What's wrong with doing it in XSLT?

See Mike Kay's post: if your DB access causes side effects, you
are in trouble.

My motive for not using
anything but XSLT and Java is simply a matter of consolidating
an unnecessary plethora of tools to depend on.

Sounds exactly like "Golden Hammer" to me. XSLT has its
strenghts but also weaknesses. I wouldn't write a C compiler
or orbital calculations with XSLT.