DTD Parsing with xerces

Hi All,
I was trying to use XERCES for parsing a DTD document. There seems to be 
more than one way to accomplish the above. For my purpose, I was able to 
extend the org.apache.xerces.parsers.DOMParser class and override the DTD 
associated methods, but these do not provide the advanced features as 
those provided by org.apache.xerces.parsers.DTDParser. Does any know a way 
of how one could use org.apache.xerces.parsers.DTDParser class? Any Sample 
code?
Regards,
Vijay