>For the moment, the DTM is not updatable.
DTM is not intended to be mutable; that's part of the performance/storage tradeoff we accepted in switching to this API. For now, the right answer is to let Xalan build a new DTM for your altered document. That isn't a lot of work for the programmer -- just pass in a DOMSource and let Xalan do the right thing for you automatically -- but it does mean we've given up efficiency in repeatedly processing similar documents in order to gain efficiency when processing documents we don't know are similar. I don't think we have any plans to change this design point at this time. > Or maybe it could be interesting to propose several implementations of > XPATH, one for the DTM and the other for DOM? Maintaining these two versions would be a _LOT_ of work, which is why we went with the solution of presenting the DOM via a DOM2DTM wrapper -- that hides the difference from the rest of the code. If you really need a mutable source document, the best solution I can come up with would be to write a data model which simultaneously implements DTM and the DOM APIs -- essentially, take DOM2DTM and integrate it back into a DOM tree. Could be done, but it'd be a significant programming investment.
