Author Topic: Control flow from initial to a merge node  (Read 1312 times)


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Control flow from initial to a merge node
« on: February 12, 2011, 01:11:29 am »
I have a simple activity diagram consisting of a serial control flow through Activities A, B and C. A decision box at the end can send the control flow back to Activity A. In line with UML2 ( To prevent activity A waiting for multiple inputs ), I've added a merge node above Activyty A.

All looks fine on paper but EA will not allow a control flow from an initial node to a merge. Does anyone know why? I assume its following UML rules but why ( in UML land ) is this not allowed. Seems a reasonable flow.

As a workaround I've added a dummy activity before the merge.  Can anyone justify why I've had to do this?

Found two workarounds to get the diagram as I wanted it. One sneaky and one SQL.
Beginning to think this is an EA qwirk, rather than a UML feature.
« Last Edit: February 12, 2011, 01:36:10 am by neilalbiston »


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Re: Control flow from initial to a merge node
« Reply #1 on: February 12, 2011, 03:44:12 am »

I will have to check the UML spec to see if this is "illegal", but here is how you can do the connection:

Rather than use the "quick linker", if you select the Control Flow from the Activity Diagram toolbox and then connect the Initial to the Merge it works just fine! (Select, move to the Initial Drag to the Merge)

This not the only anomoly on the Activity Diagram, the other is the Interupt Flow from an event within an Interruptable Region, you also have to select the Connector from the toolbox.


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