Skipping steps in a use case alternate flow

[inad]

Just trying to gather thoughts and opinions on how folks handle this.

So I have this alternate path in a use case of mine. It happens to be identical to the main flow except that a couple of steps are skipped. I would be inclined to write a simple alternate path such as:

At {Extension Point} if {condition}

1.- The flow of events proceeds exactly as in the basic path except that steps x and y are skipped.

Is this common practice. Are there alternative/better ways of handling this ?

[qwerty]

I think that if the desciption can be understood it is okay. In that case, well yes. I as a reader can understand what you mean. You should add a step 2. "The use case ends" to make that clear.

q.

[Robert Sheridan]

Thanks, before I started using stuctured scenarios I wrote alternates with 'omit steps x and y' and was wondering how to do it in structured scenarios.  It wont generate a activity diagram automatically but that is a small price to pay.

[RoyC]

(Extrapolating from the letters of your steps) wouldn't you make your alternative path take effect at step w of the main flow and say "if {condition} then step out and rejoin Main at step z"?

[Doug Blake]

I would say that in general, we have a lazy streak (not a criticism) so its easy to say 'same x but leave out y'.

I would copy the original and delete the steps so I have a complete standalone description of the scenario with no references to other scenarios.

[Robert Sheridan]

I have been on projects where all the steps from the Normal were replicated and in my view it creates 2 challenges:
1. It makes the use case less concise to read (though also less ambiguous) and I have found that large docs => poorer reviews
2. If the main flow changes you have to replicate the changes to all the other flows (I know, I am basically lazy)

[Paolo F Cantoni]

I would say that in general, we have a lazy streak (not a criticism) so its easy to say 'same x but leave out y'.

I would copy the original and delete the steps so I have a complete standalone description of the scenario with no references to other scenarios.

It's more than it just being a "lazy streak".  Engineers are inherently lazy people (why do I need to do this repetitive thing?).

Its also the tension between declarative and prescriptive specifications.

"Same as X but leave out Y" is a declarative form.

I'm all for declarative forms whenever possible, because they embody a greater truth.  The problem is how to generate the implementation (which currently needs to be prescriptive) from the declarative form.

Paolo