Using the Domain Model pattern - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 88

The test case calls PendingOrder.updateDeliveryInfo() with valid delivery infor-
mation and verifies that it updates PendingOrder and returns true .
Implementing the method
Because PendingOrder already defines a stub method, this test compiles without a
problem. But in order for it to pass, we need to replace the stub with a real imple-
mentation that validates the delivery information and updates PendingOrder .
PendingOrder first checks that the delivery information is at least one hour in
the future by using the Java Calendar class. It then queries the database to validate
the delivery information. The simplest approach is to encapsulate this query within Res-
taurantRepository and define an isRestaurantAvailable() method. The update-
DeliveryInfo() method calls isRestaurantAvailable() and stores the delivery
information if it returns true :
public class PendingOrder {
private Date deliveryTime;
private Address deliveryAddress;
public boolean updateDeliveryInfo(
Address deliveryAddress,
Date deliveryTime) {
Calendar earliestDeliveryTime = Calendar.getInstance();
earliestDeliveryTime.add(Calendar.HOUR, 1);
if (deliveryTime.before(earliestDeliveryTime.getTime()))
bb return false;
b
bbbbbbb //How to access this?
bbbbbbb RestaurantRepository restaurantRepository = …;
if (restaurantRepository
.isRestaurantAvailable(deliveryAddress, deliveryTime)) {
this.deliveryAddress = deliveryAddress;
this.deliveryTime = deliveryTime;
return true;
} else
return false;
}
}
One important design issue, which we haven't resolved, is how PendingOrder
accesses RestaurantRepository . Let's look at how to do this.
Options for accessing a repository
Repositories are mainly used by the domain services, but they are also invoked by
some entities such as PendingOrder . To invoke a method on a repository object,