7.3. Sample JMS XA Configuration
Spring XML configuration
Example 7.1, “Camel JMS Component with XA Enabled” shows the complete Blueprint XML configuration required to initialize the
jmstx Camel JMS component with XA transactions. After setting up the Camel JMS component with this code, you can create a transactional JMS endpoint in a route using a URL like jmstx:queue:QueueName.
Example 7.1. Camel JMS Component with XA Enabled
<?xml version="1.0" encoding="UTF-8"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<!--
OSGi TM Service
-->
<!-- access through Spring's PlatformTransactionManager -->
<reference id="osgiPlatformTransactionManager"
interface="org.springframework.transaction.PlatformTransactionManager"/> 1
<!-- access through PlatformTransactionManager -->
<reference id="osgiJtaTransactionManager"
interface="javax.transaction.TransactionManager"/> 2
...
<!--
JMS TX endpoint configuration
-->
<bean id="jmstx"
class="org.apache.activemq.camel.component.ActiveMQComponent"> 3
<property name="configuration" ref="jmsTxConfig" />
</bean>
<bean id="jmsTxConfig"
class="org.apache.camel.component.jms.JmsConfiguration"> 4
<property name="connectionFactory" ref="jmsXaPoolConnectionFactory"/>
<property name="transactionManager" ref="osgiPlatformTransactionManager"/>
<property name="transacted" value="false"/>
<property name="cacheLevelName" value="CACHE_CONNECTION"/>
</bean>
<!-- connection factory wrapper to support auto-enlisting of XA resource -->
<bean id="jmsXaPoolConnectionFactory"
class="org.apache.activemq.pool.JcaPooledConnectionFactory"> 5
<property name="name" value="MyXaResourceName" />
<property name="maxConnections" value="1" /> 6
<property name="connectionFactory" ref="jmsXaConnectionFactory" />
<property name="transactionManager" ref="osgiJtaTransactionManager" />
</bean>
<bean id="jmsXaConnectionFactory"
class="org.apache.activemq.ActiveMQXAConnectionFactory"> 7
<property name="brokerURL" value="vm:local"/> 8
<property name="userName" value="UserName"/>
<property name="password" value="Password"/>
<property name="redeliveryPolicy"> 9
<bean class="org.apache.activemq.RedeliveryPolicy">
<property name="maximumRedeliveries" value="0"/>
</bean>
</property>
</bean>
<!--
ActiveMQ XA Resource Manager
-->
<bean id="resourceManager"
class="org.apache.activemq.pool.ActiveMQResourceManager"
init-method="recoverResource">
<property name="transactionManager" ref="osgiJtaTransactionManager" />
<property name="connectionFactory" ref="jmsXaPoolConnectionFactory" />
<property name="resourceName" value="activemq.default" /> 10
</bean>
...
</blueprint>Listing notes
The preceding Spring XML configuration can be explained as follows:
- 1
- Define a reference to the OSGi service that exposes the
PlatformTransactionManagerinterface of the OSGi container's built-in XA transaction manager. This service can then be accessed through the bean ID,osgiPlatformTransactionManager. - 2
- Define a reference to the OSGi service that exposes the JTA
TransactionManagerinterface of the OSGi container's built-in XA transaction manager. This service can then be accessed through the bean ID,osgiJtaTransactionManager. - 3
- The bean identified by the ID,
jmstx, is the ActiveMQ implementation of the Camel JMS component. You can use this component to define transactional JMS endpoints in your routes. The only property that you need to set on this bean is a reference to theJmsConfigurationbean with the ID,jmsTxConfig. - 4
- The
JmsConfigurationbean with the ID,jmsTxConfig, is configured as described in Section 7.1, “Enabling XA on the Camel JMS Component”. In particular, the configuration bean gets a reference to the XA pooled connection factory and a reference to theosgiPlatformTransactionManagerbean. The transacted property must be set tofalse. - 5
- The
JcaPooledConnectionFactoryis a wrapper class that adds extra capabilities to the basic connection factory bean (that is, it adds the capabilities to auto-enlist XA resources and to pool JMS connections). - 6
- The
maxConnectionsproperty should be set to 1. - 7
- The bean with the ID,
jmsXaConnectionFactory, is the basic connection factory, which encapsulates the code for connecting to the JMS broker. In this case, the bean is an instance ofActiveMQXAConnectionFactorytype, which is a special connection factory class that you must use when you want to connect to the ActiveMQ broker with support for XA transactions. - 8
- The
brokerURLproperty defines the protocol for connecting to the broker. In this case, thevm:localURL connects to the broker that is embedded in the current JVM and is identified by the namelocal(the configuration of the embedded broker is not shown in this example).There are many different protocols supported by Apache ActiveMQ that you could use here. For example, to connect to a remote broker through the OpenWire TCP protocol listening on IP port61616on hostMyHost, you would use the broker URL,tcp://MyHost:61616. - 9
- In this example, the redelivery policy is disabled by setting
maximumRedeliveriesto0. Typically, you would not use a redelivery policy together with transactions. An alternative approach would be to define an exception handler that routes failed exchanges to a dead letter queue. - 10
- The
resourceNameproperty is the key entry that maps from the transaction manager log to a real-worldXAResourceobject. It must be unique for eachXAResourceobject.
