UMLR — UML 2.1.2 Super: Execution Specification

The description for Execution Specification says:

“An ExecutionSpecification is a specification of the execution of a unit of behavior or action within the Lifeline. The

duration of an ExecutionSpecification is represented by two ExecutionOccurrenceSpecifications, the start

ExecutionOccurrenceSpecification and the finish ExecutionOccurrenceSpecification.”

This sounds right to me. However, the association ends ‘start’ and ‘finish’ are to the more general OccurrenceSpecification, thus:

“Associations

• start : OccurrenceSpecification[1]

References the OccurrenceSpecification that designates the start of the Action or Behavior.

• finish: OccurrenceSpecification[1]

References the OccurrenceSpecification that designates the finish of the Action or Behavior.”

The semantics also refer to OccurrenceSpecification.

“Semantics

The trace semantics of Interactions merely see an Execution as the trace <start, finish>. There may be occurrences

between these. Typically the start occurrence and the finish occurrence will represent OccurrenceSpecifications such as a

receive OccurrenceSpecification (of a Message) and the send OccurrenceSpecification (of a reply Message).”

The spec should make the description, association and semantics sections consistent.