Writing a URI Resolver for Output Files
Saxon also allows you to write an OutputURIResolver, which performs an
analogous role for URIs specified in the href attribute of
xsl:result-document.
This is therefore applicable to XSLT only. The
OutputURIResolver is called when writing of the output document starts, at
which point it must return a JAXP Result object to act as the output
destination. It is called again when writing of an output document is complete.
You can nominate an OutputURIResolver by calling
((Controller)transformer).setOutputURIResolver(new UserOutputResolver()),
or by calling factory.setAttribute("http://saxon.sf.net/feature/outputURIResolver",
new UserOutputResolver()).