XOM API for Processing XML with Java

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

I have posted what I hope is XOM 1.0 alpha 1 at the usual location:

http://cafeconleche.org/XOM/

Assuming nobody finds any gross flaws in the packaging (e.g. missing 
classes, etc.) I'll announce this more broadly tomorrow.

This is a very significant milestone for XOM. There have been *no* 
API level changes since the previous release (1.0d25) and I do not 
foresee any backwards incompatible API changes in the future. From 
this point forward, any changes to the API will require some fairly 
hefty justification, not just my usual "Hmm, this method name is a 
little more obvious than that method name." Code written to 1.0a1 
should be able to run without recompilation for the foreseeable 
future.

There may of course still be bugs. There are definitely a couple of 
sticky places in the code I need to look at before I declare beta 1, 
but the API is pretty much set at this point.

Changes since 1.0d25 include:

    * XOM now fully supports the 2nd candidate recommendation syntax 
for XInclude; including preservation of xml:lang values.

    *  The base URI handling has been modified as follows:
         1. getBaseURI() always returns an absolute URI or the empty 
string if the base URI is not known. Other than the empty string it 
never returns a relative URI. It never returns null.
         2. The base URI of an element does not change when it is 
detached or copied.
         3. The setBaseURI() method only accepts an absolute URI. It 
throws a MalformedURIException if you attempt to pass it a relative 
URI, or a URI with a fragment identifier. (Relative URIs are still 
allowed in xml:base attributes.)

   * XOM will not double verify when being fed data through the 
Apache XML Commons catalog filter; provided that the underlying 
parser is good.

   * Constraints on parentage are not checked when building with 
NonVerifyingFactory.

   * DOMConverter and several methods have been rewritten with 
non-recursive algorithms. Some work remains to be done in this area, 
however.

There appear to be some bugs in Sun's JDK 1.4.2_03 that break about 5 
or 6 of the unit tests. All tests pass with JDK 1.4.2_02 and JDK 
1.5.0a1. Ant 1.5.x is required to build XOM. I have been unable to 
get the tests to run with Ant 1.6, and the Ant developers seem 
actively hostile to any reports about this issue.

I have not yet resolved some of the class loader issues reported by 
various people. I'd appreciate it if anyone who's encountered a 
problem with XOM when used in TomCat or other multi-classloader 
environments let me know if the problem still occurs with the latest 
release. If it does, let me know and fixing that will be the highest 
priority for alpha 2.

If nobody spots any show stopping problems, I'll announce this on 
Cafe con Leche tomorrow or Thursday.

--

  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