Execution logic

Execution of process instances is managed through state machines containing tokens running through respective state diagrams. The system state provides access to all state machines and tokens.

Upon instantiation of a process, a token is generated for the process instance. This token owns a state machine containing all token that may exist within the scope of the process. Moreover, a token at the unique start event of the process is created, and for all event-subprocesses, a token at the unique start event of the event-subprocess is created. Theses tokens flow through the process model and create all required child state machines and tokens running through these. The token flow logic depends on the node type and is described in below sections.

• Processes

• Activities

  • Subprocesses and ad-hoc subprocesses
  • Tasks

  Note

  Call activities are not supported.

• Gateways

  • Exclusive gateways
  • Parallel gateways
  • Event-based gateways

  Note

  Inclusive gateways and complex gateways are not supported.

• Events
  • Untyped start events
  • Typed start events
  • Boundary events
  • Intermediate catching events
  • Throwing events

Note

All tokens can be withdrawn at any time, e.g., when the respective state machine terminates.