XOM API for Processing XML with Java

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

Luke Weese wrote:

> I have put together a help system based on Docbook XML, with a couple
> of nasty requirements that are causing me trouble. These are XML
> catalogs and XInclude support. I have had this working with libxml's
> xmllint utility, but the need has arisen for a Java-based replacement.
> XOM seems to be the only java API that supports XInclude with the
> XPointer attribute, but alas, catalogs are not supported. I have
> searched the list and found some instructions on using Apache's (Norm
> Walsh's) ResolvingXMLReader to plug in catalog support, but I am
> getting errors I do not understand.

Catalog support is on the TODO list, but probably not for 1.1. See 
http://www-128.ibm.com/developerworks/xml/library/x-mxd3.html

> First, I'll explain my need for catalog support and how it relates to
> XInclude. This is a sample line from an XML document:
>
> <xi:include xmlns:xi="http://www.w3.org/2001/XInclude";
> href="file:///fw/generic/genericText.xml"
> xpointer="genericText_editKeyField" >
>
> As you can see, the "href" attribute is not a valid url. With xmllint,
> I used an XML catalog to rewrite the URI to a local file, like this:

What's wrong with it? It looks syntactically correct to me. Does it just 
point to the wrong place?


>   // srcFile is the XML file
>   System.setProperty("xml.catalog.files", 
> "/home/pulse/core/help/catalog.xml");
>   XMLReader parser = new org.apache.xml.resolver.tools.ResolvingXMLReader();
>   nu.xom.Builder builder = new nu.xom.Builder(parser);
>   nu.xom.Document input = builder.build(srcFile.getAbsolutePath());
>
> builder.build throws a ParserException with the following message:
> -- nu.xom.ParsingException: Additional namespace
> http://www.w3.org/2001/XInclude conflicts with existing namespace
> binding. at line -1, column -1.

I don't know what's going on here either. It's possible 
ResolvingXMLReader is buggy and misreporting namespaces. It wouldn't be 
the first bug XOM uncovered in ResolvingXMLReader. It would help if 
there were a reasonably self-contained test case that could be debugged.

--
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