[CAMEL-5055] Offer a way to not set a transaction manager in camel-jms

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.9.0
• Fix Version/s: 2.10.0
• Component/s: camel-activemq, camel-jms
• Labels: camel-jms transactions
• Estimated Complexity: Unknown
• Assignee: Babak Vahdat
• Reporter: Torsten Mielke
• Created: 29/Feb/12 14:54
• Updated: 01/Jun/12 13:07
• Resolved: 26/May/12 15:25

Description

The following sample Spring config sets up a camel-activemq component

<bean id="activemq" class="org.apache.activemq.camel.component.ActiveMQComponent"> 
     <property name="configuration" ref="jmsConfigAmq" />
  </bean>
  
  <bean id="jmsConfigAmq" class="org.apache.activemq.camel.component.ActiveMQConfiguration" >
      <property name="connectionFactory" ref="jmsPooledConnectionFactory" /> 
      <property name="transacted" value="true"/> 
      <!--  <property name="transactionManager" ref="jmsTransactionManager" />  -->
      <property name="cacheLevelName" value="CACHE_CONSUMER"/>
  </bean>
  
  <bean id="jmsTransactionManager" class="org.springframework.jms.connection.JmsTransactionManager">
    <property name="connectionFactory" ref="jmsPooledConnectionFactory" />
  </bean>           
     
  <bean id="jmsConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory"> 
    <property name="brokerURL" value="tcp://localhost:61617" /> 
    <property name="watchTopicAdvisories" value="false" />
  </bean>
	    
   <bean id="jmsPooledConnectionFactory" class="org.apache.activemq.pool.PooledConnectionFactory" >
      <property name="maxConnections" value="1"/>
      <property name="connectionFactory" ref="jmsConnectionFactory"/>
   </bean>

The ActiveMQConfiguration sets transacted=true and configures for a JmsTransactionManager. Also, a PooledConnectionFactory is used.
The config for a camel-jms component would be similar.

The Spring JMS javadoc on AbstractPollingMessageListenerContainer.setTransactionManager states:

Note: Consider the use of local JMS transactions instead. Simply switch the "sessionTransacted" flag to "true" in order to use a locally transacted JMS Session for the entire receive processing, including any Session operations performed by a SessionAwareMessageListener (e.g. sending a response message).

It basically advises to only set transacted=true and don't specify a TX manager. The benefit of doing so is that the cacheLevel setting will be honored when using local transactions without a configured TX manager. When a TX manager is configured, no caching happens at DMLC level and its necessary to rely on a pooled connection factory. This is discussed here.

However right now its not possible to configure the cameljms or camel-activemq component to not use an external TX manager when transacted=true is set.
Even when setting lazyCreateTransactionManager=false.
In case of camel-activemq, it still creates a default JmsTransactionManager:

ActiveMQConfiguration.java

public PlatformTransactionManager getTransactionManager() {
  PlatformTransactionManager answer = super.getTransactionManager();
  if (isTransacted() && answer == null) {
    // lets auto-default the transaction manager if its not specified
    answer = createTransactionManager();
    setTransactionManager(answer);
    answer = getTransactionManager();
  }
  return answer;
}

In case of camel-jms it throws an exception:

JmsConfiguration.java

PlatformTransactionManager tm = getTransactionManager();
if (tm != null) {
  container.setTransactionManager(tm);
} else if (transacted) {
  throw new IllegalArgumentException("Property transacted is enabled but a transactionManager was not injected!");
}

We should allow for using transactions in camel-jms and camel-activemq without setting an external TX manager.

Issue Links

• relates to: AMQ-3861 Offer a way to not set a transaction manager in activemq-camel