Process modelling

We are going to describe the elements which define a jBPM process. A process is composed by:

• Nodes
• Transitions

To create a process definition in a graphical way, you can use jBPM Graphical Process Designer. This tool is packaged as a Eclipse plugin.

Nodes

The define the states of the process definition. They are connected by transitions. Both define the different path which can be followed in a running process definition. A running process definition is called process instance.

There are several types of nodes:

Start node

The start node defined the process entry point. Only one start node is permitted.

End node

End nodes define the end of the process execution. A process may have several end nodes. In this case the process finish when the process arrives to any of these end nodes.

Task node

A task node represents one or more tasks that are to be performed by humans.

Node node

You can define the behaviour using a Action element, which will be executed when the process arrives to the node.

State node

Decision node

There are 2 ways to model a decision. The distinction between the two is based on *who* is making the decision.

• When the decision is to be taken by the process, a decision node should be used.

• When the decision is taken by an external party, you should use multiple transitions leaving a state.

Fork node

A fork node splits one path of execution into multiple concurrent paths of execution.

Join node

The join node take all these concurrent executions before continue with the process execution.