sax.DocumentTracer and sax.Writer

XSD Tutorials - Herong's Tutorial Examples

∟Xerces2 Java Parser - Java API of XML Parsers

∟sax.DocumentTracer and sax.Writer

This section provides tutorial examples on how to use sample programs sax.DocumentTracer and sax.Writer to validate XML documents with XSD schema. Their error reporting format is better than dom.GetElementsByTagName and dom.Writer.

If you want a better validation error report that shows the XML structure with errors located inside the structure, you can also try the 2 SAX technology sample programs. They also support XSD schema validation:

sax.DocumentTracer - Printing out parsing events in tree format using SAX technology.
sax.Writer - Writing back elements, attributes, and contents using SAX technology.

Here is my test result:

herong> java_xerces sax.DocumentTracer -v -s hello_xsd_invalid.xml

setDocumentLocator(locator=org.apache.xerces.parsers
^^^.AbstractSAXParser$LocatorProxy@1a52fbd)
startDocument()
 startPrefixMapping(prefix="xsi",uri="http://www.w3.org/2001
^^^/XMLSchema-instance")
 startElement(uri="",localName="p",qname="p",attributes={{uri=
^^^"http://www.w3.org/2001/XMLSchema-instance",localName=
^^^"noNamespaceSchemaLocation",qname="xsi:noNamespaceSchemaLocation",
^^^type="CDATA",value="hello.xsd"}})
  characters(text="\nHello ")
  startElement(uri="",localName="i",qname="i",attributes={})
   characters(text="world")
  endElement(uri="",localName="i",qname="i")
  characters(text="!")

[Error] hello_xsd_invalid.xml:4:24: cvc-type.3.1.2: Element 'p' is a
^^^ simple type, so it must have no element information item
^^^ [children].
 endElement(uri="",localName="p",qname="p")
 endPrefixMapping(prefix="xsi")
endDocument()


herong> java_xerces sax.Writer -v -s hello_xsd_invalid.xml

<?xml version="1.0" encoding="UTF-8"?>
<p xsi:noNamespaceSchemaLocation="hello.xsd">
Hello <i>world</i>![Error] hello_xsd_invalid.xml:4:24: cvc-type.3.1.2:
^^^ Element 'p' is a simple type, so it must have no element
^^^ information item [children].
</p>

Cool. Both sax.DocumentTracer and sax.Writer can be used as validation tools on XML documents associated with XSD schema. Their error reporting format is better than dom.GetElementsByTagName and dom.Writer, since error messages are embedded inside the XML structure printout next to the place where errors occurred.

Between sax.Writer and sax.DocumentTracer, sax.Writer's output format is better, since it prints out the XML document in the original format with error messages embedded.