Fork or Infinity

[incipiens]

I do not understand the difference of the fork sign and the infinity sign, both of them are structured Activities?

[jeshaw2]

Lets get the terminology figured out first.  In an activity diagram a fork designates a split in the flow of activities, which seems out of context with the structured activity adornment of the infinity symbol.  I think you are referring to the rake adornment which looks like a fork, but appears within the activity element as does the infinity symbol.  

The rake indicates that the activity is a CALLBEHAVIORACTION which is a call to behavior outside of the scope of the current activity.

The infinity symbol designates the current activity to be structured, having more finely grained activities within it.

Hope this helps,
Jim

[Paolo F Cantoni]

I do not understand the difference of the fork sign and the infinity sign, both of them are structured Activities?

It's NOT an infinity symbol!  It's a set of chain links indicating there is a linked diagram.

Paolo

[jeshaw2]

Could not find the chain link in the UML 2.1 specification, but I did find it in the EA help file as designating a sturctured activity (a composite activity having a link to a child activity).  The UML notation makes use of the <<structured>> notation instead.  Is this an EA specific notation?