BPMN Element Support Inventory

BPMN element support inventory

Flowable 8.0.0. Every verdict below was produced by generating a minimal BPMN process containing the element, deploying it to a running engine, and starting an instance — not by reading documentation. The fixtures are kept in the M4 branch as the tests the implementation stories are written against.

Written for #103. The scope is the 68 entries users are shown in SUPPORTED_BPMN_TYPES (14) and COMING_SOON_BPMN_TYPES (54) in WorkflowStudio.tsx. That list is Auton8's own inventory of what it offers, not a BPMN 2.0 conformance claim — see the M4 milestone description for what the specification defines and what is deliberately not claimed.

What the three verdicts mean

• executes — deployed, an instance started, and the token behaved as the element requires.
• deploys but does nothing — deploys cleanly, an instance starts, and the element has no effect. This is the dangerous category and the reason the epic exists.
• fails at deployment — the engine refuses it, with a message.

A limitation of this survey, stated plainly

A probe that deploys and starts an instance proves deployment and instantiation. It does not, on its own, prove the element's semantics. Complex Gateway is the proof: it deploys, an instance starts, and the token passes straight through to the next activity — no activation condition evaluated, no join. Flowable has no ComplexGatewayActivityBehavior and falls back to a default that simply proceeds.

Every element marked executes below was deployed and instantiated. Where an element's semantics were separately verified, the evidence column says so. The implementation stories are where per-element semantics get asserted; this page tells them which elements need that most.

Elements with no engine implementation at all — five

Element	Missing at which layer
bpmn:ComplexGateway	no activity behaviour (deploys, behaves as pass-through)
Intermediate Throw (Message)	no activity behaviour; validator rejects the definition
Compensation Start Event	no EventSubProcessCompensationStartEventActivityBehavior
Intermediate Throw (Link)	no link type in the BPMN model — deeper than a missing behaviour
Intermediate Catch (Link)	no link type in the BPMN model

The planning documents said three. Link events were found by this survey; spike #217 established that Flowable's BPMN model jar contains no link class at all, so the XML converter cannot represent one.

Already offered as supported (14)

Element	Verdict	Evidence
Start Event (None)	executes	deployed and started
Signal Start Event	executes	deployed and started
Timer Start Event	executes	deployed and started
Intermediate Catch (Timer)	executes	deployed and started
End Event (None)	executes	deployed and started
End Event (Terminate)	executes	deployed and started
Task (Generic)	executes	deployed and started
User Task	executes	deployed and started
Script Task	executes	deployed and started
Service Task (Behavior)	executes	deployed and started
Exclusive Gateway (XOR)	executes	deployed and started
Inclusive Gateway (OR)	executes	deployed and started
Parallel Gateway (AND)	executes	deployed and started
Sequence Flow	executes	deployed and started

Offered as "coming soon" (54)

Element	Verdict	Evidence
Message Start Event	executes	deployed and started
Conditional Start Event	fails at deployment	legal only inside an event subprocess, not at process level
Error Start Event	executes	deployed and started
Escalation Start Event	executes	deployed and started
Compensation Start Event	fails at deployment	no EventSubProcessCompensationStartEventActivityBehavior; descoped
Intermediate Throw (None)	executes	deployed and started
Intermediate Throw (Message)	fails at deployment	no behaviour class; validator rejects the definition
Intermediate Throw (Signal)	executes	deployed and started
Intermediate Throw (Escalation)	executes	deployed and started
Intermediate Throw (Link)	fails at deployment	no link type in the BPMN model at all (spike #217)
Intermediate Throw (Compensation)	executes	deployed and started
Intermediate Catch (Message)	executes	deployed and started
Intermediate Catch (Signal)	executes	deployed and started
Intermediate Catch (Conditional)	executes	deployed and started
Intermediate Catch (Link)	fails at deployment	no link type in the BPMN model at all (spike #217)
Message Boundary	executes	deployed and started
Timer Boundary	executes	deployed and started
Signal Boundary	executes	deployed and started
Conditional Boundary	executes	deployed and started
Error Boundary	executes	deployed and started
Escalation Boundary	executes	deployed and started
Cancel Boundary	executes	BoundaryCancelEventActivityBehavior ships; minimal transaction completed before the cancel applied
Compensation Boundary	executes	deployed and started
Message End	executes	deployed and started
Signal End	executes	deployed and started
Error End	executes	raw probe had no catching boundary; a modelling requirement, not an engine gap
Escalation End	executes	deployed and started
Cancel End	executes	CancelEndEventActivityBehavior ships; same fixture limitation
Compensation End	executes	deployed and started
Send Task	needs configuration	flowable-sendtask-invalid-implementation — needs a type/implementation attribute
Receive Task	executes	deployed and started
Manual Task	executes	deployed and started
Business Rule Task	needs configuration	NoClassDefFoundError org/kie/api — rules engine absent from the image (#105)
Call Activity	executes	first probe named a callee that did not exist; with a real callee, executes
Sub-Process (Embedded)	executes	deployed and started
Event Sub-Process	executes	deployed and started
Transaction	executes	deployed and started
Ad-Hoc Sub-Process	executes	deployed and started
Event-Based Gateway	executes	deployed and started
Complex Gateway	deploys but does nothing	no behaviour class; verified at runtime — token passes straight through, no activation condition, no join
Loop Marker	executes	deployed and started
Multi-Instance (Parallel)	executes	deployed and started
Multi-Instance (Sequential)	executes	deployed and started
Compensation Marker	executes	deployed and started
Pool / Participant	executes	deployed and started
Lane	executes	deployed and started
Message Flow	executes	deployed and started
Data Object Reference	executes	deployed and started
Data Store Reference	executes	deployed and started
Data Input	executes	deployed and started
Data Output	executes	deployed and started
Text Annotation	executes	deployed and started
Group	executes	deployed and started
Association	executes	deployed and started

Where the three internal lists disagree

Auton8 keeps three lists and they do not agree. Reconciling them is #107's job; this is the input.

1. Shown as "coming soon" but not in the runtime deny-lists — 22 items. These deploy today. Nothing stops them, and nothing promises they work: Message/Error/Escalation/Compensation/Conditional start events, Message/Signal/ Error/Escalation/Cancel/Compensation end events, all three activity markers plus the compensation marker, all four data elements, and all three artifacts.

2. In the runtime deny-lists but the engine runs them — 25 items. The deny-lists work at BPMN localName granularity — boundaryEvent, intermediateThrowEvent, subProcess — while the palette distinguishes variants. So denying boundaryEvent blocks all eight boundary variants even though Flowable runs seven of them, and denying intermediateCatchEvent blocks message, signal and conditional catches that all work.

This granularity mismatch is the substance of #107. One source of truth is not enough on its own: the source has to be keyed the way the palette is keyed, or the same coarse denial reappears.

3. collaboration is denied but maps to no palette entry — the palette offers Pool, Lane and Message Flow, not the collaboration container itself.

Diagram-only artifacts

bpmn:Group, bpmn:TextAnnotation and bpmn:Association are annotations in the specification. They deploy and are ignored by the engine, which is correct — they are not gaps. DataObjectReference and DataStoreReference are not in this category: they become typed process-variable declarations (#166).

Needs configuration rather than implementation

• Business Rule Task — NoClassDefFoundError: org/kie/api/runtime/rule/AgendaFilter. The rules engine is not in the image (#105).
• Send Task — flowable-sendtask-invalid-implementation; needs a type or implementation attribute.

A nuance the palette hides

Conditional Start Event fails at process level with "Unsupported event definition on start event", but the engine ships EventSubProcessConditionalStartEventActivityBehavior — it is legal only inside an event subprocess. The palette offers it as though it were a process start. Relevant to #158 and #162.