Using an exposed domain model - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 305

A Spring PlatformTransactionManager , which manages transactions using
the JDO or Hibernate transaction API

■

A TransactionRetryInterceptor , which is a custom Spring AOP interceptor
that automatically retries a transaction if a database concurrency error
occurs

■

The domain model-based business logic

■

As you can see, Spring implements the majority of the transaction and connection
management logic, including the TransactionInterceptor and the servlet filter
for managing persistence framework connections. The only custom infrastructure
code is the TransactionRetryInterceptor .
Let's look at the details. Each servlet handles a request by first invoking the
PlaceOrderService and calling other domain model classes, such as repositories,
to get the data to display. It then forwards the request to a JSP page, which it

Servlet JSP Page

Spring

OpenPersistence
Manager
InViewFilter

OpenSession
InViewFilter

Transaction
Interceptor

Transaction
Retry
Interceptor

Hibernate/JDO
Transaction
Manager

Domain

Persistence Framework

PlaceOrderService

Connection
Factory

Transaction

Connection updateDeliveryInfo()

updateRestaurant()
...

begin()
commit () Connection open() close()

Pending
Order

Restaurant

PendingOrder
Repository

Restaurant
Repository

Figure 8.8 Exposed business logic for the Place Order use case