In the current iteration we are considering various scenarios and system events such as:
Process Sale: makeNewSale, enterItem, endSale, makePayment
If collaboration diagrams are used to illustrate the use-case realizations, a different collaboration diagram will be required to show the handling of each system event message. For example (Figure 17.1):
On the other hand, if sequence diagrams are used, it may be possible to fit all system event messages on the same diagram, as in Figure 17.2.