Java tutorial
package com.byteslounge.spring.tx; /* * Copyright 2002-2012 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. */ import java.sql.Connection; import javax.sql.DataSource; import org.hibernate.ConnectionReleaseMode; import org.hibernate.FlushMode; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.engine.spi.SessionImplementor; import org.hibernate.engine.transaction.spi.TransactionContext; 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.orm.hibernate4.SessionFactoryUtils; import org.springframework.orm.hibernate4.SessionHolder; import org.springframework.orm.hibernate4.SpringSessionContext; 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; /** * {@link org.springframework.transaction.PlatformTransactionManager} * implementation for a single Hibernate {@link org.hibernate.SessionFactory}. * Binds a Hibernate Session from the specified factory to the thread, * potentially allowing for one thread-bound Session per factory. * <code>SessionFactory.getCurrentSession()</code> 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>On JDBC 3.0, 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 objects. 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 3.1 * @see #setSessionFactory * @see #setDataSource * @see org.hibernate.SessionFactory#getCurrentSession() * @see org.springframework.jdbc.datasource.DataSourceUtils#getConnection * @see org.springframework.jdbc.datasource.DataSourceUtils#releaseConnection * @see org.springframework.jdbc.core.JdbcTemplate * @see org.springframework.jdbc.datasource.DataSourceTransactionManager * @see org.springframework.transaction.jta.JtaTransactionManager */ @SuppressWarnings("serial") public class MyOwnTxManager extends AbstractPlatformTransactionManager implements ResourceTransactionManager, InitializingBean { private SessionFactory sessionFactory; private DataSource dataSource; private boolean autodetectDataSource = true; private boolean prepareConnection = true; private boolean hibernateManagedSession = false; /** * Create a new HibernateTransactionManager instance. * A SessionFactory has to be set to be able to use it. * @see #setSessionFactory */ public MyOwnTxManager() { } /** * Create a new HibernateTransactionManager instance. * @param sessionFactory SessionFactory to manage transactions for */ public MyOwnTxManager(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; afterPropertiesSet(); } /** * Set the SessionFactory that this instance should manage transactions for. */ public void setSessionFactory(SessionFactory sessionFactory) { this.sessionFactory = sessionFactory; } /** * Return the SessionFactory that this instance should manage transactions for. */ public SessionFactory getSessionFactory() { return this.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. * <p>If the SessionFactory was configured with LocalDataSourceConnectionProvider, * i.e. by Spring's SessionFactoryBuilder with a specified "dataSource", * the DataSource will be auto-detected: You can still explictly 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. * @see #setAutodetectDataSource * @see org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy * @see org.springframework.jdbc.datasource.DataSourceUtils * @see org.springframework.jdbc.core.JdbcTemplate */ public void setDataSource(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. */ public DataSource getDataSource() { return this.dataSource; } /** * Set whether to autodetect a JDBC DataSource used by the Hibernate SessionFactory, * if set via SessionFactoryBuilder's <code>setDataSource</code>. 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. * <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)</code> 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 java.sql.Connection#setTransactionIsolation * @see java.sql.Connection#setReadOnly */ public void setPrepareConnection(boolean prepareConnection) { this.prepareConnection = prepareConnection; } /** * 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 org.hibernate.SessionFactory#getCurrentSession()} * instead of {@link org.hibernate.SessionFactory#openSession()} (with a Spring * {@link org.springframework.transaction.support.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 org.hibernate.SessionFactory#getCurrentSession()} * to always return a proper Session when called for a Spring-managed transaction; * transaction begin will fail if the <code>getCurrentSession()</code> call fails. * <p>This mode will typically be used in combination with a custom Hibernate * {@link org.hibernate.context.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()</code> call (on rollback) or a <code>disconnect()</code> * 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; } public void afterPropertiesSet() { if (getSessionFactory() == null) { throw new IllegalArgumentException("Property 'sessionFactory' is required"); } // 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.isInfoEnabled()) { logger.info("Using DataSource [" + sfds + "] of Hibernate SessionFactory for HibernateTransactionManager"); } setDataSource(sfds); } } } public Object getResourceFactory() { return getSessionFactory(); } @Override protected Object doGetTransaction() { HibernateTransactionObject txObject = new HibernateTransactionObject(); txObject.setSavepointAllowed(isNestedTransactionAllowed()); SessionHolder sessionHolder = (SessionHolder) TransactionSynchronizationManager .getResource(getSessionFactory()); 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 = this.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 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.getSessionHolder() == null || txObject.getSessionHolder().isSynchronizedWithTransaction()) { Session newSession = getSessionFactory().openSession(); if (logger.isDebugEnabled()) { logger.debug("Opened new Session [" + newSession + "] for Hibernate transaction"); } txObject.setSession(newSession); } session = txObject.getSessionHolder().getSession(); 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(); if (con.isClosed()) { System.out.println("Connection closed by exception"); } Integer previousIsolationLevel = DataSourceUtils.prepareConnectionForTransaction(con, definition); txObject.setPreviousIsolationLevel(previousIsolationLevel); } else { // Not allowed to change the transaction settings of the JDBC Connection. if (definition.getIsolationLevel() != TransactionDefinition.ISOLATION_DEFAULT) { // 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' (SpringTransactionFactory's default)."); } if (logger.isDebugEnabled()) { logger.debug("Not preparing JDBC Connection of Hibernate Session [" + session + "]"); } } if (definition.isReadOnly() && txObject.isNewSession()) { // Just set to NEVER in case of a new Session for this transaction. session.setFlushMode(FlushMode.MANUAL); } if (!definition.isReadOnly() && !txObject.isNewSession()) { // We need AUTO or COMMIT for a non-read-only transaction. FlushMode flushMode = session.getFlushMode(); if (FlushMode.isManualFlushMode(session.getFlushMode())) { 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) { Connection con = ((SessionImplementor) session).connection(); ConnectionHolder conHolder = new ConnectionHolder(con); if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) { conHolder.setTimeoutInSeconds(timeout); } if (logger.isDebugEnabled()) { logger.debug("Exposing Hibernate transaction as JDBC transaction [" + con + "]"); } TransactionSynchronizationManager.bindResource(getDataSource(), conHolder); txObject.setConnectionHolder(conHolder); } // Bind the session holder to the thread. if (txObject.isNewSessionHolder()) { TransactionSynchronizationManager.bindResource(getSessionFactory(), txObject.getSessionHolder()); } txObject.getSessionHolder().setSynchronizedWithTransaction(true); } catch (Exception ex) { if (txObject.isNewSession()) { try { if (session.getTransaction().isActive()) { session.getTransaction().rollback(); } } catch (Throwable ex2) { logger.debug("Could not rollback Session after failed transaction begin", ex); } finally { SessionFactoryUtils.closeSession(session); } } 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(getSessionFactory()); txObject.setConnectionHolder(null); ConnectionHolder connectionHolder = null; if (getDataSource() != null) { connectionHolder = (ConnectionHolder) TransactionSynchronizationManager.unbindResource(getDataSource()); } return new SuspendedResourcesHolder(sessionHolder, connectionHolder); } @Override protected void doResume(Object transaction, Object suspendedResources) { SuspendedResourcesHolder resourcesHolder = (SuspendedResourcesHolder) suspendedResources; if (TransactionSynchronizationManager.hasResource(getSessionFactory())) { // From non-transactional code running in active transaction synchronization // -> can be safely removed, will be closed on transaction completion. TransactionSynchronizationManager.unbindResource(getSessionFactory()); } TransactionSynchronizationManager.bindResource(getSessionFactory(), resourcesHolder.getSessionHolder()); if (getDataSource() != null) { TransactionSynchronizationManager.bindResource(getDataSource(), resourcesHolder.getConnectionHolder()); } } @Override protected void doCommit(DefaultTransactionStatus status) { HibernateTransactionObject txObject = (HibernateTransactionObject) status.getTransaction(); if (status.isDebug()) { logger.debug("Committing Hibernate transaction on Session [" + txObject.getSessionHolder().getSession() + "]"); } try { txObject.getSessionHolder().getTransaction().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); } } @Override protected void doRollback(DefaultTransactionStatus status) { HibernateTransactionObject txObject = (HibernateTransactionObject) status.getTransaction(); if (status.isDebug()) { logger.debug("Rolling back Hibernate transaction on Session [" + txObject.getSessionHolder().getSession() + "]"); } try { txObject.getSessionHolder().getTransaction().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); } 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 protected void doCleanupAfterCompletion(Object transaction) { HibernateTransactionObject txObject = (HibernateTransactionObject) transaction; // Remove the session holder from the thread. if (txObject.isNewSessionHolder()) { TransactionSynchronizationManager.unbindResource(getSessionFactory()); } // Remove the JDBC connection holder from the thread, if exposed. if (getDataSource() != null) { TransactionSynchronizationManager.unbindResource(getDataSource()); } Session session = txObject.getSessionHolder().getSession(); if (this.prepareConnection && session.isConnected() && isSameConnectionForEntireSession(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(); DataSourceUtils.resetConnectionAfterTransaction(con, txObject.getPreviousIsolationLevel()); } catch (HibernateException ex) { logger.debug("Could not access JDBC Connection of Hibernate Session", 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.hibernateManagedSession) { session.disconnect(); } } txObject.getSessionHolder().clear(); } /** * 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 org.hibernate.engine.transaction.spi.TransactionContext#getConnectionReleaseMode() * @see org.hibernate.ConnectionReleaseMode#ON_CLOSE */ protected boolean isSameConnectionForEntireSession(Session session) { if (!(session instanceof TransactionContext)) { // The best we can do is to assume we're safe. return true; } ConnectionReleaseMode releaseMode = ((TransactionContext) session).getConnectionReleaseMode(); return ConnectionReleaseMode.ON_CLOSE.equals(releaseMode); } /** * Convert the given HibernateException to an appropriate exception * from the <code>org.springframework.dao</code> hierarchy. * <p>Will automatically apply a specified SQLExceptionTranslator to a * Hibernate JDBCException, else rely on Hibernate's default translation. * @param ex HibernateException that occured * @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. */ private class HibernateTransactionObject extends JdbcTransactionObjectSupport { private SessionHolder sessionHolder; private boolean newSessionHolder; private boolean newSession; 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(SessionHolder sessionHolder) { this.sessionHolder = sessionHolder; this.newSessionHolder = false; this.newSession = false; } public SessionHolder getSessionHolder() { return this.sessionHolder; } public boolean isNewSessionHolder() { return this.newSessionHolder; } public boolean isNewSession() { return this.newSession; } public boolean hasSpringManagedTransaction() { return (this.sessionHolder != null && this.sessionHolder.getTransaction() != null); } public boolean hasHibernateManagedTransaction() { return (this.sessionHolder != null && this.sessionHolder.getSession().getTransaction().isActive()); } public void setRollbackOnly() { this.sessionHolder.setRollbackOnly(); if (hasConnectionHolder()) { getConnectionHolder().setRollbackOnly(); } } public boolean isRollbackOnly() { return this.sessionHolder.isRollbackOnly() || (hasConnectionHolder() && getConnectionHolder().isRollbackOnly()); } @Override public void flush() { try { this.sessionHolder.getSession().flush(); } catch (HibernateException ex) { throw convertHibernateAccessException(ex); } } } /** * Holder for suspended resources. * Used internally by <code>doSuspend</code> and <code>doResume</code>. */ private static class SuspendedResourcesHolder { private final SessionHolder sessionHolder; private final ConnectionHolder connectionHolder; private SuspendedResourcesHolder(SessionHolder sessionHolder, ConnectionHolder conHolder) { this.sessionHolder = sessionHolder; this.connectionHolder = conHolder; } private SessionHolder getSessionHolder() { return this.sessionHolder; } private ConnectionHolder getConnectionHolder() { return this.connectionHolder; } } }