Spring Framework

org.springframework.orm.jpa.vendor
Class EclipseLinkJpaDialect

java.lang.Object
  extended by org.springframework.orm.jpa.DefaultJpaDialect
      extended by org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect
All Implemented Interfaces:
java.io.Serializable, PersistenceExceptionTranslator, JpaDialect

public class EclipseLinkJpaDialect
extends DefaultJpaDialect

JpaDialect implementation for Eclipse Persistence Services (EclipseLink). Developed and tested against EclipseLink 1.0 as well as 2.0-2.3.

By default, this class acquires a EclipseLink transaction to get the JDBC Connection early. This allows mixing JDBC and JPA/EclipseLink 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.

This class is very analogous to TopLinkJpaDialect, since EclipseLink is effectively the next generation of the TopLink product. Thanks to Mike Keith for the original EclipseLink support prototype!

Since:
2.5.2
Author:
Juergen Hoeller
See Also:
setLazyDatabaseTransaction(boolean), LazyConnectionDataSourceProxy, Serialized Form

Constructor Summary
EclipseLinkJpaDialect()
           
 
Method Summary
 java.lang.Object beginTransaction(javax.persistence.EntityManager entityManager, TransactionDefinition definition)
          This implementation invokes the standard JPA Transaction.begin method.
 ConnectionHandle getJdbcConnection(javax.persistence.EntityManager em, boolean readOnly)
          This implementation always returns null, indicating that no JDBC Connection can be provided.
protected  org.eclipse.persistence.sessions.Session getSession(javax.persistence.EntityManager em)
          Get a traditional EclipseLink Session from the given EntityManager.
 void setLazyDatabaseTransaction(boolean lazyDatabaseTransaction)
          Set whether to lazily start a database transaction within an EclipseLink transaction.
 
Methods inherited from class org.springframework.orm.jpa.DefaultJpaDialect
cleanupTransaction, getEntityManagerFactoryPlusOperations, getEntityManagerPlusOperations, prepareTransaction, releaseJdbcConnection, supportsEntityManagerFactoryPlusOperations, supportsEntityManagerPlusOperations, translateExceptionIfPossible
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

EclipseLinkJpaDialect

public EclipseLinkJpaDialect()
Method Detail

setLazyDatabaseTransaction

public void setLazyDatabaseTransaction(boolean lazyDatabaseTransaction)
Set whether to lazily start a database transaction within an EclipseLink 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 EclipseLink 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:
UnitOfWork.beginEarlyTransaction()

beginTransaction

public java.lang.Object beginTransaction(javax.persistence.EntityManager entityManager,
                                         TransactionDefinition definition)
                                  throws javax.persistence.PersistenceException,
                                         java.sql.SQLException,
                                         TransactionException
Description copied from class: DefaultJpaDialect
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.

Specified by:
beginTransaction in interface JpaDialect
Overrides:
beginTransaction in class DefaultJpaDialect
Parameters:
entityManager - the EntityManager to begin a JPA transaction on
definition - the Spring transaction definition that defines semantics
Returns:
an arbitrary object that holds transaction data, if any (to be passed into JpaDialect.cleanupTransaction(java.lang.Object)). May implement the SavepointManager interface.
Throws:
javax.persistence.PersistenceException - if thrown by JPA methods
java.sql.SQLException - if thrown by JDBC methods
TransactionException - in case of invalid arguments
See Also:
EntityTransaction.begin(), InvalidIsolationLevelException, DefaultJpaDialect.cleanupTransaction(java.lang.Object)

getJdbcConnection

public ConnectionHandle getJdbcConnection(javax.persistence.EntityManager em,
                                          boolean readOnly)
                                   throws javax.persistence.PersistenceException,
                                          java.sql.SQLException
Description copied from class: DefaultJpaDialect
This implementation always returns null, indicating that no JDBC Connection can be provided.

Specified by:
getJdbcConnection in interface JpaDialect
Overrides:
getJdbcConnection in class DefaultJpaDialect
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:
javax.persistence.PersistenceException - if thrown by JPA methods
java.sql.SQLException - if thrown by JDBC methods
See Also:
JpaDialect.releaseJdbcConnection(org.springframework.jdbc.datasource.ConnectionHandle, javax.persistence.EntityManager), ConnectionHandle.getConnection(), SimpleConnectionHandle, JpaTransactionManager.setDataSource(javax.sql.DataSource), NativeJdbcExtractor

getSession

protected org.eclipse.persistence.sessions.Session getSession(javax.persistence.EntityManager em)
Get a traditional EclipseLink Session from the given EntityManager.


Spring Framework