Connie's Convenience Store - About Peter Coad

54 Connie’s Convenience Store Establishing Responsibilities for Problem-Domain Objects
Establish responsibilities: “what I do.”
What’s the same? Just the basic services.
What’s different?
At some point, an authorized payment needs to be authorized. So you can think of
an authorized payment object as one that can authorize itself. Add a service called:
– authorize.
Add payment (and kinds of payment) responsibilities to the object model. Be sure
to include authorized payment, too (Figure 1–35):
Cash
cashTendered
Payment
amount
Check
Figure 1–35: Payments and kinds of payments: “what I know; who I know; what I do.”
Session
After all of that, a session will seem like a cakewalk.
It is.
Establish responsibilities: “what I know.”
What does a session object know?
The attributes are:
– start date
– start time
– end date
– end time.
1
bankRoutingNumber
accountNumber
amtTendered
n
AuthorizedPayment
authorizationCode
authorize
Sale
calcDiscount
Charge
cardNumber
cardType
expirationDate