UML22 — Interactions model sequences of events

Interactions model sequences of events. The metaclass EventOccurrence represents the occurrence of an event. Currently, there are the following kinds of events known: i. sending of a message ii. receiving of a message iii. start of the execution of a behavior iv. finish of the execution of a behavior v. stop First, clearly, there could be many more events that one might want to represent on a lifeline. In particular, the invocation of an action is a possible event, and should be allowed to be represented. Secondly, event occurrence is modeled poorly. It is shown as a kind of message end, which means that every event occurrence inherits the notion of being a message end point, even if the event has nothing to do with a message (such as a stop event). Clearly the inheritance hierarchy is inverted. A message end can represent an event occurrence (such as the sending or receiving of a message). But not every event occurrence is a message event.

Discussion: This was fixed in UML 2.1 Revised Text: N/A Disposition: Closed, no change