XOM API for Processing XML with Java

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

The more I think about using NodeFactory as a filter, the more 
excited I get. This is really neat stuff. I'm still playing with the 
exact interface, but I think I've pretty much solved the Shemp 
problem tonight. The key is the following endElement() method in 
NodeFactory which XOMHandler calls from endElement():

protected void endElement(Element element);

A subclass of NodeFactory can use this as a simple callback to 
process just that one element. It can invoke any method it needs to 
invoke on the element to decide whether or not to process it. Then, 
if the element is no longer needed after processing, the subclass can 
detach it so it can be garbage collected. This very neatly merges 
streaming and tree-based processing.

This has been done before (Simon St. Laurent's MOE, Laurent Bihanic's 
ElementScanner in JDOM) but I don't think I've seen any API make it 
as simple as XOM makes it. I'm going through the samples now and 
finding tons of opportunities to use this. This is really powerful 
stuff, and the real beauty is that if you don't need this you can 
completely ignore it. Enabling this pattern in XOM only required 
adding two protected methods (there's an endDocument method as well) 
and no additional public methods or classes.
--

  Elliotte Rusty Harold
  elharo AT metalab.unc.edu
  Processing XML with Java (Addison-Wesley, 2002)
  http://www.cafeconleche.org/books/xmljava
  http://www.amazon.com/exec/obidos/ISBN%3D0201771861/cafeaulaitA