A flow is a representation of a particular route through a business process or business operation. The flow reflects the results of performing different actions and responding to system-generated events within the business process. The Automaton is a state machine-based mechanism that the toolkit uses to handle the various flows that can occur within a business process or presentation sequence. The Automaton is particularly useful for complex flows that have many branches with compound and complex conditions. These complex flows often, for example, occur with HTML client-based applications. A flow processor is the implementation of the Automaton for a particular process.

The Automaton is based on the concepts and terminology developed for UML statechart diagrams. A statechart diagram shows the lifecycle of an object (in this case a flow) as a sequence of states. Events trigger the transitions between states, and the action can be contingent on a complex set of conditions. The abstraction of the conditions into a single entity constitutes a guard condition. If the result of an event passes the tests of the guard condition, the object moves into the next state in its lifecycle. For more information on the terminology used in statechart diagrams, see the UML specification.