Statebox

Statebox is the first truly Open Source business process management (BPM) and workflow software designed for all types of organizations. Statebox is a user-friendly application to manage workflow efficiently and effectively. Business users and process experts with no programming experience can design and run workflows, increase transparency, and radically reduce paperwork. Automate processes across systems, including human resources, finance, and operations.

Statebox is a workflow engine written in Java. The engine is very fast and lightweight, without sacrificing functionality. Its main strengths are the very expressive Petri net based notation it uses to define workflows and the powerful resource selection mechanisms it provides.

Petri Nets and Workflow

Petri nets are a tool for modeling and analyzing dynamic processes. A Petri net is composed by places and transitions and has a standard graphical representation where places are circles and transitions are squares. Places and transitions are connected by directed edges, forming a directed bipartite graph, that is, following the direction of an edge it is only possible to go from a place to a transition or from a transition to a place. Figure 1 shows the graphical representation of a simple Petri net.

Figure 1. A simple Petri net.

Places and transitions represent the static aspect of a Petri net, the dynamic aspect is represented by tokens. A token is a mark that can only be in places and that changes places according to the firing of the transitions. In classical Petri nets, when a transition fires it consumes exactly one token for each input (places with edges going to the transition) and produces exactly one token for each output (places with edges coming from the transition).