alt fragments with a mind of their own.

[ChrisBD]

I've been tasked to look at problems that one user here is having.
They have a sequence diagram with 3 alt fragments on it.
Our models reside on a MySQL DB. They are under VC and the files are checked out to this person.
Apparantly everytime he restarts EA and loads his work the alt frames have wandered.
I note that this was a bug that was allegedly fixed back in 2008. Were using 7.5.
Is there something that I'm missing?

[ChrisBD]

Okay I have looked further into this.
It would appear that what is happening is that the user is dragging an item from another package on to the sequence diagram and selecting the default option of "Simple link" in order to create a lifeline.

When a Fragment (alt, par etc) is used and the diagram is saved; EA is closed and reopened; the Fragment moves.

If the lifleine was created by selecting "As Instance of Element (Object)" then the problem does not occur.

On looking further it appears almost as if EA doesn't know how to draw a lifeline object unless it is an instance. There is a reference to the element object within the XMI file if I export the model, but no positional data - how EA manages to display this in the first place I do not know!

Is this expected behaviour?

Should EA insist on using an instance, or should it handle the use of Simple references in this case by storing the positional data, that it evidentally produces in order to display the diagram in the first place?

[Geert Bellekens]

Chris,

To me this is a plain and simple bug.
It might be a "best practice" to use instances rather then classifiers in the sequence diagrams, but no matter which is used, the fragments should stay put.

Geert

[ChrisBD]

Thanks for the quick response Geert.

I've posted a bug report on this issue, so it remains to see what happens.

My gut feeling is that it revolves around the order in which packages are loaded into EA, and so even though the use of instances is "best practice" Sparx wont be able to fix it, just remove the "add as a simple link" behaviour.

In the meantime I'll suggest to people that they use instances as a work around.

I'm wondering whether this issue is related to another that we have, where a user has been having items disappear from his diagrams. I haven't looked at that as yet, but if they are "linked" rather than "instanced" from other packages then that would explain a lot.