[jdom-interest] JDom&DTD

[NP]

Hi all!
I've written a XML database, but now i have the need to validate it. For 
example this XML must have one tag (and only one) called <name>. So i 
can write a dtd grammar to do this work.
But my necessity is that when i parse the xml file (with jdom's -better, 
sax's- functions, like SAXBuilder.build) with duplicate TAG <name>, 
there is an exception that alerts this situation.

How I can resolve this problem?
(My fear is to write a by hand (and raw) function that works like i want...)

Thanks!