This helper class implements the four commonly-used
SAX handler interfaces from the org.xml.sax
package and defines stub implementations for all of their methods. It
is usually easier to subclass DefaultHandler and
override the desired methods than it is to implement all of the
interfaces (and all of their methods) from scratch.
DefaultHandler implements
ContentHandler, ErrorHandler,
EntityResolver and DTDHandler,
so you can pass an instance of this class, (or of a subclass you
define) to the setContentHandler( ),
setErrorHandler( ), setEntityResolver(
), and setDTDHandler( ) methods of an
XMLReader. You can also pass an instance of a
DefaultHandler subclass directly to one of the
parse( ) methods of a
javax.xml.parsers.SAXParser. The
SAXParser will take care of calling the four
relevant methods of its internal XMLReader.
All but two of the methods of DefaultHandler have
empty bodies and do nothing. The exceptions are
resolveEntity( ) which simply returns
null to tell the parser to resolve the entity
itself, and fatalError( ) which throws the
SAXParseException object that is passed to it.
Figure 22-15. org.xml.sax.helpers.DefaultHandler
public class
DefaultHandler implements org.xml.sax.ContentHandler,
org.xml.sax.DTDHandler, org.xml.sax.EntityResolver,
org.xml.sax.ErrorHandler {
// Public Constructors
public
DefaultHandler ( );
// Methods Implementing ContentHandler
public void
characters (char[ ]
ch , int
start , int
length )
throws org.xml.sax.SAXException; empty
public void
endDocument ( ) throws org.xml.sax.SAXException; empty
public void
endElement (String
uri , String
localName , String
qName )
throws org.xml.sax.SAXException; empty
public void
endPrefixMapping (String
prefix ) throws org.xml.sax.SAXException; empty
public void
ignorableWhitespace (char[ ]
ch , int
start , int
length )
throws org.xml.sax.SAXException; empty
public void
processingInstruction (String
target , String
data )
throws org.xml.sax.SAXException; empty
public void
setDocumentLocator (org.xml.sax.Locator
locator ); empty
public void
skippedEntity (String
name ) throws org.xml.sax.SAXException; empty
public void
startDocument ( ) throws org.xml.sax.SAXException; empty
public void
startElement (String
uri , String
localName , String
qName ,
org.xml.sax.Attributes
attributes )
throws org.xml.sax.SAXException; empty
public void
startPrefixMapping (String
prefix , String
uri )
throws org.xml.sax.SAXException; empty
// Methods Implementing DTDHandler
public void
notationDecl (String
name , String
publicId , String
systemId )
throws org.xml.sax.SAXException; empty
public void
unparsedEntityDecl (String
name , String
publicId , String
systemId ,
String
notationName )
throws org.xml.sax.SAXException; empty
// Methods Implementing EntityResolver
public org.xml.sax.InputSource
resolveEntity (String
publicId , String
systemId )
throws java.io.IOException, org.xml.sax.SAXException; constant
// Methods Implementing ErrorHandler
public void
error (org.xml.sax.SAXParseException
e )
throws org.xml.sax.SAXException; empty
public void
fatalError (org.xml.sax.SAXParseException
e )
throws org.xml.sax.SAXException;
public void
warning (org.xml.sax.SAXParseException
e )
throws org.xml.sax.SAXException; empty
}