Encapsulating the business logic with a POJO façade - POJOs in Action: Developing Enterprise Applications with Lightweight Frameworks - page 260

<<interface>>
Platform
Transaction
Manager

Transaction
Interceptor

Uses

getTransaction()
commit()
rollback()

invoke()

Hibernate
Transaction
Manager

JdoTransaction
Manager

JtaTransaction
Manager

...

Manages local
transactions

Manages global/JTA
transactions

Figure 7.2 The different implementations of the PlatformTransactionManager interface

Using local transactions
A local transaction involves only a single database, and can be started, committed,
and rolled back using the JDBC or persistence framework API s directly. Spring
provides several PlatformTransactionManager implementations for managing
local transactions; which one you use depends on how the application accesses
the database. A JDO application uses a JdoTransactionManager , which manages
transactions using the JDO Transaction interface, and a Hibernate application
uses a HibernateTransactionManager , which manages transactions using the
Hibernate Transaction interface. In addition, a JDBC application uses a Data-
SourceTransactionManager , which manages transactions using the JDBC Connec-
tion interface (this is described in more detail in chapter 9).
As well as managing transactions, these PlatformTransactionManager imple-
mentations manage a connection that can be used by the repositories that are
called during the transaction. Behind the scenes, they use a ThreadLocal to bind
the connection to the thread. Before starting the transaction, the JdoTransaction-
Manager opens a PersistenceManager , which can be obtained by the repositories
using PersistenceManagerFactoryUtils.getPersistenceManager() . It closes the
PersistenceManager after the transaction ends. Similarly, a HibernateTransaction-
Manager manages a Session , which the repositories can access by calling Session-
FactoryUtils.getSession() . Spring's ORM template classes use these methods to
get a persistence framework connection.