CODEWITHSUNDEEP
umluse-case
Xerath
Xerath

Reputation: 1099

UML sequence diagram - Diagram without actors?

I have a scene where I want to show the exception case in a sequence diagram. In my case, this sequence diagram pretty much shows the interactions between objects (classes) than between actor and object. So, is it ok to have sequence diagram without actors ?

Upvotes: 1

Views: 3694

Answers (1)

Gangnus
Gangnus

Reputation: 24484

It is absolutely OK.

  1. Actors are one of the main elements in UC diagrams, but not in sequence diagrams. A sequence diagram without messages and lifelines - that one is really hard to imagine. These are the essence of the SD. And actor merely can be used there, if the sequence is about interaction between some border component and an external object (actor).

  2. But even if they were extremally important, you needn't use every element of the main set of elements of a diagram. For example, a use case diagram that contains many use cases and some additional elements from other diagrams can be drawn without actors - for better understanding.

But if you are merely training to use UML diagrams, draw some sequence diagram with actor or two - you should learn how to use them, too.

Upvotes: 1

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