BlazeDS + JMS + ActiveMQ

http://www.joshuaostrom.com/2008/08/01/tunkey-blazeds-jms-activemq/
I spent some time this week with BlazeDS and JMS. I wanted to integrate a Flex RIA with some [existing] backend Java classes. One goal was to interface the two in a loosely coupled fashion, enter Java Message Service (JMS).

The RIA uses a mx:producer to publish messages to a JMS topic which the backend Java class is listening in on [consuming] elsewhere in the enterprise. I used an ‘external install’ of ActiveMQ.

I downloaded the turnkey BlazeDS server to get things rolling.

I came across a few great posts in looking into this…

【Michael Martin’s Simplified BlazeDS and JMS】
http://mmartinsoftware.blogspot.com/2008/05/simplified-blazeds-and-jms.html

Christophe Coenraets
【Flex and JMS: Portfolio Viewer (LCDS jRun)】
http://coenraets.org/blog/2006/06/flex-and-jms-portfolio-viewer-updated-for-flex-2-ga/
【30 Minutes Flex Test-Drive for Java Developers (FDS)】
http://coenraets.org/blog/30-minutes-flex-test-drive-for-java-developers/

To be helpful, I’ve included some error messages and their causes:

Flex Runtime Error:
There was an unhandled failure on the server. MessageClient has been invalidated.
Cause: ActiveMQ not running.

Flex Runtime Error:
Client.Message.Encoding
Type ‘com.dl.samples.PersonVO’ not found.
Cannot create class of type ‘com.dl.samples.PersonVO’.
Cause: Java classes not on server.

Java Runtime Error
javax.naming.NameNotFoundException: messageTopic
at org.apache.activemq.jndi.ReadOnlyContext.lookup(ReadOnlyContext.java:225)
at javax.naming.InitialContext.lookup(Unknown Source)
at Chat.(Chat.java:55)
at Chat.main(Chat.java:27)
Cause: jndi.properties not present for java class

Java Runtime [BlazeDS] Error
[BlazeDS] JMS consumer for JMS destination ‘[destinationName]’ is being removed from the JMS adapter due to the following error: Name jms is not bound in this Context
[BlazeDS] JMS consumer for JMS destination ‘[destinationName]’ is stopping.
[BlazeDS] The corresponding MessageClient for JMS consumer for JMS destination ‘[destinationName]’ is being invalidated

Cause: context.xml Resource names do not match messaging-config.xml connection-factory / destination-jndi-name tags. (i.e. the ‘org.apache.activemq.ActiveMQConnectionFactory’ resource name in context.xml should match the connection-factory value in messaging-config and the ‘org.apache.activemq.command.ActiveMQTopic’ resource name in context.xml should match the destination-jndi-name value in messaging-config).

Adding the logging pattern ‘Service.Message.JMS’ to your services-config.xml can be very helpful in debugging BlazeDS JMS problems.

Here are the config files

C:/blazeds/tomcat/webapps/MyApp/WEB-INF/flex/services-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<services-config>
<services>
<service-include file-path="messaging-config.xml" />
</services>
<security/>
<channels>
<channel-definition id="my-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://localhost:8400/BlazeTest/messagebroker/amf" class="flex.messaging.endpoints.AMFEndpoint"/>
</channel-definition>
</channels>
<logging>
<target class="flex.messaging.log.ConsoleTarget" level="Debug">
<properties>
<prefix>[BlazeDS] </prefix>
<includeDate>false</includeDate>
<includeTime>false</includeTime>
<includeLevel>false</includeLevel>
<includeCategory>false</includeCategory>
</properties>
<filters>
<pattern>Endpoint.*</pattern>
<pattern>Service.*</pattern>
<pattern>Configuration</pattern>
<pattern>Service.Message.JMS</pattern>
</filters>
</target>
</logging>
</services-config>


C:/blazeds/tomcat/webapps/MyApp/WEB-INF/flex/messaging-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<service id="message-service" class="flex.messaging.services.MessageService">
<adapters>
<adapter-definition id="actionscript" class="flex.messaging.services.messaging.adapters.ActionScriptAdapter" default="true" />
<adapter-definition id="jms" class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
<default-channels>
<channel ref="my-amf"/>
</default-channels>
<destination id="simpleJMS">
<properties>
<jms>
<destination-type>Topic</destination-type>
<!--<message-type>javax.jms.TextMessage</message-type>-->
<message-type>javax.jms.ObjectMessage</message-type>
<connection-factory>java:comp/env/TopicConnectionFactory</connection-factory>
<destination-jndi-name>java:comp/env/messageTopic</destination-jndi-name>
<delivery-mode>NON_PERSISTENT</delivery-mode>
<message-priority>DEFAULT_PRIORITY</message-priority>
<acknowledge-mode>AUTO_ACKNOWLEDGE</acknowledge-mode>
<initial-context-environment>
<property>
<name>Context.INITIAL_CONTEXT_FACTORY</name>
<value>org.apache.activemq.jndi.ActiveMQInitialContextFactory</value>
</property>
<property>
<name>Context.PROVIDER_URL</name>
<value>tcp://localhost:61616</value>
</property>
</initial-context-environment>
</jms>
</properties>
<channels>
<channel ref="my-amf"/>
</channels>
<adapter ref="jms"/>
</destination>
</service>


C:/blazeds/tomcat/webapps/MyApp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>BlazeDS</display-name>
<description>BlazeDS Application</description>
<!-- Http Flex Session attribute and binding listener support -->
<listener>
<listener-class>flex.messaging.HttpFlexSession</listener-class>
</listener>
<!-- MessageBroker Servlet -->
<servlet>
<servlet-name>MessageBrokerServlet</servlet-name>
<display-name>MessageBrokerServlet</display-name>
<servlet-class>flex.messaging.MessageBrokerServlet</servlet-class>
<init-param>
<param-name>services.configuration.file</param-name>
<param-value>/WEB-INF/flex/services-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MessageBrokerServlet</servlet-name>
<url-pattern>/messagebroker/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>


C:/blazeds/tomcat/webapps/MyApp/META-INF/context.xml

<?xml version="1.0" encoding="UTF-8"?>
<Context path="/BlazeTest">
<Resource name="TopicConnectionFactory"
type="org.apache.activemq.ActiveMQConnectionFactory"
description="JMS Connection Factory"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
brokerURL="tcp://localhost:61616"
brokerName="myBroker"/>
<Resource name="messageTopic"
type="org.apache.activemq.command.ActiveMQTopic"
description="a simple topic"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
physicalName="messageTopic"/>
</Context>


Using the above messaging-config’s destination the message will come across as an ObjectMessage in Java.