Question

I’d like to write a MessageConverter class that can wrap another MessageConverter. This MessageConverter would call the child converter, which is assumed to generate a TextMessage. It would take the payload and GZIP compress it, creating a BytesMessage which is ultimately returned to the sender.

The problem is in writing fromMessage(). I can convert the payload back into the string, but then I want to create a ‘dummy’ TextMessage to stuff the string into to then pass to the child MessageConverter’s fromMessage() method. There I’m hitting a brick wall because I can’t create a TextMessage without a JMS session object, and it appears that there is no way at all to get a session in this context.

I could create additional properties to wire up more stuff to this class, but it doesn’t look like I can easily even obtain a session from a JMSTemplate object, and I can’t imagine what else I’d need to have.

I am on the verge of creating a private TextMessage implementation within this code just for the purpose of wrapping a string for the child MessageConverter. That class will require tons of dummy methods to flesh out the Interface, and all of that typing makes baby Jesus cry.

Can anyone suggest a better way?

Answer 1

So I did, in fact, make one of these:

    private static class FakeTextMessage implements TextMessage {             public FakeTextMessage(Message m) { this.childMessage = m; }             private String text;             private Message childMessage;             public void setText(String t) { this.text = t; }             public String getText() { return this.text; }              // All the rest of the methods are simply pass-through             // implementations of the rest of the interface, handing off to the child message.             public void acknowledge() throws JMSException { this.childMessage.acknowledge(); }             public void clearBody() throws JMSException { this.childMessage.clearBody(); }             public void clearProperties() throws JMSException { this.childMessage.clearProperties(); }             public Enumeration getPropertyNames() throws JMSException { return this.childMessage.getPropertyNames(); }             public boolean propertyExists(String pn) throws JMSException { return this.childMessage.propertyExists(pn); }              // and so on and so on     } 

Makes me long for Objective C. How is THAT possible? 🙂