In the last few years, business process management systems have been employed for handling information
systems of ever increasing complexity. As a consequence, the adoption of modelling languages
enabling smooth and seamless transitions among the various phases of the process lifecycle, the ability
of exploiting coordination schema over distributed execution contexts and the support for dynamic evolution
and reconfiguration have become software engineering issues of great importance. This paper proposes
the use of PN-Engine, a decentralized Petri nets execution engine, as a business process enactment
engine. PN-Engine, which is based on the Jini service architecture, supports the decentralized execution of
process models specified as Petri nets (PNs) enhanced with modular constructs and offers suitable mechanisms
for dealing with the aforementioned design issues. PN-Engine allows to deploy and enact a new
version of an existing process model without requiring the stopping/removal of older instances that
are still running. The paper presents a novel approach enabling a decentralized migration procedure
where concurrent portions of older instances migrate asynchronously to the new process model. Advantages
of the proposed approach are demonstrated by means of an example concerning a workflow for a
wine-production process.
