users@jaxb.java.net

What's a good Patern for the following?

From: John Smith <java.dev.mtl_at_gmail.com>
Date: Tue, 25 Oct 2011 16:11:49 -0400

Say i have the following model

class PET
{
     name
     age
}

And I want to create a veterinerean REST service where you can register it
for checkup or operation or what ever.

So I have the following XML

<VET>
     <Username>
     <Passowrd>
     <Pet>
</VET>

Whats the Best way to represent this as a model?

class Vet
{
    username
    password
    pet
}

Now that's just an example...

Say I was creating a REST service for a general interface that gives access
to various services...

I want the base XML to be...

<Services>
    <Username>
    <Password>
    Service specific XML here?
</Services>

Is there a specific pattern to this?