Create a Message Driven Bean (MDB) and stand alone client

Next example is a message driven bean deployed on glassfish that gets called by a stand alone client. Let start with creating the JMS Connection Factory and the JMS Queue on glassfish.

Issue the following statement to create the connection factory:

asadmin create-jms-resource –restype javax.jms.ConnectionFactory jms/ConnectionFactory

After this create the resource destination:

asadmin create-jmsdest -T queue sampleQueue

Create the JMS destination:

asadmin create-jms-resource –restype javax.jms.Queue –property Name=sampleQueue jms/SampleQueue

Now we can create the Message Driven Bean:

broersa@debian1:~/work/HelloApp/HelloMDB/src/com/bekijkhet$ cat HelloMDB.java

package com.bekijkhet;
import javax.ejb.MessageDriven;
import javax.jms.MessageListener;
import javax.jms.Message;
import javax.jms.TextMessage;

@MessageDriven(mappedName="jms/SampleQueue")
public class HelloMDB implements MessageListener {

    public void onMessage(Message msg) {
      try {
        if (msg instanceof TextMessage) {
          TextMessage txtmsg = (TextMessage) msg;
          System.out.println("Got message: "+txtmsg.getText());
        }
      } catch (Exception e) { System.out.println(e.toString()); }
    }

}

broersa@debian1:~/work/HelloApp/HelloMDB$ cat build.xml

<project name="HelloMDB" default="dist" basedir=".">
    <description>
        simple example build file
    </description>
  <!-- set global properties for this build -->
  <property name="src" location="src"/>
  <property name="build" location="build"/>
  <property name="dist"  location="dist"/>

  <target name="init">
    <!-- Create the time stamp -->
    <tstamp/>
    <!-- Create the build directory structure used by compile -->
    <mkdir dir="${build}"/>
  </target>

  <target name="compile" depends="init"
        description="compile the source " >
    <!-- Compile the java code from ${src} into ${build} -->
    <javac srcdir="${src}" destdir="${build}"/>
  </target>

  <target name="dist" depends="compile"
        description="generate the distribution" >
    <!-- Create the distribution directory -->
    <mkdir dir="${dist}"/>

    <!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
    <jar jarfile="${dist}/HelloMDB.jar" basedir="${build}"/>
  </target>

  <target name="clean"
        description="clean up" >
    <!-- Delete the ${build} and ${dist} directory trees -->
    <delete dir="${build}"/>
    <delete dir="${dist}"/>
  </target>
</project>

Build and deploy the MDB:asant dist

asadmin deploy dist/HelloMDB.jar

Let’s go on creating the stand alone client to call the MDB.

broersa@debian1:~/work/HelloApp/HelloClient/src/com/bekijkhet/helloclient$ cat HelloMDBClient.java

package com.bekijkhet.helloclient;
import javax.naming.*;
import javax.jms.*;

public class HelloMDBClient {
  public static void main(String args[]) {
    try {
      // will get the local default context from appserv-rt.jar
      Context ctx = new InitialContext();
      ConnectionFactory connectionFactory = (ConnectionFactory)ctx.lookup("jms/ConnectionFactory");
      Queue queue = (Queue)ctx.lookup("jms/SampleQueue");
      javax.jms.Connection connection = connectionFactory.createConnection();
      javax.jms.Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);
      MessageProducer messageProducer = session.createProducer(queue);
      TextMessage message = session.createTextMessage();
      message.setText("my own text message");
      System.out.println( "Send: "+ message.getText());
      messageProducer.send(message);
      connection.close();
    } catch (Exception e) {System.out.println(e.toString());}
  }
}

Compile and run:

javac -cp $GLASSFISH_HOME/lib/appserv-rt.jar:$GLASSFISH_HOME/lib/javaee.jar:. -d . HelloMDBClient.java

java -cp $GLASSFISH_HOME/lib/appserv-rt.jar:$GLASSFISH_HOME/lib/javaee.jar:$GLASSFISH_HOME/lib/install/applications/jmsra/imqjmsra.jar:$GLASSFISH_HOME/lib/appserv-admin.jar:. com.bekijkhet.helloclient.HelloMDBClient

<snipped a lot of initialisation output..>

Send: my own text message

When we look at the server log file ($GLASSFISH_HOME/domains/domain1/logs/server.log) we can see the MDB got fired:

[#|2007-11-23T12:17:45.309+0100|INFO|sun-appserver9.1|javax.enterprise.system.stream.out|_ThreadID=23;_ThreadName=p: thread-pool-1; w: 34;|
Got message: my own text message|#]
After this my client app (HelloMDBClient) hangs….. Press ctrl-c to end the process. I can’t find a solution to get the program exit normally… It looks like another thread got starten to listen for incomming messages??

In the next sample I create an EJB to send messages which will be run from inside the container. This seams to work without hanging. Maybe someone can explain?

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