CODEWITHSUNDEEP
javaobjectjmsmessagepojo
Moonlit
Moonlit

Reputation: 5419

Receiving Java Objects over JMS

Is this really the way to receive POJOs with JMS?

public void onMessage(Message msg) {
     ObjectMessage objMsg = (ObjectMessage) msg;
     if(objMsg.getObject() instanceof <<sometype>>) {
        //do something 
     }
 }

Do I have to cast to ObjectMessage. Actually then i have to check if msg is castable to ObjectMessage too.

or do i miss something?

thx

Upvotes: 4

Views: 9764

Answers (3)

Petter Nordlander
Petter Nordlander

Reputation: 22279

Yes, and you might want to check some exceptions. However with spring (and Frameworks such as apache camel) you could rather easily wire up a bean that simply processes objects of some class. That might or might not be worth the overhead and added complexity of configuration to simplify the code.

Look a few pages into this article for a description: http://www.wmrichards.com/mdp.pdf

Upvotes: 1

JB Nizet
JB Nizet

Reputation: 692121

AFAIK, that's it. It's pretty rare to mix different message types, and different object types inside the message, in a single destination (queue or topic), though. So you might skip the instanceof checks if you know that only ObjectMessages containing SomeType objects are expected.

Upvotes: 1

Rachel
Rachel

Reputation: 103567

Quoting example from JMS Spring Doc, as you can see from example, we need to check if message is of TextMessage type or not and so similarly in your case we have to check for casting or check for whether your object is instance of message type, so you have two approaches for it, hope this clarifies your issue.

Example

import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

public class ExampleListener implements MessageListener {

    public void onMessage(Message message) {
        if (message instanceof TextMessage) {
            try {
                System.out.println(((TextMessage) message).getText());
            }
            catch (JMSException ex) {
                throw new RuntimeException(ex);
            }
        }
        else {
            throw new IllegalArgumentException("Message must be of type TextMessage");
        }
    }
}

Upvotes: 1

Related Questions