connectionfactoryutils.java

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	 * Obtain a JMS Session that is synchronized with the current transaction, if any.
	 * <p>This <code>doGetTransactionalSession</code> variant always starts the underlying
	 * JMS Connection, assuming that the Session will be used for receiving messages.
	 * @param connectionFactory the JMS ConnectionFactory to bind for
	 * (used as TransactionSynchronizationManager key)
	 * @param resourceFactory the ResourceFactory to use for extracting or creating
	 * JMS resources
	 * @return the transactional Session, or <code>null</code> if none found
	 * @throws JMSException in case of JMS failure
	 * @see #doGetTransactionalSession(javax.jms.ConnectionFactory, ResourceFactory, boolean)
	 */
	public static Session doGetTransactionalSession(
			ConnectionFactory connectionFactory, ResourceFactory resourceFactory) throws JMSException {

		return doGetTransactionalSession(connectionFactory, resourceFactory, true);
	}

	/**
	 * Obtain a JMS Session that is synchronized with the current transaction, if any.
	 * @param connectionFactory the JMS ConnectionFactory to bind for
	 * (used as TransactionSynchronizationManager key)
	 * @param resourceFactory the ResourceFactory to use for extracting or creating
	 * JMS resources
	 * @param startConnection whether the underlying JMS Connection approach should be
	 * started in order to allow for receiving messages. Note that a reused Connection
	 * may already have been started before, even if this flag is <code>false</code>.
	 * @return the transactional Session, or <code>null</code> if none found
	 * @throws JMSException in case of JMS failure
	 */
	public static Session doGetTransactionalSession(
			ConnectionFactory connectionFactory, ResourceFactory resourceFactory, boolean startConnection)
			throws JMSException {

		Assert.notNull(connectionFactory, "ConnectionFactory must not be null");
		Assert.notNull(resourceFactory, "ResourceFactory must not be null");

		JmsResourceHolder resourceHolder =
				(JmsResourceHolder) TransactionSynchronizationManager.getResource(connectionFactory);
		if (resourceHolder != null) {
			Session session = resourceFactory.getSession(resourceHolder);
			if (session != null) {
				if (startConnection) {
					Connection con = resourceFactory.getConnection(resourceHolder);
					if (con != null) {
						con.start();
					}
				}
				return session;
			}
			if (resourceHolder.isFrozen()) {
				return null;
			}
		}
		if (!TransactionSynchronizationManager.isSynchronizationActive()) {
			return null;
		}
		JmsResourceHolder resourceHolderToUse = resourceHolder;
		if (resourceHolderToUse == null) {
			resourceHolderToUse = new JmsResourceHolder(connectionFactory);
		}
		Connection con = resourceFactory.getConnection(resourceHolderToUse);
		Session session = null;
		try {
			boolean isExistingCon = (con != null);
			if (!isExistingCon) {
				con = resourceFactory.createConnection();
				resourceHolderToUse.addConnection(con);
			}
			session = resourceFactory.createSession(con);
			resourceHolderToUse.addSession(session, con);
			if (startConnection) {
				con.start();
			}
		}
		catch (JMSException ex) {
			if (session != null) {
				try {
					session.close();
				}
				catch (Throwable ex2) {
					// ignore
				}
			}
			if (con != null) {
				try {
					con.close();
				}
				catch (Throwable ex2) {
					// ignore
				}
			}
			throw ex;
		}
		if (resourceHolderToUse != resourceHolder) {
			TransactionSynchronizationManager.registerSynchronization(
					new JmsResourceSynchronization(
							connectionFactory, resourceHolderToUse, resourceFactory.isSynchedLocalTransactionAllowed()));
			resourceHolderToUse.setSynchronizedWithTransaction(true);
			TransactionSynchronizationManager.bindResource(connectionFactory, resourceHolderToUse);
		}
		return session;
	}


	/**
	 * Callback interface for resource creation.
	 * Serving as argument for the <code>doGetTransactionalSession</code> method.
	 */
	public interface ResourceFactory {

		/**
		 * Fetch an appropriate Session from the given JmsResourceHolder.
		 * @param holder the JmsResourceHolder
		 * @return an appropriate Session fetched from the holder,
		 * or <code>null</code> if none found
		 */
		Session getSession(JmsResourceHolder holder);

		/**
		 * Fetch an appropriate Connection from the given JmsResourceHolder.
		 * @param holder the JmsResourceHolder
		 * @return an appropriate Connection fetched from the holder,
		 * or <code>null</code> if none found
		 */
		Connection getConnection(JmsResourceHolder holder);

		/**
		 * Create a new JMS Connection for registration with a JmsResourceHolder.
		 * @return the new JMS Connection
		 * @throws JMSException if thrown by JMS API methods
		 */
		Connection createConnection() throws JMSException;

		/**
		 * Create a new JMS Session for registration with a JmsResourceHolder.
		 * @param con the JMS Connection to create a Session for
		 * @return the new JMS Session
		 * @throws JMSException if thrown by JMS API methods
		 */
		Session createSession(Connection con) throws JMSException;

		/**
		 * Return whether to allow for a local JMS transaction that is synchronized with
		 * a Spring-managed transaction (where the main transaction might be a JDBC-based
		 * one for a specific DataSource, for example), with the JMS transaction
		 * committing right after the main transaction.
		 * @return whether to allow for synchronizing a local JMS transaction
		 */
		boolean isSynchedLocalTransactionAllowed();
	}


	/**
	 * Callback for resource cleanup at the end of a non-native JMS transaction
	 * (e.g. when participating in a JtaTransactionManager transaction).
	 * @see org.springframework.transaction.jta.JtaTransactionManager
	 */
	private static class JmsResourceSynchronization extends TransactionSynchronizationAdapter {

		private final Object resourceKey;

		private final JmsResourceHolder resourceHolder;

		private final boolean transacted;

		private boolean holderActive = true;

		public JmsResourceSynchronization(Object resourceKey, JmsResourceHolder resourceHolder, boolean transacted) {
			this.resourceKey = resourceKey;
			this.resourceHolder = resourceHolder;
			this.transacted = transacted;
		}

		public void suspend() {
			if (this.holderActive) {
				TransactionSynchronizationManager.unbindResource(this.resourceKey);
			}
		}

		public void resume() {
			if (this.holderActive) {
				TransactionSynchronizationManager.bindResource(this.resourceKey, this.resourceHolder);
			}
		}

		public void beforeCompletion() {
			TransactionSynchronizationManager.unbindResource(this.resourceKey);
			this.holderActive = false;
			if (!this.transacted) {
				this.resourceHolder.closeAll();
			}
		}

		public void afterCommit() {
			if (this.transacted) {
				try {
					this.resourceHolder.commitAll();
				}
				catch (JMSException ex) {
					throw new SynchedLocalTransactionFailedException("Local JMS transaction failed to commit", ex);
				}
			}
		}

		public void afterCompletion(int status) {
			if (this.transacted) {
				this.resourceHolder.closeAll();
			}
		}
	}

}