use case diagram one of cases one of the cases must be completed in order for the other to be completed

Question

I'm a little stuck on one question.In order for the ad to be "Premium", one of the three options must be selected. If none is selected, then the ad will be common. Can I somehow clarify this in this diagram, or is it acceptable in this form as it is ? (maybe I should point out other connections..?)

Answer 1

You can simply attach a constraint. That's a note element linked via a NoteLink (a dashed line) to the relevant UC bubble with containing text like { UC x must have been performed at least once }).

N.B. The bubble Specify... does not look like a use case but is rather a function (as part of the Place ad) and therefor not valid. UCs are just there to specify actor's goals and never any functions.

Answer 2

An easy solution: Don't use extend and include.

When analysing the use case you have to look at all the ways to achieve a goal. The goal is to place an ad. All the other "use cases" in your diagram are no meaningful goals. Maybe they could be intermediate goals, but they are not the reason for a case of using the system.

The result of the analysis can be captured in many ways. The use case diagram is not the right place for this. You could instead simply write up a main success scenario and then some alternative flows. Or, if you want to be more formal, you can use an activity diagram.