Java Reference
In-Depth Information
7.5 Implementing a result factory
The third step in the process of implementing a POJO façade is writing the result
factory that is called by the POJO façade to detach the domain objects that it
returns to the presentation tier. In a JDO application, the result factory must call
the JDO detachment API s, which return detached copies of the persistent objects.
In a Hibernate application, the result factory simply has to make sure the
required objects are loaded because detachment is automatic. In both cases, the
POJO façade must make sure that the object graph contains all of the objects
required by the presentation tier.
The set of objects that need to be detached is primarily determined by the data
that is displayed by the presentation tier. For example, in the Place Order use case,
the Order page displays data from several objects, including the delivery information
from the PendingOrder , the quantities from the pending order's line items, and the
menu items from the selected restaurant. Consequently, the PlaceOrderFacade must
return an object graph containing the PendingOrder , its line items, its restaurant, and
its restaurant's menu items. Figure 7.7 shows the object graph starting from the
PendingOrder that needs to be returned to the presentation tier.
:Pending
Order
:Coupon
:OpeningHours
:PendingOrder
Lineitem
:Restaurant
:ServiceArea
:MenuItem
Figure 7.7
The object graph reachable from PendingOrder
 
 
Search WWH ::




Custom Search