Using the Domain Model pattern - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 65

PlaceOrderService

updateDeliveryInfo ()
updateRestaurant ()
...

<< interface >>
PendingOrderRepository

<< interface >>
OrderRepository

create()
find()

findOrCreatePendingOrder()

<< interface >>
Restaurant Repository

findRestaurant()
findAvailableRestaurants()
...

Address

Address

Order

street1
city
state
...

updateDeliveryInfo()
updateRestaurant()
getTotal()
...

PendingOrder

Payment
Information

deliveryTime

updateDeliveryInfo ()
updateRestaurant()
getTotal()
...

Restaurant

Payment
Information

Name
serviceArea

<< interface >>
Coupon

opening hours

PendingOrder
LineItem

<< interface >>
Coupon

TimeRange

OrderLineItem

quantity

calculateDiscount()

MenuItem

get ExtendedPrice() quantity

name
price

getExtendedPric e ()

Figure 3.2 Domain model-based business logic for the Food to Go application

There are lots of details on this diagram, but let's focus on the important classes.
The key classes are as follows:
■ PlaceOrderService : Defines methods that correspond to steps of the Place
Order use case and update domain model objects.
■ PendingOrder : This application's shopping cart. PendingOrder has a delivery
time attribute and a delivery address, a collection of line items, an associ-
ated restaurant, and a coupon. Each line item has a quantity attribute and
an associated MenuItem .
■ Restaurant : Represents a restaurant that prepares food for delivery. A res-
taurant has a name attribute and one or more menu items available for
delivery, a geographic service area (which consists of a set of ZIP codes),
and opening hours.
■ MenuItem : Describes a menu item and has a name, a description, and a price.