The ePNK: An Extensible Petri Net Tool for PNML

The Petri Net Markup Language (PNML) is an XML-based interchange format for all kinds of Petri nets, which is an ISO/IEC International Standard 15909-2 now. The focus of this standard is on PNML as an interchange format for high-level Petri nets. PNML, however, is more general and allows exchanging all kinds of Petri nets.

To this end, PNML introduced the concept of Petri Net Type Definitions. There are many tools supporting one form of PNML or another. In particular, there is the PNML Framework, which helps tool developers implementing an interface to PNML by providing a framework and an API for loading and saving Petri net documents in PNML.

This framework is based on the Eclipse Modeling Framework and has the focus on the underlying meta-models of Petri nets. The PNML Framework, however, is not generic in the following sense: Whenever a new Petri net type is created, the code for the complete tool needs to be regenerated. Moreover, the PNML Framework does not come with a graphical editor.

The ePNK overcomes these limitations: It provides an extension-point so that new Petri net types can be plugged into the ePNK without touching the code of the ePNK. For defining a new Petri net type, the developer, basically, needs to give a class diagram defining the concepts of the new Petri net type, along with a mapping of these concepts to XML syntax.

This type can then be plugged into the ePNK, and its graphical editor will be able to edit nets of this new type with all its features. This paper present the main idea of the ePNK, and how to use and extend it.