XOM API for Processing XML with Java

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

Wolfgang Hoschek wrote:
> It may have fixed some case, but unfortunately not mine.
> The external entity used reads as follows
>
> [hoschek /testsuite] cat copy/ent21.xml
> <?xml version="1.0" encoding="UTF-8" ?>
> <extEnt attr="x"><sub2>z</sub2></extEnt>

OK. I've looked at it more closely. I think what's happening is that 
your code depends on a bug that I've now fixed. For a while when 
reporting relative URLs found in external ENTITY declarations, some SAX 
parsers including Xerces simply passed them on as is. Others including 
Crimson absolutized them. That is a URL such as data.xml might or might 
not get changed to something like file:///Users/elharo/tests/data.xml. I 
was primarily using a parser that did not absolutize them, and I suspect 
you were using a parser that did.

Starting with SAX 2.0.2, the SAX spec made it clear that parsers were 
expected to fully absolutize all URLs. Xerces implemented this behavior 
around 2.7 or 2.7.1. However, Crimson always did this; and I suspect you 
were using Crimson.

However I don't want XOM to do that. I expect XOM to maintain the 
original internal DTD subset, relative URLs and all, to the maximum 
extent possible. When I noticed Xerces had changed its behavior I wrote 
a workaround for Xerces that restored the original relative URLs. The 
same code is what I think broke your tests with Crimson.

If you want BNUX to be a self-contained data format, then you really 
could avoid external entity declarations completely. There's not a lot 
of need to include them. If you do include them, then the data is really 
not self-contained. You might even want to get rid of the DOCTYPE. A 
document with a DOCTYPE and anything beyond the internal DTD subset is 
really not self-contained.

If anyone would like to make a case that XOM should absolutize relative 
URLs found in the internal DTD subset, go ahead. There are arguments on 
both sides of this. My gut is that absolutizing relative URLs on a round 
trip is wrong since it can point the declarations at a different host as 
the document is moved. However, there are reasons to absolutize them as 
well which is why SAX settled on this behavior as the default.

--
Elliotte Rusty Harold  elharo AT metalab.unc.edu
XML in a Nutshell 3rd Edition Just Published!
http://www.cafeconleche.org/books/xian3/
http://www.amazon.com/exec/obidos/ISBN=0596007647/cafeaulaitA/ref=nosim