Can transformations add/change the DOCTYPE?

Using java's JAXP 1.1.0

I am not familiar with transformations at all but

Can a transformation be use to insert a DOCTYPE if not found in the xml
file?

Some of my files will have a DOCTYPE and some won't

The size of my files is big. Could be as big as 32k lines so I think SAX
instead of DOM is a must.


I posted related questions about this problem but the ideas I got required
some freeware or shareware
but that is not acceptable in my company because of the licensing issues.
So I was wondering it transformations can be used for this


Does anyone