Entity resolution vs. URI resolution

Hi, this posting is regarding an issue that was discussed on the
sax-devel list recently, but I think it deserves a larger audience since
it is not specific to SAX.

In SAX there is an entity resolver that takes a pair (publicID,
systemID) as input:
  InputSource resolveEntity(String publicID, String systemID)

For other standards (such as W3C XML Schema), there is a need to resolve
a schema location URI as a single input paramater:
  InputSource resolveURI(String locationURI)

One view is that "entity resolution" = "uri resolution" + "publicID
resolution".  So if only "uri resolution" is desired, pass "null" as the
publicID.

Another view is that these are two fundamentally different animals and
so two different resolvers should be used.

So should entity resolution and URI resolution go through the same
resolver or different ones?

I hope I captured the essence of the argument.  If not, please correct
me.

-Edwin