This transaction manager is appropriate for handling distributed transactions, i.e. transactions that span multiple resources, and for controlling transactions on application server resources (e.g. JDBC DataSources available in JNDI) in general. For a single JDBC DataSource, DataSourceTransactionManager is perfectly sufficient, and for accessing a single resource with Hibernate (including transactional cache), HibernateTransactionManager is appropriate, for example.
For typical JTA transactions (REQUIRED, SUPPORTS, MANDATORY, NEVER), a plain JtaTransactionManager definition is all you need, portable across all Java EE servers. This corresponds to the functionality of the JTA UserTransaction, for which Java EE specifies a standard JNDI name ("java:comp/UserTransaction"). There is no need to configure a server-specific TransactionManager lookup for this kind of JTA usage.
Transaction suspension (REQUIRES_NEW, NOT_SUPPORTED) is just available with a JTA TransactionManager being registered. Common TransactionManager locations are autodetected by JtaTransactionManager, provided that the "autodetectTransactionManager" flag is set to "true" (which it is by default).
Note: Support for the JTA TransactionManager interface is not required by Java EE. Almost all Java EE servers expose it, but do so as extension to EE. There might be some issues with compatibility, despite the TransactionManager interface being part of JTA. As a consequence, Spring provides various vendor-specific PlatformTransactionManagers, which are recommended to be used if appropriate: {@link WebLogicJtaTransactionManager}, {@link WebSphereUowTransactionManager} and {@link OC4JJtaTransactionManager}. For all other Java EE servers, the standard JtaTransactionManager is sufficient.
This pure JtaTransactionManager class supports timeouts but not per-transaction isolation levels. Custom subclasses may override the {@link #doJtaBegin} method forspecific JTA extensions in order to provide this functionality; Spring includes corresponding {@link WebLogicJtaTransactionManager} and {@link OC4JJtaTransactionManager}classes, for BEA's WebLogic Server and Oracle's OC4J, respectively. Such adapters for specific Java EE transaction coordinators may also expose transaction names for monitoring; with standard JTA, transaction names will simply be ignored.
Consider using Spring's tx:jta-transaction-manager configuration element for automatically picking the appropriate JTA platform transaction manager (automatically detecting WebLogic, WebSphere and OC4J).
JTA 1.1 adds the TransactionSynchronizationRegistry facility, as public Java EE 5 API in addition to the standard JTA UserTransaction handle. As of Spring 2.5, this JtaTransactionManager autodetects the TransactionSynchronizationRegistry and uses it for registering Spring-managed synchronizations when participating in an existing JTA transaction (e.g. controlled by EJB CMT). If no TransactionSynchronizationRegistry is available (or the JTA 1.1 API isn't available), then such synchronizations will be registered via the (non-EE) JTA TransactionManager handle.
This class is serializable. However, active synchronizations do not survive serialization. @author Juergen Hoeller @since 24.03.2003 @see javax.transaction.UserTransaction @see javax.transaction.TransactionManager @see javax.transaction.TransactionSynchronizationRegistry @see #setUserTransactionName @see #setUserTransaction @see #setTransactionManagerName @see #setTransactionManager @see WebLogicJtaTransactionManager
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