Pn-tox: a Paradigm and Development Environment for Object Concurrency Speciications

In the domain of concurrent object-oriented programming (COOP) there is a strong need for a formalism to describe concurrency. Such a formalism is ooered by Petri nets, which however lack thorough modularisation techniques for coping with models for large systems. An appropriate combination of COOP and Petri nets is required in order to proot from the strength of both methods. This paper gives an overview of ongoing research on PN-TOX, a paradigm and development environment for concurrent object-oriented programming based on Petri nets. First, we describe our object model. Each object has its own Petri net (encapsulated within the object) that models the concurrent behaviour of the object ; these objects are called Petri net objects. Cooperation and synchronisation of Petri net objects can be modelled by separate objects describing their cooperation scenarios. Our ideas concerning (single and multiple) inheritance, as part of the integration of Petri nets within the object-oriented paradigm, are presented. A set of formal net transformations serve as guidelines for behaviour-oriented inheritance of classes of Petri net objects. The PN-TOX environment is also (shortly) described. It supports the design, simulation, rapid pro-totyping and implementation of Petri net objects.