Originally posted by Zhou Can:
How to cancel the action of booking by pressing the "Cancel" button ? Is only interrupting the booking thread enough?
I am afraid only canceling is not enough. You have to know where the thread is at, if a ticket has been deducted, then 'cancel' is supposed to credit it back.
In my design, at each step along the way, there is 'go forward' and 'go backward' buttons. And of course, you can always click 'X' at upper right corner of the window to cancel the whole thing.
Once a customer has booked the ticket, there is no way to cancel it, which is not part of the requirement. However, I think you can define a kind of booking operation, which deduct -1 from the total number of ticket. So that will equal to increasing ticket number by 1.