Implementing dynamic paged queries - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 438

This example calls ScrollableResults.scroll() to skip over the first 100 rows
and ScrollableResults . next() to move through the orders. You need to write
more code when using Criteria.scroll() than you do when using list() , but it
is a more efficient way to execute some queries.
At this point you've had an overview of the challenges of implementing effi-
cient dynamic paged queries in a Hibernate or JDO application. Next, let's take an
in-depth look at using JDO .

11.4 A JDO design example

In a JDO application, queries are typically executed by the domain model's reposi-
tories. This means that the code that implements a search screen will ultimately call
a repository, which must generate a query and call JDO to execute it. Figure 11.5
shows the JDO version of the OrderRepository , which is responsible for retrieving
orders from the database.It defines a findOrders() method whose signature is sim-
ilar to the OrderDAO method we saw earlier. The startingIndex and pageSize

<<interface>>
OrderRepository

PagedQuery
Result

PagedQueryResult findOrders(startingIndex, pageSize, OrderSearchCriteria)
...

more

JDO
OrderRepository
Impl

Order

JDOFindOrders
Callback

Spring

JdoTemplate

<<interface>>
JdoCallback

execute(JdoTemplate)

Figure 11.5 The JDO version of the design for finding orders