XOM API for Processing XML with Java

[John Cowan <cowan AT mercury.ccil.org>]

Elliotte Rusty Harold scripsit:

> By default returning null from startElement() will simply remove the 
> start-tags and end-tags, but retain the element's content. A custom 
> builder could easily change this behavior to remove everything inside 
> the element. In DOM terms this is a skip rather than a reject. I am 
> wondering if I've got this backwards. Perhaps by default returning 
> null from startElement() should remove everything inside the element, 
> and there should be some way to override this behavior? Thoughts?

This is a classic datahead/dochead split, and the fact that you're
ambivalent shows that you have some of each in your makeup.  :-)
Dataheads think of an element as a container for its content, and
if the container is removed, the content goes to Tumbolia with it.
Docheads think of elements as basically annotations of ranges, and if
the annotation is removed, the underlying content remains.

I don't think you can make everyone happy here.  Just make sure that
*some* path through the code makes it possible to do either operation.

> Another open question are other uses of NodeFactory as a filter. In 
> XOM today it is possible to change the name or namespace or 
> attributes of an element as its built. Should it be possible to go 
> further and replace an element with a processing instruction or vice 
> versa? i.e. to substitute a different kind of node in the tree? All 
> enabling this would really require is having the various makeXXX 
> methods return Node instead of the more specific type. However, this 
> might expand the type-checking in other parts of the code which is 
> expensive, so I'd prefer not to do it unless there's a good use-case.

How clever would this be?  If I returned an attribute, or text, where
you expected an element, would it become an attribute of/part of the
content of the parent element?  If so, this would be a Good Thing for
architectural forms support.

-- 
John Cowan  jcowan AT reutershealth.com  www.reutershealth.com  
www.ccil.org/~cowan
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