BPMN2 — Formalizing the Source-Target relationships between Link Intermediate Event

Currently, there is no formalized way to relate Throw Link Events with their corresponding Catch Link Event(s). The spec briefly mentions that their names must be the same, but names are unreliable.

• There is no constraint on names, so I could create multiple Catch Link Events with the same name, thus breaking the model.
• Names are not used, in general throughout the spec, for formalizing relationships. Instead IDs are.
• Users do sometimes assign different names to the Throw and Catch (for example "A" for the throw and "from A" for the catch).

Recommendation: Add an explicit assocation from the Throw Link Event to the Catch Link Event

Add a new bidirectional association to the LinkEventDefinition.
(Updated+Link+Event+Metamodel.jpg)
If the LinkEventDefinition represents a 'throw' or 'source' link event, it will reference 1 LinkEventDefinitions representing the corresponding 'catch' or 'target' link event.
If the LinkEventDefinition represents a 'catch' or 'target' link event, it will reference 1 or more LinkEventDefinitions representing the corresponding 'throw' or 'source'
link events.
Spec updates:
(a) - Update Figure 10.70 to add new bidirectional association to the LinkEventDefinition class:
(Updated+Link+Event+Metamodel.jpg)

• Add two new associations to Table 10.91:
  (b) sources: Used to reference the corresponding 'catch' or 'target' LinkEventDefinitions, when this LinkEventDefinition represents a 'throw' or 'source'
  LinkEventDefinition.
  (c) target: Used to reference the corresponding 'throw' or 'source' LinkEventDefinition, when this LinkEventDefinition represents a 'catch' or 'target'
  LinkEventDefinition.
  Corresponding additions will be made to the BPMN XSD.
  Disposition: Resolved