Package org.springframework.orm.jpa.vendor

Class EclipseLinkJpaDialect

java.lang.Object

org.springframework.orm.jpa.DefaultJpaDialect

org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect

All Implemented Interfaces:

Serializable, PersistenceExceptionTranslator, JpaDialect

public class EclipseLinkJpaDialect
extends DefaultJpaDialect

JpaDialect implementation for Eclipse Persistence Services (EclipseLink). Compatible with EclipseLink 3.0/4.0.

By default, this dialect acquires an early EclipseLink transaction with an early JDBC Connection for non-read-only transactions. This allows for mixing JDBC and JPA operations in the same transaction, with cross visibility of their impact. If this is not needed, set the "lazyDatabaseTransaction" flag to true or consistently declare all affected transactions as read-only. As of Spring 4.1.2, this will reliably avoid early JDBC Connection retrieval and therefore keep EclipseLink in shared cache mode.

NOTE: This dialect supports custom isolation levels with limitations. Consistent isolation level handling is only guaranteed when all Spring transaction definitions specify a concrete isolation level, and as of 6.0.10 also when using the default isolation level with non-readOnly and non-lazy transactions. See the "lazyDatabaseTransaction" javadoc for details.

Since:

2.5.2

Author:

Juergen Hoeller

See Also:

• setLazyDatabaseTransaction(boolean)
• LazyConnectionDataSourceProxy
• Serialized Form

Constructor Summary

Constructors

Constructor	Description
EclipseLinkJpaDialect()

Method Summary

Modifier and Type	Method	Description
Object	beginTransaction(EntityManager entityManager, TransactionDefinition definition)	This implementation invokes the standard JPA Transaction.begin method.
ConnectionHandle	getJdbcConnection(EntityManager entityManager, 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 resource transaction within a Spring-managed EclipseLink transaction.

Methods inherited from class org.springframework.orm.jpa.DefaultJpaDialect

cleanupTransaction, prepareTransaction, releaseJdbcConnection, translateExceptionIfPossible

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EclipseLinkJpaDialect

public EclipseLinkJpaDialect()

Method Details

setLazyDatabaseTransaction

public void setLazyDatabaseTransaction(boolean lazyDatabaseTransaction)

Set whether to lazily start a database resource transaction within a Spring-managed EclipseLink transaction.

By default, read-only transactions are started lazily but regular non-read-only transactions are started early. This allows for reusing the same JDBC Connection throughout an entire EclipseLink transaction, for enforced isolation and consistent visibility with JDBC access code working on the same DataSource.

Switch this flag to "true" to enforce a lazy database transaction begin even for non-read-only transactions, allowing access to EclipseLink's shared cache and following EclipseLink's connection mode configuration, assuming that isolation and visibility at the JDBC level are less important.

NOTE: Lazy database transactions are not guaranteed to work reliably in combination with custom isolation levels. Use read-only as well as this lazy flag with care. If other transactions use custom isolation levels, it is not recommended to use read-only and lazy transactions at all. Otherwise, you may see non-default isolation levels used during read-only or lazy access. If this is not acceptable, don't use read-only and lazy next to custom isolation levels in potentially concurrent transactions.

See Also:

• UnitOfWork.beginEarlyTransaction()
• TransactionDefinition.isReadOnly()
• TransactionDefinition.getIsolationLevel()

beginTransaction

@Nullable
public Object beginTransaction(EntityManager entityManager,
 TransactionDefinition definition)
                        throws PersistenceException,
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:

PersistenceException - if thrown by JPA methods

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(EntityManager entityManager,
 boolean readOnly)
                                   throws PersistenceException,
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:

entityManager - the current JPA EntityManager

readOnly - whether the Connection is only needed for read-only purposes

Returns:

a handle for the Connection, to be passed into releaseJdbcConnection, or null if no JDBC Connection can be retrieved

Throws:

PersistenceException - if thrown by JPA methods

SQLException - if thrown by JDBC methods

See Also:

• JpaDialect.releaseJdbcConnection(org.springframework.jdbc.datasource.ConnectionHandle, jakarta.persistence.EntityManager)
• ConnectionHandle.getConnection()
• SimpleConnectionHandle
• JpaTransactionManager.setDataSource(javax.sql.DataSource)