Modelling Local and Global Behaviour: Petri Nets and Event Coordination

Today, it is possible to generate major parts of a software system from models. Most of the generated code, however, concerns the structural parts of the software; the parts that concern the functionality or behaviour of a system are still programmed manually. In order to overcome this problem, we are developing the concept of coordination diagrams that define the global behaviour on top of structural software models. Basically, these diagrams define how the local behaviour of an element is coordinated with the behaviour of the elements it is connected to. The exact concepts of these coordination diagrams and their notation is still under development, but there exists a first prototype for experimenting and for fine-tuning its features. We call it the Event Coordination Notation (ECNO). For experimenting with the ECNO, we implemented also a simple modelling notation for the local behaviour, which is based on Petri nets. In this paper, we briefly discuss the general idea of the ECNO and then present ECNO nets that define the local behaviour of elements. They are implemented as a Petri net type for the ePNK tool, together with a code generator that produces code that can be used in the ECNO framework and runtime environment. This way, all the behaviour of a system can be modelled – and code can be generated that easily integrates with the structural models and existing software.