RE: Compelling use case for XML Catalogs?

Hi Folks,

Does XML Catalog have the ability to express this:

    If the DOCTYPE doesn't use one of these three URLs:

        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd 
        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd
        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd 

   then trigger an error?

Alternatively, perhaps it has the ability to express this: 

    If the DOCTYPE doesn't use one of these three URLs:

        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd   
        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd 
        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd  

   then use this default DTD: 

        - http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd 

Does XML Catalog have either of these capabilities? 

If it does not, how would you avoid a spoofing attack? 

    Spoofing attack: a bad person creates an XHTML document
    that is invalid; to avoid being rejected the DOCTYPE references 
    a DTD, created by the bad person, that accepts the bad XHTML 
    document.

Would you need to supplement XML Catalog with another tool, which checks that XML Catalog processing has resulted in all URLs being appropriately mapped?

/Roger