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<!--
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* saxparser.html
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*
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* Authors: Jivka Bojilova
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* Copyright: 2000 Regents of the University of California and the
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* National Center for Ecological Analysis and Synthesis
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* For Details: http://www.nceas.ucsb.edu/
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* Created: 2000 April 5
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* Version: 0.01
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* File Info: '$Id: saxparser.html 878 2001-12-18 18:11:42Z berkley $'
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*
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* October Meeting SDSC, 2000
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-->
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<HTML>
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<HEAD>
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<TITLE>Metacat</TITLE>
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<link rel="stylesheet" type="text/css" href="@docrooturl@default.css">
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</HEAD>
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<BODY>
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<table width="100%">
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<tr>
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<td class="tablehead" colspan="2"><p class="label">XML Parsing with SAX</p></td>
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<td class="tablehead" colspan="2" align="right">
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<a href="./metacatread.html">Back</a> | <a href="./metacattour.html">Home</a> |
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<a href="./xmlindex.html">Next</a>
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</td>
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</tr>
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</table>
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<P>SAX, the <i>Simple API for XML</i>, is
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a standard interface for event-based XML parsing. The SAX API provides implemented
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interfaces for many different XML parsers. Metacat requires a SAX2
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API/Java1.2 with any SAX2-compatible XML parser.
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<P>To avoid tying Metacat to any specific SAX parser, XMLReaderFactory is used
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as the SAX interface to Metacat for easy plugability of parsers. The SAX parser
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used must be set in the <a href="./properties.html">Metacat Properties</a> file.</p>
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<p>The following is an example of instatiating a parser for Metacat.</p>
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<PRE>
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XMLReader parser = null;
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// Set up the SAX document handlers for parsing
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try {
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ContentHandler chandler = new DBSAXHandler(conn, action, docid, user);
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EntityResolver dbresolver = new DBEntityResolver(conn, (DBSAXHandler)chandler);
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DTDHandler dtdhandler = new DBDTDHandler(conn);
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// Get an instance of the parser
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MetacatUtil util = new MetacatUtil();
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// Get the class name of SAX driver from some XML parser like:
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// org.apache.xerces.parsers.SAXParser
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<span class="emphasis">String parserName = util.getOption("saxparser");</span>
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// Given a class name, this method attempts to load and instantiate the class as an XML reader
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<span class="emphasis">parser = XMLReaderFactory.createXMLReader(parserName);</span>
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// Turn off validation
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parser.setFeature("http://xml.org/sax/features/validation", false);
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parser.setProperty("http://xml.org/sax/properties/declaration-handler", chandler);
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parser.setProperty("http://xml.org/sax/properties/lexical-handler", chandler);
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// Set Handlers in the parser to receive XML parsing events
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parser.setContentHandler((ContentHandler)chandler);
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parser.setEntityResolver((EntityResolver)dbresolver);
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parser.setDTDHandler((DTDHandler)dtdhandler);
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parser.setErrorHandler((ErrorHandler)chandler);
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} catch (SAXException saxe) {
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throw saxe;
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}
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</PRE>
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<br>
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<a href="./metacatread.html">Back</a> | <a href="./metacattour.html">Home</a> |
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<a href="./xmlindex.html">Next</a>
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</BODY>
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</HTML>
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