Actor "lifeline" in sequence diagram

[qwerty]

I noticed that when using an Actor from the toolbox the diagram does not show the classifier but only the object name (and there without leading colon). Is that only for my installation or could someone confirm that behavior? If so I'll submit a bug report.

q.

[Rayner]

It is actually the opposite:
When creating an Actor using the toolbox you are actually defining a Classifier.

To create a instance:
Right-click the actor, Advanced, Convert to Instance

However, if you want the model to be UML compliant then you must contain this instance (actually a property) within a classifier.

[qwerty]

Thanks Rayner,
I actually reported it as a bug. In their manual they say explicitly that sequence diagrams MUST contain just objects (seehttp://www.sparxsystems.com/enterprise_architect_user_guide/9.2/standard_uml_models/sequence_diagrams_and_version_.html and especially the actor left in the diagram there) and here they create a classifier? No good! It must be an object like the lifeline element (and supposed to show as actor and not as rectangle).

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[Rayner]

Actually, the guideline is wrong in stating that a sequence diagram MUST contain just objects.

The UML specification states that a Lifeline is a generalization of NamedElement. Meaning that it can be practically anything in UML (both a Classifier or some kind of extension of Property).

It is therefore OK to have Actor as a Lifeline since an Actor is a generalization of Classifier.

The EA implementation of Lifeline isn't that bad. One could imagine constricting edits so that you may not create instances when the parent itself is not a Classifier, but as I have come to understand; EA does not constrict the user much w.r.t. the UML standard.

[qwerty]

Actually, the guideline is wrong in stating that a sequence diagram MUST contain just objects.

In terms of UML/OMG it is wrong. But it is a constrained which comes from their implementation of the tool. When you look at what a sequence diagram tells you then it is most clear that it shows a life behaviour. And this can only be executed by objects. So I'd rather say OMG is wrong in not explicitly stating that objects must be used. YMMV.

q.