UML Weekend Crash Course™ - To Parent Directory

76
Saturday Morning
Use Case dialog in the case study narrative
Next, you describe the dialog between the actor and the Use Case (see Table 7-5). You see
each action required by the actor and each response from the system. Some responses require
a choice based on the progress so far, so you see the decision statements included in the dialog.
This way, you know why the system gave the response it did. Other decision points are
the result of an action, like attempting to find the order using the Find Order Use Case.
Table 7-5
The Fill Order Use Case Narrative: Dialog
Field Name
Use Case dialog
Field Description
The system asks the user for an order number
The user provides the order number
The system asks for the order (from FindOrder Use Case).
If the Order is not found, Error, stop
Else:
The system provides the order to the user
The user chooses an item
Until the user indicates that he is done or there are no unfilled
item quantities greater than 0:
The system asks for the location of the item and
unfilled quantity (from the LocateProduct Use Case)
If the item is found (available):
The user indicates the quantity of the item filled
If there are any unfilled item quantities greater than 0:
Create a backorder (using the CreateBackorder Use Case)
Based on the Use Case dialog, see if you can find an error or something missing from the
Use Case diagram in Figure 7-1. Very often, taking a closer look at one aspect of the problem
(like the narrative) will reveal new insights to update existing diagrams. This is a normal and
desirable part of the modeling process.