public class

TopLinkJpaDialect

extends DefaultJpaDialect
java.lang.Object
   ↳ org.springframework.orm.jpa.DefaultJpaDialect
     ↳ org.springframework.orm.jpa.vendor.TopLinkJpaDialect

Class Overview

JpaDialect implementation for Oracle TopLink Essentials. Developed and tested against TopLink Essentials v2.

By default, this class acquires a TopLink transaction to get the JDBC Connection early. This allows mixing JDBC and JPA/TopLink operations in the same transaction. In some cases, this eager acquisition of a transaction/connection may impact scalability. In that case, set the "lazyDatabaseTransaction" flag to true if you do not require mixing JDBC and JPA operations in the same transaction. Otherwise, use a LazyConnectionDataSourceProxy to ensure that the cost of connection acquisition is near zero until code actually needs a JDBC Connection.

See Also

Summary

Public Constructors
TopLinkJpaDialect()
Public Methods
Object beginTransaction(EntityManager entityManager, TransactionDefinition definition)
This implementation invokes the standard JPA Transaction.begin method.
ConnectionHandle getJdbcConnection(EntityManager em, boolean readOnly)
This implementation always returns null, indicating that no JDBC Connection can be provided.
void setLazyDatabaseTransaction(boolean lazyDatabaseTransaction)
Set whether to lazily start a database transaction within a TopLink transaction.
Protected Methods
Session getSession(EntityManager em)
Get a traditional TopLink Session from the given EntityManager.
[Expand]
Inherited Methods
From class org.springframework.orm.jpa.DefaultJpaDialect
From class java.lang.Object
From interface org.springframework.dao.support.PersistenceExceptionTranslator
From interface org.springframework.orm.jpa.JpaDialect

Public Constructors

public TopLinkJpaDialect ()

Public Methods

public Object beginTransaction (EntityManager entityManager, TransactionDefinition definition)

This implementation invokes the standard JPA Transaction.begin method. Throws an InvalidIsolationLevelException if a non-default isolation level is set.

This implementation does not return any transaction data Object, since there is no state to be kept for a standard JPA transaction. Hence, subclasses do not have to care about the return value (null) of this implementation and are free to return their own transaction data Object.

Parameters
entityManager the EntityManager to begin a JPA transaction on
definition the Spring transaction definition that defines semantics
Returns
Throws
PersistenceException
SQLException
TransactionException

public ConnectionHandle getJdbcConnection (EntityManager em, boolean readOnly)

This implementation always returns null, indicating that no JDBC Connection can be provided.

Parameters
em the current JPA EntityManager
readOnly whether the Connection is only needed for read-only purposes
Returns
  • a handle for the JDBC Connection, to be passed into releaseJdbcConnection, or null if no JDBC Connection can be retrieved
Throws
PersistenceException
SQLException

public void setLazyDatabaseTransaction (boolean lazyDatabaseTransaction)

Set whether to lazily start a database transaction within a TopLink transaction.

By default, database transactions are started early. This allows for reusing the same JDBC Connection throughout an entire transaction, including read operations, and also for exposing TopLink transactions to JDBC access code (working on the same DataSource).

It is only recommended to switch this flag to "true" when no JDBC access code is involved in any of the transactions, and when it is acceptable to perform read operations outside of the transactional JDBC Connection.

See Also
  • oracle.toplink.sessions.UnitOfWork#beginEarlyTransaction()

Protected Methods

protected Session getSession (EntityManager em)

Get a traditional TopLink Session from the given EntityManager.