language, and (2) modelling the internal behaviour of concurrent objects.

The approach is illustrated through a case study, proposed by C. Sibertin- Blanc. The case is a variant of the well known diningphilosophers problem, called “the Hurried Philosophers” problem.

Research Assistant of the Belgian Fund for Scientific Research