Java and XML, Second Edition

JAXP 1.0

It all begins (and began) with JAXP 1.0. This first version of Sun’s API provided, basically, a thin layer over existing APIs that allowed for vendor-neutral parsing of code. For SAX, this isn’t a huge deal; now that you are a SAX expert, you are smart enough to use the XMLReaderFactory class instead of directly instantiating a vendor’s parser class. Of course, as you’re also a DOM expert, you know that it’s a pain to deal with DOM in a vendor-neutral way, so JAXP helps out quite a bit in this regard. Additionally, JAXP provided some methods for working with validation and namespaces, another vendor-specific task that can now be handled (in most cases) in a much better way.

Starting with SAX

Before getting into how JAXP works with SAX, I will fill you in on some SAX 1.0 details. Remember the org.xml.sax.helpers.DefaultHandler class I showed you in Chapter 4 that implemented all the core SAX 2.0 handlers? There was a similar class in SAX 1.0 called org.xml.sax.HandlerBase ; this class implemented the SAX 1.0 handlers (which were slightly different in that version). As long as you understand this, you’ll be all set to deal with JAXP 1.0.

To use JAXP with a SAX-compliant parser, your only task is to extend the HandlerBase class and implement the callbacks desired for your application. That’s it, no different than doing the same for DefaultHandler in SAX 2.0. An instance of your extension class then becomes the core argument for most of the JAXP methods that deal with ...