Wrap up · 12 · 4 min
Cheat sheet and glossary
The rules worth memorising, and every term in one place.
Ten rules
- Sequence flow never crosses a pool boundary. Use message flow.
- Message flow never connects two elements in the same pool.
- A start event has no incoming sequence flow; an end event has no outgoing.
- Label activities verb + object.
- Label the exclusive gateway with the question and every outgoing flow with an answer.
- Split and join with the same gateway type unless you can explain why not.
- A parallel join waits. An exclusive join does not.
- Gateways do no work and take no time.
- Every path must reach an end event; no dangling flows.
- Model at the level your audience needs, and no further.
Glossary
| Term | Meaning |
|---|---|
| Token | Conceptual unit of execution. Created by a start event, consumed by an end event. |
| Pool | A participant. Contains exactly one process. |
| Lane | Subdivision of a pool by role. No execution semantics. |
| Collaboration | A diagram with two or more pools exchanging messages. |
| Sequence flow | Solid arrow. Execution order within one pool. |
| Message flow | Dashed arrow. Communication between pools. |
| Association | Dotted line linking an artifact to an element. No execution meaning. |
| Exclusive gateway | XOR. Exactly one outgoing path; join does not wait. |
| Parallel gateway | AND. All outgoing paths; join waits for all. |
| Inclusive gateway | OR. One or more paths; join waits for all that can still arrive. |
| Event-based gateway | Routes by whichever event occurs first. |
| Default flow | Backslash-marked outgoing flow taken when no condition is true. |
| Catching / throwing | Unfilled marker waits for a trigger; filled marker emits one. |
| Boundary event | Event attached to an activity's edge. Solid = interrupting, dashed = non-interrupting. |
| Terminate end event | Ends the whole instance immediately, destroying all remaining tokens. |
| Sub-process | Activity containing a process. Collapsed shows a plus. |
| Call activity | Thick-bordered activity invoking a reusable process defined elsewhere. |
| Event sub-process | Dotted-border sub-process triggered by an event, not by sequence flow. |
| Multi-instance | Activity executed once per item. Vertical bars = parallel, horizontal = sequential. |
| Data object | Information consumed or produced. Documentation, not control flow. |
| Black-box pool | Empty pool for a participant whose internals you do not model. |
| Conformance class | Defined BPMN subset: descriptive, analytic, common executable, full executable. |
| Deadlock | Tokens remain but no element can fire. Classically XOR split into AND join. |
Where to go next
- Model a process you actually run, descriptive level, then show it to someone who does the work. Their corrections are the lesson.
- Take any model and walk a token through it aloud. Every place you hesitate is an ambiguity in the model.
- Only then read the specification’s event and gateway tables; they make far more sense once the token rules are instinct.
After this module you can
- Look up any term used in the course