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Transaction Oriented Endpoints (Camel Toes) like JMS support using a transaction for both inbound and outbound message exchanges. Endpoints that support transactions will participate in the current transaction context that they are called from.

You should use the SpringRouteBuilder to setup the routes since you will need to setup the spring context with the TransactionTemplates that will define the transaction manager configuration and policies.

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   // Send to bar in a new transaction
   from("activemq:queue:foo").policy(requirenew).to("activemq:queue:bar");

   // Send to bar without a transaction.
   from("activemq:queue:foo").policy(notsupported ).to("activemq:queue:bar");

Camel 1.x - Database Sample

In this sample we want to ensure that two endpoints is under transaction control. These two endpoints inserts data into a database.
The sample is in its full as a unit test.

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{snippet:id=e4|lang=java|url=camel/trunk/components/camel-spring/src/test/java/org/apache/camel/spring/interceptor/TransactionalClientDataSourceTest.java}

Camel 1.x - JMS Sample

In this sample we want to listen for messages on a queue and process the messages with our business logic java code and send them along. Since its based on a unit test the destination is a mock endpoint.

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{snippet:id=e1|lang=java|url=camel/trunk/components/camel-jms/src/test/java/org/apache/camel/component/jms/tx/JMSTransactionalClientTest.java}

Camel 1.x - Spring based configuration

In Camel 1.4 we have introduced the concept of configuration of the error handlers using spring XML configuration. The sample below demonstrates that you can configure transaction error handlers in Spring XML as spring beans. These can then be set as global, per route based or per policy based error handler. The latter has been demonstrated in the samples above. This sample is the database sample configured in Spring XML.

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We strongly recommend that you configure the backing system for correct redelivery policy in your environment.

Camel 2.0 - Database Sample

In this sample we want to ensure that two endpoints is under transaction control. These two endpoints inserts data into a database.
The sample is in its full as a unit test.

First of all we setup the usual spring stuff in its configuration file. Here we have defined a DataSource to the HSQLDB and a most importantly
the Spring DataSoruce TransactionManager that is doing the heavy lifting of ensuring our transactional policies. You are of course free to use any
of the Spring based TransactionMananger, eg. if you are in a full blown J2EE container you could use JTA or the WebLogic or WebSphere specific managers.

As we use the new convention over configuration we do not need to configure a transaction policy bean, so we do not have any PROPAGATION_REQUIRED beans.
All the beans needed to be configured is standard Spring beans only, eg. there are no Camel specific configuration at all.

{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/interceptor/springTransactionalClientDataSourceMinimalConfiguration.xml}

Then we are ready to define our Camel routes. We have two routes: 1 for success conditions, and 1 for a forced rollback condition.
This is after all based on a unit test. Notice that we mark each route as transacted using the transacted tag.

{snippet:id=e2|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/interceptor/springTransactionalClientDataSourceMinimalConfiguration.xml}

That is all that is needed to configure a Camel route as being transacted. Just remember to use the transacted DSL. The rest is standard Spring XML to setup the transaction manager.

See Also

• JMS
• Dead Letter Channel
• Error Handler

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