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General Board / Concept of "Is Return" message in sequence diagram

« on: April 01, 2009, 08:50:15 pm »

Hello everyone,

I have a problem to understand the concept of the checkbox "Is Return" of dialog "Message Property" on sequence diagrams.

In my opinion I should be able to select an operation from the called object as message if I check "Is Return". But I can only select an operation from the caller.

Another possibility would be that EA reverts the arrow if I select "Is Return".

But neither is the case.

Am I missing the point here?


In more detail:

- I have two Objects: A and B
- Object B has an operation: calculate(float, float): float
- I draw a message from A to B and select this operation as message
- EA shows the signature of this message.

Now I want to model the return value explicitly

- I draw a message from B to A
- and tick "Is Return".
  But I can't select an operation from Object B.
  So I would have to add the same operation to A
  in order to show the correct signature.
  But this is semantically wrong.
  A doesn't have this operation at all - it uses it.

or

- I draw a message from A to B
- and select the operation from B
- EA shows the correct signature -
  but the arrow points in the wrong direction
  and the complete diagram semantics is wrong now.