> However, so far I'm writing the result documents to a folder 
> in the filesystem. As I'm planing to package them into ePub 
> file using java.util.zip, this is probably not very smart. Is 
> there a way to avoid serializing to files and pass the result 
> documents directly to java.util.zip, probably as streams? I 
> saw OutputURIResolver mentioned, but couldn't find a decent example.
> 

If you're using Saxon then you should certainly be able to do this with the
OutputURIResolver, but I can't point you to an example that shows it being
used this way. But I'm not sure why you are finding it difficult.

In your resolve() method, create a StreamResult whose OutputStream is a
ZipOutputStream, and in your close() method, close that stream.

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay