The sequence flow is the connector between two elements of the process. It represents a flow of execution. A sequence flow may optionally have a condition defined (conditional sequence flow). The engine always evaluates a task node's outgoing sequence flows: If the condition evaluates to true then the engine selects and follows that sequence flow; a sequence flow with no condition defined is always followed by the engine. A diamond shaped connector (see Appendix B, jBPM BPMN Constructs Reference, Gateways section for some pictorial examples) indicates a conditional sequence flow. Multiple sequence flows represent branching and merging without the usage of a gateway. Gateways, depending on their nature, handle conditional sequence flows in specific ways as we are about to see.

The following example process (see...