XOM API for Processing XML with Java

["Michael McEniry" <mmceniry AT itsc.uah.edu>]

Title: RE: [XOM-interest] Base URIs

Elliotte Rusty Harold wrote:
> I am exploring the API for base URLs. My current thinking is that there

Is your notion of a base URI distinct from the XML Base
(http://www.w3.org/TR/xmlbase/) recommendation? If so,
what does the value of a base URI mean?

It seems reasonable for XOM to understand base URIs,
since more and more standards seem to be assuming they
exist. Will XOM grow to support XLink?

> will be two methods in the Node class with the following signatures:

A base URI is scoped to an Element (and Document). The
value of a base URI predominantly used to qualify the
value of a (link) Attribute. Add these methods to
ParentNode, to cover Element and Document, and to
Attribute. It doesn't make sense for the various
LeafNode types to contain these methods.

> 1. Should I make any checks that this is a legal URI? That is,
> should I check that these values are syntactically correct URIs
> according to RFC 2396? I do make these checks for namespace URIs, (which
> is aggressive in itself) but here nothing you could put in this property
> would make the document malformed.

Enforce URI syntax, as with namespace URIs. Least surprise
and all.

> 2. Should I allow relative URIs or only absolute URIs?

Accept only absolute URIs for base URIs. I think that's
what the XML Base recommendation says, I could be mistaken.

> 3. Should I allow URIs at all, or should this just be a URL?

URIs will be more general, since not all resources need
to be "located". Imagine an application that supports
relative URIs for namespaces.

> 6. How do I handle xml:base attributes? Should they be included in an
> element's list of attributes? Should the setBaseURI method check for
> conflicts with an xml:base attribute? What should it do if it notices
> one? Should extra xml:base attributes be automatically generated as
> necessary when the document is serialized?

xml:base attributes should be treated analogously to xmlns:xxx
attributes. That is, the API should handle them on input and
produce them as needed on output.

-- michael mceniry