I have a sequence diagram for the following operation. The Activity class uses method present in ActivityBL class. The method is: GetActivities(ActivitySearch objt)

The result message is a collection of Activity objects. (Colletion in C#). How do we represent the return message in the sequence diagram? At present, I am listing it as message containing only one Activity object. How to represent it as a collection?

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  • 2
    List<Activity> or Activity[]
    – superM
    Commented Aug 24, 2012 at 10:31
  • @superM I could not find such a notation when I searched in google. Do you have reference to any credible/popular sites that shows this notation?
    – LCJ
    Commented Aug 24, 2012 at 10:44
  • I don't, but this is readable and even evident. No one will fail to understand this.
    – superM
    Commented Aug 24, 2012 at 10:48
  • 1
    I agree with @superM, this notation literally shows the return type. Just as Activity does. Commented Aug 24, 2012 at 10:53

1 Answer 1


You don't need to include the return value at all, unless it adds clarification about the turn of events in the diagram.

Since the message says "GetActivities" the return value and the fact that there is a return value is kinda obvious isn't it?

If you do include it I would keep it conceptual: "activities" or "activity list". For being more specific about types and data structures, if you must, I'd stick to putting it in a class diagram.

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