This package, SAX2-ext, is an extension package for SAX2. It is designed both to allow SAX drivers to pass certain types of none-core information to applications and to serve as a simple model for other SAX2 extension packages.

NOTE: this package alone does add any functionality; it simply provides optional interfaces for SAX2 drivers to use. You must find a SAX2 driver that supports these interfaces if you actually want to have access to lexical and declaration information.

The SAX2-ext package currently contains two extension handlers for SAX2:

1. LexicalHandler, which reports comments, the DOCTYPE declaration, CDATA sections, and (some) entity boundaries; and
2. DeclHandler, which reports element, attribute, and entity declarations.

This package is independent of the SAX2 core, and that independence has several consequences:

• SAX2 drivers are not required to support these handlers, and you cannot assume that the classes will be present in every SAX2 installation.
• This package may be updated independently of SAX2 (i.e. new handlers may be added without updating SAX2 itself).
• The handlers are not supported explicitly by the SAX2 XMLFilter interface (i.e. events are not passed on by default); you can subclass XMLFilter if you need such behaviour.
• The handlers need to be registered differently than regular SAX2 handlers.

To set a LexicalHandler, for example, you need to do something like this:

LexicalHandler lh = new MyLexicalHandler();
try {
  xmlReader.setProperty("http://xml.org/sax/properties/lexical-handler",
                        lh);
} catch (SAXException e) {
  System.out.println("LexicalHandler not supported by this SAX2 driver.");
}