Diff. btw. "iterative" and "stream"

[ocroquette]

Hi all

I am trying to find out exactly the difference between "iterative" and "stream" expansion regions on the activity diagrams.

This is my understanding:

• parallel: any number of any sub-activity can run at the same time (ie any item may enter the region at any time)
  
• stream: only a single instance of each sub-activity can run at the same time (ie an item can enter the region only if the the first activity to handle it is idle)
  
• iterative: only one single instance of a single sub-activity can run at the same time (ie. an item can enter the region only when the last item has left it)
  

Is this right?

Thanks!