>>I'm not a great fan of picking things up by virtue of the fact that you find
>>them lying around on the classpath. That leads to a lot of the problems one
>>sees with the JAXP factory mechanism. It's expensive to search a large
>>classpath, and the results aren't always easily predictable, because many
>>environments create the classpath for themselves without giving you much
>>control. Saxon works this way with "known" external object models such as
>>JDOM and DOM4J - if the support module can be loaded, then it is used; but
>>for "unknown" user-defined models, you have to register it with the
>>I think what you are looking for is a kind of "meta-URI-resolver", which is
>>registered to Saxon as "the" URIResolver, but which actually delegates the
>>work to subsidiary resolvers based say on the URI scheme. That shouldn't
>>need any Saxon changes.
>>Michael Kay


I agree that you don't need to change Saxon to get a meta-URI-resolver to work when you are starting from scratch.

But I'm thinking about the case where you have a system in place already, with Saxon and some application that uses Saxon, and you want to add an ad-hoc resolver to it to retrieve from your favourite repository via an ad-hoc protocol.  You'll have to change some code bindings in the existing system in order to add the new resolver.  In one case that I am looking at, Saxon's StandardURIResolver looked like it would be a candidate for adding a new protocol because easier to modify than chasing down all of the places that the legacy application added URIResolvers to Configuration.

But I won't belabour the question.  Thanks for your advice and cheers.

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