This section describes the SAX 1.0 and 2.0 standards. SAX defines 4 interfaces under the org.xml.sax package name: DocumentHandler, ErrorHandler, DTDHandler and EntityResolver.
Unlike DOM, there is no formal specification for SAX.
The original SAX Java implementation by the SAX Project is considered as the standard.
There are 2 major versions released by the SAX Project:
SAX 1.0 - Released on May 12, 1998.
SAX 2.0 - Released on May 5, 2000. In SAX 2.0, the structure and concepts remained largely the same,
although several key interfaces changed incompatibly.
The SAX API is defined in 4 interfaces under the org.xml.sax package:
org.xml.sax.DocumentHandler -
This is the main interface of SAX.
It defines event handler methods (callback methods) that an application should implement to handle events
fired by the parser while it traverses the input XML files.
org.xml.sax.ErrorHandler -
It defines error handler methods (callback methods) that an applications should implement to add special handling logics
when the parse encountered parsing errors.
org.xml.sax.DTDHandler -
If an application needs to work with notations and unparsed (binary) entities,
it must implement this interface to receive notification of the NOTATION and ENTITY declarations.
org.xml.sax.EntityResolver -
If an application needs to do redirection of URIs in documents (or other types of custom handling),
it must provide an implementation of this interface.
The main interface of SAX, org.xml.sax.ContentHandler defines the following event handler methods
to be implemented by applications:
startDocument(): Called when parsing reaches the beginning of the XML document.
endDocument(): Called when parsing reaches the end of the XML document.
startElement(): Called when parsing reaches the beginning of an XML element.
endElement(): Called when parsing reaches the end of an XML element.
characters(): Called when parsing reaches the end of an character section.
ignorableWhitespace(): Called when parsing reaches any ignorable white spaces between elements.
Of course, some of the event handlers will receive information parsed from the XML file as parameters. For example:
startElement() passes all the attributes as an org.xml.sax.Attributes object.
characters() passes all the characters of the parsed text as char[] object.
