https://github.com/spring-projects/spring-framework: Spring Object/Relational Mapping (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.orm.hibernate5;

import java.sql.Connection;
import java.sql.ResultSet;
import javax.persistence.PersistenceException;
import javax.sql.DataSource;

import org.hibernate.ConnectionReleaseMode;
import org.hibernate.FlushMode;
import org.hibernate.HibernateException;
import org.hibernate.Interceptor;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.resource.transaction.spi.TransactionStatus;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.jdbc.datasource.ConnectionHolder;
import org.springframework.jdbc.datasource.DataSourceUtils;
import org.springframework.jdbc.datasource.JdbcTransactionObjectSupport;
import org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy;
import org.springframework.lang.Nullable;
import org.springframework.transaction.CannotCreateTransactionException;
import org.springframework.transaction.IllegalTransactionStateException;
import org.springframework.transaction.InvalidIsolationLevelException;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionSystemException;
import org.springframework.transaction.support.AbstractPlatformTransactionManager;
import org.springframework.transaction.support.DefaultTransactionStatus;
import org.springframework.transaction.support.ResourceTransactionManager;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.util.Assert;


PlatformTransactionManager implementation for a single Hibernate SessionFactory. Binds a Hibernate Session from the specified factory to the thread, potentially allowing for one thread-bound Session per factory. SessionFactory.getCurrentSession() is required for Hibernate access code that needs to support this transaction handling mechanism, with the SessionFactory being configured with SpringSessionContext. 
Supports custom isolation levels, and timeouts that get applied as
Hibernate transaction timeouts.

This transaction manager is appropriate for applications that use a single Hibernate SessionFactory for transactional data access, but it also supports direct DataSource access within a transaction (i.e. plain JDBC code working with the same DataSource). This allows for mixing services which access Hibernate and services which use plain JDBC (without being aware of Hibernate)! Application code needs to stick to the same simple Connection lookup pattern as with DataSourceTransactionManager (i.e. DataSourceUtils.getConnection or going through a TransactionAwareDataSourceProxy). 
Note: To be able to register a DataSource's Connection for plain JDBC code, this instance needs to be aware of the DataSource (setDataSource). The given DataSource should obviously match the one used by the given SessionFactory. 
JTA (usually through JtaTransactionManager) is necessary for accessing multiple transactional resources within the same transaction. The DataSource that Hibernate uses needs to be JTA-enabled in such a scenario (see container setup). 
This transaction manager supports nested transactions via JDBC 3.0 Savepoints. The AbstractPlatformTransactionManager.setNestedTransactionAllowed "nestedTransactionAllowed"} flag defaults to "false", though, as nested transactions will just apply to the JDBC Connection, not to the Hibernate Session and its cached entity objects and related context. You can manually set the flag to "true" if you want to use nested transactions for JDBC access code which participates in Hibernate transactions (provided that your JDBC driver supports Savepoints). Note that Hibernate itself does not
support nested transactions! Hence, do not expect Hibernate access code to
semantically participate in a nested transaction.

Author:Juergen Hoeller
See Also:
Since:4.2
/**
 * {@link org.springframework.transaction.PlatformTransactionManager}
 * implementation for a single Hibernate {@link SessionFactory}.
 * Binds a Hibernate Session from the specified factory to the thread,
 * potentially allowing for one thread-bound Session per factory.
 * {@code SessionFactory.getCurrentSession()} is required for Hibernate
 * access code that needs to support this transaction handling mechanism,
 * with the SessionFactory being configured with {@link SpringSessionContext}.
 *
 * <p>Supports custom isolation levels, and timeouts that get applied as
 * Hibernate transaction timeouts.
 *
 * <p>This transaction manager is appropriate for applications that use a single
 * Hibernate SessionFactory for transactional data access, but it also supports
 * direct DataSource access within a transaction (i.e. plain JDBC code working
 * with the same DataSource). This allows for mixing services which access Hibernate
 * and services which use plain JDBC (without being aware of Hibernate)!
 * Application code needs to stick to the same simple Connection lookup pattern as
 * with {@link org.springframework.jdbc.datasource.DataSourceTransactionManager}
 * (i.e. {@link org.springframework.jdbc.datasource.DataSourceUtils#getConnection}
 * or going through a
 * {@link org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy}).
 *
 * <p>Note: To be able to register a DataSource's Connection for plain JDBC code,
 * this instance needs to be aware of the DataSource ({@link #setDataSource}).
 * The given DataSource should obviously match the one used by the given SessionFactory.
 *
 * <p>JTA (usually through {@link org.springframework.transaction.jta.JtaTransactionManager})
 * is necessary for accessing multiple transactional resources within the same
 * transaction. The DataSource that Hibernate uses needs to be JTA-enabled in
 * such a scenario (see container setup).
 *
 * <p>This transaction manager supports nested transactions via JDBC 3.0 Savepoints.
 * The {@link #setNestedTransactionAllowed} "nestedTransactionAllowed"} flag defaults
 * to "false", though, as nested transactions will just apply to the JDBC Connection,
 * not to the Hibernate Session and its cached entity objects and related context.
 * You can manually set the flag to "true" if you want to use nested transactions
 * for JDBC access code which participates in Hibernate transactions (provided that
 * your JDBC driver supports Savepoints). <i>Note that Hibernate itself does not
 * support nested transactions! Hence, do not expect Hibernate access code to
 * semantically participate in a nested transaction.</i>
 *
 * @author Juergen Hoeller
 * @since 4.2
 * @see #setSessionFactory
 * @see #setDataSource
 * @see SessionFactory#getCurrentSession()
 * @see DataSourceUtils#getConnection
 * @see DataSourceUtils#releaseConnection
 * @see org.springframework.jdbc.core.JdbcTemplate
 * @see org.springframework.jdbc.datasource.DataSourceTransactionManager
 * @see org.springframework.transaction.jta.JtaTransactionManager
 */
@SuppressWarnings("serial")
public class HibernateTransactionManager extends AbstractPlatformTransactionManager
		implements ResourceTransactionManager, BeanFactoryAware, InitializingBean {

	@Nullable
	private SessionFactory sessionFactory;

	@Nullable
	private DataSource dataSource;

	private boolean autodetectDataSource = true;

	private boolean prepareConnection = true;

	private boolean allowResultAccessAfterCompletion = false;

	private boolean hibernateManagedSession = false;

	@Nullable
	private Object entityInterceptor;

	
Just needed for entityInterceptorBeanName.

See Also:
  • setEntityInterceptorBeanName
/**
	 * Just needed for entityInterceptorBeanName.
	 * @see #setEntityInterceptorBeanName
	 */
	@Nullable
	private BeanFactory beanFactory;


	
Create a new HibernateTransactionManager instance.
A SessionFactory has to be set to be able to use it.

See Also:
  • setSessionFactory
/**
	 * Create a new HibernateTransactionManager instance.
	 * A SessionFactory has to be set to be able to use it.
	 * @see #setSessionFactory
	 */
	public HibernateTransactionManager() {
	}

	
Create a new HibernateTransactionManager instance.

Params:
  • sessionFactory – the SessionFactory to manage transactions for
/**
	 * Create a new HibernateTransactionManager instance.
	 * @param sessionFactory the SessionFactory to manage transactions for
	 */
	public HibernateTransactionManager(SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
		afterPropertiesSet();
	}


	
Set the SessionFactory that this instance should manage transactions for.

/**
	 * Set the SessionFactory that this instance should manage transactions for.
	 */
	public void setSessionFactory(@Nullable SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
	}

	
Return the SessionFactory that this instance should manage transactions for.

/**
	 * Return the SessionFactory that this instance should manage transactions for.
	 */
	@Nullable
	public SessionFactory getSessionFactory() {
		return this.sessionFactory;
	}

	
Obtain the SessionFactory for actual use.

Throws:
Returns:the SessionFactory (never null)
Since:5.0
/**
	 * Obtain the SessionFactory for actual use.
	 * @return the SessionFactory (never {@code null})
	 * @throws IllegalStateException in case of no SessionFactory set
	 * @since 5.0
	 */
	protected final SessionFactory obtainSessionFactory() {
		SessionFactory sessionFactory = getSessionFactory();
		Assert.state(sessionFactory != null, "No SessionFactory set");
		return sessionFactory;
	}

	
Set the JDBC DataSource that this instance should manage transactions for.
The DataSource should match the one used by the Hibernate SessionFactory:
for example, you could specify the same JNDI DataSource for both.

If the SessionFactory was configured with LocalDataSourceConnectionProvider,
i.e. by Spring's LocalSessionFactoryBean with a specified "dataSource",
the DataSource will be auto-detected: You can still explicitly specify the
DataSource, but you don't need to in this case.

A transactional JDBC Connection for this DataSource will be provided to
application code accessing this DataSource directly via DataSourceUtils
or JdbcTemplate. The Connection will be taken from the Hibernate Session.

The DataSource specified here should be the target DataSource to manage
transactions for, not a TransactionAwareDataSourceProxy. Only data access
code may work with TransactionAwareDataSourceProxy, while the transaction
manager needs to work on the underlying target DataSource. If there's
nevertheless a TransactionAwareDataSourceProxy passed in, it will be
unwrapped to extract its target DataSource.

NOTE: For scenarios with many transactions that just read data from Hibernate's cache (and do not actually access the database), consider using a LazyConnectionDataSourceProxy for the actual target DataSource. Alternatively, consider switching "prepareConnection" to false.
In both cases, this transaction manager will not eagerly acquire a
JDBC Connection for each Hibernate Session anymore (as of Spring 5.1).

See Also:
/**
	 * Set the JDBC DataSource that this instance should manage transactions for.
	 * The DataSource should match the one used by the Hibernate SessionFactory:
	 * for example, you could specify the same JNDI DataSource for both.
	 * <p>If the SessionFactory was configured with LocalDataSourceConnectionProvider,
	 * i.e. by Spring's LocalSessionFactoryBean with a specified "dataSource",
	 * the DataSource will be auto-detected: You can still explicitly specify the
	 * DataSource, but you don't need to in this case.
	 * <p>A transactional JDBC Connection for this DataSource will be provided to
	 * application code accessing this DataSource directly via DataSourceUtils
	 * or JdbcTemplate. The Connection will be taken from the Hibernate Session.
	 * <p>The DataSource specified here should be the target DataSource to manage
	 * transactions for, not a TransactionAwareDataSourceProxy. Only data access
	 * code may work with TransactionAwareDataSourceProxy, while the transaction
	 * manager needs to work on the underlying target DataSource. If there's
	 * nevertheless a TransactionAwareDataSourceProxy passed in, it will be
	 * unwrapped to extract its target DataSource.
	 * <p><b>NOTE: For scenarios with many transactions that just read data from
	 * Hibernate's cache (and do not actually access the database), consider using
	 * a {@link org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy}
	 * for the actual target DataSource. Alternatively, consider switching
	 * {@link #setPrepareConnection "prepareConnection"} to {@code false}.</b>
	 * In both cases, this transaction manager will not eagerly acquire a
	 * JDBC Connection for each Hibernate Session anymore (as of Spring 5.1).
	 * @see #setAutodetectDataSource
	 * @see TransactionAwareDataSourceProxy
	 * @see org.springframework.jdbc.datasource.LazyConnectionDataSourceProxy
	 * @see org.springframework.jdbc.core.JdbcTemplate
	 */
	public void setDataSource(@Nullable DataSource dataSource) {
		if (dataSource instanceof TransactionAwareDataSourceProxy) {
			// If we got a TransactionAwareDataSourceProxy, we need to perform transactions
			// for its underlying target DataSource, else data access code won't see
			// properly exposed transactions (i.e. transactions for the target DataSource).
			this.dataSource = ((TransactionAwareDataSourceProxy) dataSource).getTargetDataSource();
		}
		else {
			this.dataSource = dataSource;
		}
	}

	
Return the JDBC DataSource that this instance manages transactions for.

/**
	 * Return the JDBC DataSource that this instance manages transactions for.
	 */
	@Nullable
	public DataSource getDataSource() {
		return this.dataSource;
	}

	
Set whether to autodetect a JDBC DataSource used by the Hibernate SessionFactory, if set via LocalSessionFactoryBean's setDataSource. Default is "true". 
Can be turned off to deliberately ignore an available DataSource, in order
to not expose Hibernate transactions as JDBC transactions for that DataSource.

See Also:
/**
	 * Set whether to autodetect a JDBC DataSource used by the Hibernate SessionFactory,
	 * if set via LocalSessionFactoryBean's {@code setDataSource}. Default is "true".
	 * <p>Can be turned off to deliberately ignore an available DataSource, in order
	 * to not expose Hibernate transactions as JDBC transactions for that DataSource.
	 * @see #setDataSource
	 */
	public void setAutodetectDataSource(boolean autodetectDataSource) {
		this.autodetectDataSource = autodetectDataSource;
	}

	
Set whether to prepare the underlying JDBC Connection of a transactional
Hibernate Session, that is, whether to apply a transaction-specific
isolation level and/or the transaction's read-only flag to the underlying
JDBC Connection.

Default is "true". If you turn this flag off, the transaction manager will not support per-transaction isolation levels anymore. It will not call Connection.setReadOnly(true) for read-only transactions anymore either. If this flag is turned off, no cleanup of a JDBC Connection is required after a transaction, since no Connection settings will get modified. 
See Also:
/**
	 * Set whether to prepare the underlying JDBC Connection of a transactional
	 * Hibernate Session, that is, whether to apply a transaction-specific
	 * isolation level and/or the transaction's read-only flag to the underlying
	 * JDBC Connection.
	 * <p>Default is "true". If you turn this flag off, the transaction manager
	 * will not support per-transaction isolation levels anymore. It will not
	 * call {@code Connection.setReadOnly(true)} for read-only transactions
	 * anymore either. If this flag is turned off, no cleanup of a JDBC Connection
	 * is required after a transaction, since no Connection settings will get modified.
	 * @see Connection#setTransactionIsolation
	 * @see Connection#setReadOnly
	 */
	public void setPrepareConnection(boolean prepareConnection) {
		this.prepareConnection = prepareConnection;
	}

	
Set whether to allow result access after completion, typically via Hibernate's
ScrollableResults mechanism.

Default is "false". Turning this flag on enforces over-commit holdability on the underlying JDBC Connection (if "prepareConnection" is on) and skips the disconnect-on-completion step. 
See Also:
/**
	 * Set whether to allow result access after completion, typically via Hibernate's
	 * ScrollableResults mechanism.
	 * <p>Default is "false". Turning this flag on enforces over-commit holdability on the
	 * underlying JDBC Connection (if {@link #prepareConnection "prepareConnection"} is on)
	 * and skips the disconnect-on-completion step.
	 * @see Connection#setHoldability
	 * @see ResultSet#HOLD_CURSORS_OVER_COMMIT
	 * @see #disconnectOnCompletion(Session)
	 */
	public void setAllowResultAccessAfterCompletion(boolean allowResultAccessAfterCompletion) {
		this.allowResultAccessAfterCompletion = allowResultAccessAfterCompletion;
	}

	
Set whether to operate on a Hibernate-managed Session instead of a Spring-managed Session, that is, whether to obtain the Session through Hibernate's SessionFactory.getCurrentSession() instead of SessionFactory.openSession() (with a Spring TransactionSynchronizationManager check preceding it). 
Default is "false", i.e. using a Spring-managed Session: taking the current
thread-bound Session if available (e.g. in an Open-Session-in-View scenario),
creating a new Session for the current transaction otherwise.

Switch this flag to "true" in order to enforce use of a Hibernate-managed Session. Note that this requires SessionFactory.getCurrentSession() to always return a proper Session when called for a Spring-managed transaction; transaction begin will fail if the getCurrentSession() call fails. 
This mode will typically be used in combination with a custom Hibernate CurrentSessionContext implementation that stores Sessions in a place other than Spring's TransactionSynchronizationManager. It may also be used in combination with Spring's Open-Session-in-View support (using Spring's default SpringSessionContext), in which case it subtly differs from the Spring-managed Session mode: The pre-bound Session will not receive a clear() call (on rollback) or a disconnect() call (on transaction completion) in such a scenario; this is rather left up to a custom CurrentSessionContext implementation (if desired). 
/**
	 * Set whether to operate on a Hibernate-managed Session instead of a
	 * Spring-managed Session, that is, whether to obtain the Session through
	 * Hibernate's {@link SessionFactory#getCurrentSession()}
	 * instead of {@link SessionFactory#openSession()} (with a Spring
	 * {@link TransactionSynchronizationManager}
	 * check preceding it).
	 * <p>Default is "false", i.e. using a Spring-managed Session: taking the current
	 * thread-bound Session if available (e.g. in an Open-Session-in-View scenario),
	 * creating a new Session for the current transaction otherwise.
	 * <p>Switch this flag to "true" in order to enforce use of a Hibernate-managed Session.
	 * Note that this requires {@link SessionFactory#getCurrentSession()}
	 * to always return a proper Session when called for a Spring-managed transaction;
	 * transaction begin will fail if the {@code getCurrentSession()} call fails.
	 * <p>This mode will typically be used in combination with a custom Hibernate
	 * {@link org.hibernate.context.spi.CurrentSessionContext} implementation that stores
	 * Sessions in a place other than Spring's TransactionSynchronizationManager.
	 * It may also be used in combination with Spring's Open-Session-in-View support
	 * (using Spring's default {@link SpringSessionContext}), in which case it subtly
	 * differs from the Spring-managed Session mode: The pre-bound Session will <i>not</i>
	 * receive a {@code clear()} call (on rollback) or a {@code disconnect()}
	 * call (on transaction completion) in such a scenario; this is rather left up
	 * to a custom CurrentSessionContext implementation (if desired).
	 */
	public void setHibernateManagedSession(boolean hibernateManagedSession) {
		this.hibernateManagedSession = hibernateManagedSession;
	}

	
Set the bean name of a Hibernate entity interceptor that allows to inspect
and change property values before writing to and reading from the database.
Will get applied to any new Session created by this transaction manager.

Requires the bean factory to be known, to be able to resolve the bean
name to an interceptor instance on session creation. Typically used for
prototype interceptors, i.e. a new interceptor instance per session.

Can also be used for shared interceptor instances, but it is recommended
to set the interceptor reference directly in such a scenario.

Params:
  • entityInterceptorBeanName – the name of the entity interceptor in
the bean factory
See Also:
/**
	 * Set the bean name of a Hibernate entity interceptor that allows to inspect
	 * and change property values before writing to and reading from the database.
	 * Will get applied to any new Session created by this transaction manager.
	 * <p>Requires the bean factory to be known, to be able to resolve the bean
	 * name to an interceptor instance on session creation. Typically used for
	 * prototype interceptors, i.e. a new interceptor instance per session.
	 * <p>Can also be used for shared interceptor instances, but it is recommended
	 * to set the interceptor reference directly in such a scenario.
	 * @param entityInterceptorBeanName the name of the entity interceptor in
	 * the bean factory
	 * @see #setBeanFactory
	 * @see #setEntityInterceptor
	 */
	public void setEntityInterceptorBeanName(String entityInterceptorBeanName) {
		this.entityInterceptor = entityInterceptorBeanName;
	}

	
Set a Hibernate entity interceptor that allows to inspect and change
property values before writing to and reading from the database.
Will get applied to any new Session created by this transaction manager.

Such an interceptor can either be set at the SessionFactory level,
i.e. on LocalSessionFactoryBean, or at the Session level, i.e. on
HibernateTransactionManager.

See Also:
  • setEntityInterceptor.setEntityInterceptor
/**
	 * Set a Hibernate entity interceptor that allows to inspect and change
	 * property values before writing to and reading from the database.
	 * Will get applied to any new Session created by this transaction manager.
	 * <p>Such an interceptor can either be set at the SessionFactory level,
	 * i.e. on LocalSessionFactoryBean, or at the Session level, i.e. on
	 * HibernateTransactionManager.
	 * @see LocalSessionFactoryBean#setEntityInterceptor
	 */
	public void setEntityInterceptor(@Nullable Interceptor entityInterceptor) {
		this.entityInterceptor = entityInterceptor;
	}

	
Return the current Hibernate entity interceptor, or null if none. Resolves an entity interceptor bean name via the bean factory, if necessary. 
Throws:
See Also:
/**
	 * Return the current Hibernate entity interceptor, or {@code null} if none.
	 * Resolves an entity interceptor bean name via the bean factory,
	 * if necessary.
	 * @throws IllegalStateException if bean name specified but no bean factory set
	 * @throws BeansException if bean name resolution via the bean factory failed
	 * @see #setEntityInterceptor
	 * @see #setEntityInterceptorBeanName
	 * @see #setBeanFactory
	 */
	@Nullable
	public Interceptor getEntityInterceptor() throws IllegalStateException, BeansException {
		if (this.entityInterceptor instanceof Interceptor) {
			return (Interceptor) this.entityInterceptor;
		}
		else if (this.entityInterceptor instanceof String) {
			if (this.beanFactory == null) {
				throw new IllegalStateException("Cannot get entity interceptor via bean name if no bean factory set");
			}
			String beanName = (String) this.entityInterceptor;
			return this.beanFactory.getBean(beanName, Interceptor.class);
		}
		else {
			return null;
		}
	}

	
The bean factory just needs to be known for resolving entity interceptor
bean names. It does not need to be set for any other mode of operation.

See Also:
  • setEntityInterceptorBeanName
/**
	 * The bean factory just needs to be known for resolving entity interceptor
	 * bean names. It does not need to be set for any other mode of operation.
	 * @see #setEntityInterceptorBeanName
	 */
	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}

	@Override
	public void afterPropertiesSet() {
		if (getSessionFactory() == null) {
			throw new IllegalArgumentException("Property 'sessionFactory' is required");
		}
		if (this.entityInterceptor instanceof String && this.beanFactory == null) {
			throw new IllegalArgumentException("Property 'beanFactory' is required for 'entityInterceptorBeanName'");
		}

		// Check for SessionFactory's DataSource.
		if (this.autodetectDataSource && getDataSource() == null) {
			DataSource sfds = SessionFactoryUtils.getDataSource(getSessionFactory());
			if (sfds != null) {
				// Use the SessionFactory's DataSource for exposing transactions to JDBC code.
				if (logger.isDebugEnabled()) {
					logger.debug("Using DataSource [" + sfds +
							"] of Hibernate SessionFactory for HibernateTransactionManager");
				}
				setDataSource(sfds);
			}
		}
	}


	@Override
	public Object getResourceFactory() {
		return obtainSessionFactory();
	}

	@Override
	protected Object doGetTransaction() {
		HibernateTransactionObject txObject = new HibernateTransactionObject();
		txObject.setSavepointAllowed(isNestedTransactionAllowed());

		SessionFactory sessionFactory = obtainSessionFactory();
		SessionHolder sessionHolder =
				(SessionHolder) TransactionSynchronizationManager.getResource(sessionFactory);
		if (sessionHolder != null) {
			if (logger.isDebugEnabled()) {
				logger.debug("Found thread-bound Session [" + sessionHolder.getSession() + "] for Hibernate transaction");
			}
			txObject.setSessionHolder(sessionHolder);
		}
		else if (this.hibernateManagedSession) {
			try {
				Session session = sessionFactory.getCurrentSession();
				if (logger.isDebugEnabled()) {
					logger.debug("Found Hibernate-managed Session [" + session + "] for Spring-managed transaction");
				}
				txObject.setExistingSession(session);
			}
			catch (HibernateException ex) {
				throw new DataAccessResourceFailureException(
						"Could not obtain Hibernate-managed Session for Spring-managed transaction", ex);
			}
		}

		if (getDataSource() != null) {
			ConnectionHolder conHolder = (ConnectionHolder)
					TransactionSynchronizationManager.getResource(getDataSource());
			txObject.setConnectionHolder(conHolder);
		}

		return txObject;
	}

	@Override
	protected boolean isExistingTransaction(Object transaction) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;
		return (txObject.hasSpringManagedTransaction() ||
				(this.hibernateManagedSession && txObject.hasHibernateManagedTransaction()));
	}

	@Override
	@SuppressWarnings("deprecation")
	protected void doBegin(Object transaction, TransactionDefinition definition) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;

		if (txObject.hasConnectionHolder() && !txObject.getConnectionHolder().isSynchronizedWithTransaction()) {
			throw new IllegalTransactionStateException(
					"Pre-bound JDBC Connection found! HibernateTransactionManager does not support " +
					"running within DataSourceTransactionManager if told to manage the DataSource itself. " +
					"It is recommended to use a single HibernateTransactionManager for all transactions " +
					"on a single DataSource, no matter whether Hibernate or JDBC access.");
		}

		Session session = null;

		try {
			if (!txObject.hasSessionHolder() || txObject.getSessionHolder().isSynchronizedWithTransaction()) {
				Interceptor entityInterceptor = getEntityInterceptor();
				Session newSession = (entityInterceptor != null ?
						obtainSessionFactory().withOptions().interceptor(entityInterceptor).openSession() :
						obtainSessionFactory().openSession());
				if (logger.isDebugEnabled()) {
					logger.debug("Opened new Session [" + newSession + "] for Hibernate transaction");
				}
				txObject.setSession(newSession);
			}

			session = txObject.getSessionHolder().getSession();

			boolean holdabilityNeeded = this.allowResultAccessAfterCompletion && !txObject.isNewSession();
			boolean isolationLevelNeeded = (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT);
			if (holdabilityNeeded || isolationLevelNeeded || definition.isReadOnly()) {
				if (this.prepareConnection && isSameConnectionForEntireSession(session)) {
					// We're allowed to change the transaction settings of the JDBC Connection.
					if (logger.isDebugEnabled()) {
						logger.debug("Preparing JDBC Connection of Hibernate Session [" + session + "]");
					}
					Connection con = ((SessionImplementor) session).connection();
					Integer previousIsolationLevel = DataSourceUtils.prepareConnectionForTransaction(con, definition);
					txObject.setPreviousIsolationLevel(previousIsolationLevel);
					if (this.allowResultAccessAfterCompletion && !txObject.isNewSession()) {
						int currentHoldability = con.getHoldability();
						if (currentHoldability != ResultSet.HOLD_CURSORS_OVER_COMMIT) {
							txObject.setPreviousHoldability(currentHoldability);
							con.setHoldability(ResultSet.HOLD_CURSORS_OVER_COMMIT);
						}
					}
				}
				else {
					// Not allowed to change the transaction settings of the JDBC Connection.
					if (isolationLevelNeeded) {
						// We should set a specific isolation level but are not allowed to...
						throw new InvalidIsolationLevelException(
								"HibernateTransactionManager is not allowed to support custom isolation levels: " +
								"make sure that its 'prepareConnection' flag is on (the default) and that the " +
								"Hibernate connection release mode is set to 'on_close' (the default for JDBC).");
					}
					if (logger.isDebugEnabled()) {
						logger.debug("Not preparing JDBC Connection of Hibernate Session [" + session + "]");
					}
				}
			}

			if (definition.isReadOnly() && txObject.isNewSession()) {
				// Just set to MANUAL in case of a new Session for this transaction.
				session.setFlushMode(FlushMode.MANUAL);
				// As of 5.1, we're also setting Hibernate's read-only entity mode by default.
				session.setDefaultReadOnly(true);
			}

			if (!definition.isReadOnly() && !txObject.isNewSession()) {
				// We need AUTO or COMMIT for a non-read-only transaction.
				FlushMode flushMode = SessionFactoryUtils.getFlushMode(session);
				if (FlushMode.MANUAL.equals(flushMode)) {
					session.setFlushMode(FlushMode.AUTO);
					txObject.getSessionHolder().setPreviousFlushMode(flushMode);
				}
			}

			Transaction hibTx;

			// Register transaction timeout.
			int timeout = determineTimeout(definition);
			if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
				// Use Hibernate's own transaction timeout mechanism on Hibernate 3.1+
				// Applies to all statements, also to inserts, updates and deletes!
				hibTx = session.getTransaction();
				hibTx.setTimeout(timeout);
				hibTx.begin();
			}
			else {
				// Open a plain Hibernate transaction without specified timeout.
				hibTx = session.beginTransaction();
			}

			// Add the Hibernate transaction to the session holder.
			txObject.getSessionHolder().setTransaction(hibTx);

			// Register the Hibernate Session's JDBC Connection for the DataSource, if set.
			if (getDataSource() != null) {
				SessionImplementor sessionImpl = (SessionImplementor) session;
				// The following needs to use a lambda expression instead of a method reference
				// for compatibility with Hibernate ORM <5.2 where connection() is defined on
				// SessionImplementor itself instead of on SharedSessionContractImplementor...
				ConnectionHolder conHolder = new ConnectionHolder(() -> sessionImpl.connection());
				if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
					conHolder.setTimeoutInSeconds(timeout);
				}
				if (logger.isDebugEnabled()) {
					logger.debug("Exposing Hibernate transaction as JDBC [" + conHolder.getConnectionHandle() + "]");
				}
				TransactionSynchronizationManager.bindResource(getDataSource(), conHolder);
				txObject.setConnectionHolder(conHolder);
			}

			// Bind the session holder to the thread.
			if (txObject.isNewSessionHolder()) {
				TransactionSynchronizationManager.bindResource(obtainSessionFactory(), txObject.getSessionHolder());
			}
			txObject.getSessionHolder().setSynchronizedWithTransaction(true);
		}

		catch (Throwable ex) {
			if (txObject.isNewSession()) {
				try {
					if (session != null && session.getTransaction().getStatus() == TransactionStatus.ACTIVE) {
						session.getTransaction().rollback();
					}
				}
				catch (Throwable ex2) {
					logger.debug("Could not rollback Session after failed transaction begin", ex);
				}
				finally {
					SessionFactoryUtils.closeSession(session);
					txObject.setSessionHolder(null);
				}
			}
			throw new CannotCreateTransactionException("Could not open Hibernate Session for transaction", ex);
		}
	}

	@Override
	protected Object doSuspend(Object transaction) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;
		txObject.setSessionHolder(null);
		SessionHolder sessionHolder =
				(SessionHolder) TransactionSynchronizationManager.unbindResource(obtainSessionFactory());
		txObject.setConnectionHolder(null);
		ConnectionHolder connectionHolder = null;
		if (getDataSource() != null) {
			connectionHolder = (ConnectionHolder) TransactionSynchronizationManager.unbindResource(getDataSource());
		}
		return new SuspendedResourcesHolder(sessionHolder, connectionHolder);
	}

	@Override
	protected void doResume(@Nullable Object transaction, Object suspendedResources) {
		SessionFactory sessionFactory = obtainSessionFactory();

		SuspendedResourcesHolder resourcesHolder = (SuspendedResourcesHolder) suspendedResources;
		if (TransactionSynchronizationManager.hasResource(sessionFactory)) {
			// From non-transactional code running in active transaction synchronization
			// -> can be safely removed, will be closed on transaction completion.
			TransactionSynchronizationManager.unbindResource(sessionFactory);
		}
		TransactionSynchronizationManager.bindResource(sessionFactory, resourcesHolder.getSessionHolder());
		if (getDataSource() != null && resourcesHolder.getConnectionHolder() != null) {
			TransactionSynchronizationManager.bindResource(getDataSource(), resourcesHolder.getConnectionHolder());
		}
	}

	@Override
	protected void doCommit(DefaultTransactionStatus status) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) status.getTransaction();
		Transaction hibTx = txObject.getSessionHolder().getTransaction();
		Assert.state(hibTx != null, "No Hibernate transaction");
		if (status.isDebug()) {
			logger.debug("Committing Hibernate transaction on Session [" +
					txObject.getSessionHolder().getSession() + "]");
		}

		try {
			hibTx.commit();
		}
		catch (org.hibernate.TransactionException ex) {
			// assumably from commit call to the underlying JDBC connection
			throw new TransactionSystemException("Could not commit Hibernate transaction", ex);
		}
		catch (HibernateException ex) {
			// assumably failed to flush changes to database
			throw convertHibernateAccessException(ex);
		}
		catch (PersistenceException ex) {
			if (ex.getCause() instanceof HibernateException) {
				throw convertHibernateAccessException((HibernateException) ex.getCause());
			}
			throw ex;
		}
	}

	@Override
	protected void doRollback(DefaultTransactionStatus status) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) status.getTransaction();
		Transaction hibTx = txObject.getSessionHolder().getTransaction();
		Assert.state(hibTx != null, "No Hibernate transaction");
		if (status.isDebug()) {
			logger.debug("Rolling back Hibernate transaction on Session [" +
					txObject.getSessionHolder().getSession() + "]");
		}

		try {
			hibTx.rollback();
		}
		catch (org.hibernate.TransactionException ex) {
			throw new TransactionSystemException("Could not roll back Hibernate transaction", ex);
		}
		catch (HibernateException ex) {
			// Shouldn't really happen, as a rollback doesn't cause a flush.
			throw convertHibernateAccessException(ex);
		}
		catch (PersistenceException ex) {
			if (ex.getCause() instanceof HibernateException) {
				throw convertHibernateAccessException((HibernateException) ex.getCause());
			}
			throw ex;
		}
		finally {
			if (!txObject.isNewSession() && !this.hibernateManagedSession) {
				// Clear all pending inserts/updates/deletes in the Session.
				// Necessary for pre-bound Sessions, to avoid inconsistent state.
				txObject.getSessionHolder().getSession().clear();
			}
		}
	}

	@Override
	protected void doSetRollbackOnly(DefaultTransactionStatus status) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) status.getTransaction();
		if (status.isDebug()) {
			logger.debug("Setting Hibernate transaction on Session [" +
					txObject.getSessionHolder().getSession() + "] rollback-only");
		}
		txObject.setRollbackOnly();
	}

	@Override
	@SuppressWarnings("deprecation")
	protected void doCleanupAfterCompletion(Object transaction) {
		HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;

		// Remove the session holder from the thread.
		if (txObject.isNewSessionHolder()) {
			TransactionSynchronizationManager.unbindResource(obtainSessionFactory());
		}

		// Remove the JDBC connection holder from the thread, if exposed.
		if (getDataSource() != null) {
			TransactionSynchronizationManager.unbindResource(getDataSource());
		}

		Session session = txObject.getSessionHolder().getSession();
		if (this.prepareConnection && isPhysicallyConnected(session)) {
			// We're running with connection release mode "on_close": We're able to reset
			// the isolation level and/or read-only flag of the JDBC Connection here.
			// Else, we need to rely on the connection pool to perform proper cleanup.
			try {
				Connection con = ((SessionImplementor) session).connection();
				Integer previousHoldability = txObject.getPreviousHoldability();
				if (previousHoldability != null) {
					con.setHoldability(previousHoldability);
				}
				DataSourceUtils.resetConnectionAfterTransaction(con, txObject.getPreviousIsolationLevel());
			}
			catch (HibernateException ex) {
				logger.debug("Could not access JDBC Connection of Hibernate Session", ex);
			}
			catch (Throwable ex) {
				logger.debug("Could not reset JDBC Connection after transaction", ex);
			}
		}

		if (txObject.isNewSession()) {
			if (logger.isDebugEnabled()) {
				logger.debug("Closing Hibernate Session [" + session + "] after transaction");
			}
			SessionFactoryUtils.closeSession(session);
		}
		else {
			if (logger.isDebugEnabled()) {
				logger.debug("Not closing pre-bound Hibernate Session [" + session + "] after transaction");
			}
			if (txObject.getSessionHolder().getPreviousFlushMode() != null) {
				session.setFlushMode(txObject.getSessionHolder().getPreviousFlushMode());
			}
			if (!this.allowResultAccessAfterCompletion && !this.hibernateManagedSession) {
				disconnectOnCompletion(session);
			}
		}
		txObject.getSessionHolder().clear();
	}

	
Disconnect a pre-existing Hibernate Session on transaction completion,
returning its database connection but preserving its entity state.

The default implementation simply calls Session.disconnect(). Subclasses may override this with a no-op or with fine-tuned disconnection logic. 
Params:
  • session – the Hibernate Session to disconnect
See Also:
/**
	 * Disconnect a pre-existing Hibernate Session on transaction completion,
	 * returning its database connection but preserving its entity state.
	 * <p>The default implementation simply calls {@link Session#disconnect()}.
	 * Subclasses may override this with a no-op or with fine-tuned disconnection logic.
	 * @param session the Hibernate Session to disconnect
	 * @see Session#disconnect()
	 */
	protected void disconnectOnCompletion(Session session) {
		session.disconnect();
	}

	
Return whether the given Hibernate Session will always hold the same
JDBC Connection. This is used to check whether the transaction manager
can safely prepare and clean up the JDBC Connection used for a transaction.

The default implementation checks the Session's connection release mode
to be "on_close".

Params:
  • session – the Hibernate Session to check
See Also:
/**
	 * Return whether the given Hibernate Session will always hold the same
	 * JDBC Connection. This is used to check whether the transaction manager
	 * can safely prepare and clean up the JDBC Connection used for a transaction.
	 * <p>The default implementation checks the Session's connection release mode
	 * to be "on_close".
	 * @param session the Hibernate Session to check
	 * @see ConnectionReleaseMode#ON_CLOSE
	 */
	@SuppressWarnings("deprecation")
	protected boolean isSameConnectionForEntireSession(Session session) {
		if (!(session instanceof SessionImplementor)) {
			// The best we can do is to assume we're safe.
			return true;
		}
		ConnectionReleaseMode releaseMode =
				((SessionImplementor) session).getJdbcCoordinator().getConnectionReleaseMode();
		return ConnectionReleaseMode.ON_CLOSE.equals(releaseMode);
	}

	
Determine whether the given Session is (still) physically connected
to the database, that is, holds an active JDBC Connection internally.

Params:
  • session – the Hibernate Session to check
See Also:
/**
	 * Determine whether the given Session is (still) physically connected
	 * to the database, that is, holds an active JDBC Connection internally.
	 * @param session the Hibernate Session to check
	 * @see #isSameConnectionForEntireSession(Session)
	 */
	protected boolean isPhysicallyConnected(Session session) {
		if (!(session instanceof SessionImplementor)) {
			// The best we can do is to check whether we're logically connected.
			return session.isConnected();
		}
		return ((SessionImplementor) session).getJdbcCoordinator().getLogicalConnection().isPhysicallyConnected();
	}


	
Convert the given HibernateException to an appropriate exception from the org.springframework.dao hierarchy. 
Will automatically apply a specified SQLExceptionTranslator to a
Hibernate JDBCException, else rely on Hibernate's default translation.

Params:
  • ex – the HibernateException that occurred
See Also:
Returns:a corresponding DataAccessException
/**
	 * Convert the given HibernateException to an appropriate exception
	 * from the {@code org.springframework.dao} hierarchy.
	 * <p>Will automatically apply a specified SQLExceptionTranslator to a
	 * Hibernate JDBCException, else rely on Hibernate's default translation.
	 * @param ex the HibernateException that occurred
	 * @return a corresponding DataAccessException
	 * @see SessionFactoryUtils#convertHibernateAccessException
	 */
	protected DataAccessException convertHibernateAccessException(HibernateException ex) {
		return SessionFactoryUtils.convertHibernateAccessException(ex);
	}


	
Hibernate transaction object, representing a SessionHolder.
Used as transaction object by HibernateTransactionManager.

/**
	 * Hibernate transaction object, representing a SessionHolder.
	 * Used as transaction object by HibernateTransactionManager.
	 */
	private class HibernateTransactionObject extends JdbcTransactionObjectSupport {

		@Nullable
		private SessionHolder sessionHolder;

		private boolean newSessionHolder;

		private boolean newSession;

		@Nullable
		private Integer previousHoldability;

		public void setSession(Session session) {
			this.sessionHolder = new SessionHolder(session);
			this.newSessionHolder = true;
			this.newSession = true;
		}

		public void setExistingSession(Session session) {
			this.sessionHolder = new SessionHolder(session);
			this.newSessionHolder = true;
			this.newSession = false;
		}

		public void setSessionHolder(@Nullable SessionHolder sessionHolder) {
			this.sessionHolder = sessionHolder;
			this.newSessionHolder = false;
			this.newSession = false;
		}

		public SessionHolder getSessionHolder() {
			Assert.state(this.sessionHolder != null, "No SessionHolder available");
			return this.sessionHolder;
		}

		public boolean hasSessionHolder() {
			return (this.sessionHolder != null);
		}

		public boolean isNewSessionHolder() {
			return this.newSessionHolder;
		}

		public boolean isNewSession() {
			return this.newSession;
		}

		public void setPreviousHoldability(@Nullable Integer previousHoldability) {
			this.previousHoldability = previousHoldability;
		}

		@Nullable
		public Integer getPreviousHoldability() {
			return this.previousHoldability;
		}

		public boolean hasSpringManagedTransaction() {
			return (this.sessionHolder != null && this.sessionHolder.getTransaction() != null);
		}

		public boolean hasHibernateManagedTransaction() {
			return (this.sessionHolder != null &&
					this.sessionHolder.getSession().getTransaction().getStatus() == TransactionStatus.ACTIVE);
		}

		public void setRollbackOnly() {
			getSessionHolder().setRollbackOnly();
			if (hasConnectionHolder()) {
				getConnectionHolder().setRollbackOnly();
			}
		}

		@Override
		public boolean isRollbackOnly() {
			return getSessionHolder().isRollbackOnly() ||
					(hasConnectionHolder() && getConnectionHolder().isRollbackOnly());
		}

		@Override
		public void flush() {
			try {
				getSessionHolder().getSession().flush();
			}
			catch (HibernateException ex) {
				throw convertHibernateAccessException(ex);
			}
			catch (PersistenceException ex) {
				if (ex.getCause() instanceof HibernateException) {
					throw convertHibernateAccessException((HibernateException) ex.getCause());
				}
				throw ex;
			}
		}
	}


	
Holder for suspended resources. Used internally by doSuspend and doResume. 
/**
	 * Holder for suspended resources.
	 * Used internally by {@code doSuspend} and {@code doResume}.
	 */
	private static final class SuspendedResourcesHolder {

		private final SessionHolder sessionHolder;

		@Nullable
		private final ConnectionHolder connectionHolder;

		private SuspendedResourcesHolder(SessionHolder sessionHolder, @Nullable ConnectionHolder conHolder) {
			this.sessionHolder = sessionHolder;
			this.connectionHolder = conHolder;
		}

		private SessionHolder getSessionHolder() {
			return this.sessionHolder;
		}

		@Nullable
		private ConnectionHolder getConnectionHolder() {
			return this.connectionHolder;
		}
	}

}