Question

I’m trying to use Spring AsyncServlet with Camel and ActiveMQ. I’m using the following versions.

    <spring.version>3.2.0.M1</spring.version>
    <camel.version>2.10.0</camel.version>
    <jetty.version>8.1.3.v20120416</jetty.version>
    <activemq.version>5.6.0</activemq.version>

I want to push messages to clients that are connected to the server (Jetty).

My Camel routes looks like the following.

from("mina:udp://source_machine:9998").to("activemq:myqueue");

I’ve the following in my Spring/Camel configuration based on this.

    <bean id="jmsConnectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
    <property name="brokerURL" value="vm://localhost:61616" />
</bean>

<bean id="pooledConnectionFactory" class="org.apache.activemq.pool.PooledConnectionFactory">
    <property name="maxConnections" value="8" />
    <property name="maximumActive" value="500" />
    <property name="connectionFactory" ref="jmsConnectionFactory" />
</bean>

<bean id="jmsConfig" class="org.apache.camel.component.jms.JmsConfiguration">
    <property name="connectionFactory" ref="pooledConnectionFactory" />
    <property name="transacted" value="false" />
    <property name="concurrentConsumers" value="10" />
</bean>

<bean id="activemq" class="org.apache.activemq.camel.component.ActiveMQComponent">
    <property name="configuration" ref="jmsConfig" />
</bean>

Using the above configuration I’m able to input messages into my queue (at least I don’t get any errors.) However, I’ve no idea how to read from this queue.

1. Is this the correct way of configuring ActiveMQ when using Spring, Camel and Jetty ?
2. How do I add/register a MessageListener javax.jms.MessageListener so that I can read from my queue.
3. How can I control the queue size and make the queue non-persistent?
4. It it possible to add multiple listeners

Thanks.

Answer 1

Your config looks good for activemq. No idea about jetty. There is no jetty config in the snippet you provided.

In a camel route you can simply use a from activemq endpoint to listen on the queue.

from(“activemq:myqueue”).to(“log:test”);

Btw. I typically use the jms ednpoint instead of the ActiveMQ one. This has the advantage that it is easier to switch to another jms provider if you have to at some point.

You can also use the connectionfactory and use you own DefaultMessageListenerContainer in a bean. See the spring configs for how to do this but this has nothing to do with camel then.

You can control the queue size in the activemq config. Using the http://activemq.apache.org/producer-flow-control.html.

You can not make a queue no persistent but you can define the messages you send to be non persistent. http://activemq.apache.org/how-do-i-disable-persistence.html

You can define many listeners and you can even define the number of threads for one listener using the option maxConcurrentConsumers on the from endpoint above.