SAX2 and DOM2

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SAX2 and DOM2

• Kanda Runapongsa
• (krunapon_at_kku.ac.th)
• Dept. of Computer Engineering
• Khon Kaen University

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SAX

• An event-based architecture for processing XML
  documents
• To use SAX, you create a class that implements
  one of the SAX listener interfaces and register
  an instance of that class with a SAX parser at
  runtime

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How Does SAX Work?

• A SAX parser reads an XML document from a data
  stream, sequentially from beginning to end
• As it reads the stream, the SAX parser sends
  event to the listener object that you registered
• The parser invokes callback methods on the
  listener object as it encounters different parts
  of the XML document

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How Does SAX Work? (Cont.)

• At the start of the XML document, the parser
  invokes the listeners startDocument() method
• When it reads the start tag of an element, it
  invokes the listeners startElement() method
• When it reads the end tag of an element, it
  invokes the listeners endElement() method

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DOM

• A set of interfaces and classes used to model XML
  documents as a tree of objects called nodes
• You use the DOM programming API to examine
  existing XML documents, or to create new nodes or
  to remove existing nodes

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How Does DOM Work?

• When an implementation of DOM parses an XML
  document, it reads the XML text from some source
• Then it builds an object graph, called a tree,
  that mirrors the structure of the XML document