XOM API for Processing XML with Java

[Elliotte Rusty Harold <elharo AT metalab.unc.edu>]

> In d23, nu.xom.xerces.XML1_0ParserConfiguration throws exceptions 
> (see below) on older xerces versions such as xerces-2.3.0 because 
> certain methods or fields are missing there. It works fine with 
> xerces-2.6.1.
>
> One would hope that people have that latest xerces version, but in 
> servlet containers and other deployed middleware one cannot assume 
> that, because often the xerces version gets automatically 
> "inherited" from the whatever the container ships with. Since these 
> old xerces versions don't implement xml 1.1 anyway, I think xom 
> should silently ignore the exception with try-catch and just move on 
> undisturbed.

That's a reasonable idea. Let me see if I can implement it. You 
should note though, that every version of Xerces prior to 2.6.1 has 
noticeable bugs in XML parsing and other areas. It's completely 
possible you won't trip over any of those bugs, but it is something 
to be aware of.

Hmm, OK I looked at the problem. It's trickier than I thought. The 
XML1_0ParserConfiguration.parse method is not a no-op. It returns 
something, and  I'm not sure how to do that with an earlier version 
of Xerces. Possibly I need to check the Xerces version and only set 
the property in the first place if it's 2.5 or later or some such. 
(Does anyone happen to know the first version of Xerces to turn on 
XML 1.1 by default?) Or I may just have to work my way back through 
the Xerces CVS tree to see what the code looked like in 2.3. I'll add 
it to the TODO list. It may be a few a while before I can get to it 
though.
--

  Elliotte Rusty Harold
  elharo AT metalab.unc.edu
  Effective XML (Addison-Wesley, 2003)
  http://www.cafeconleche.org/books/effectivexml
  http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA