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Xerces
The Apache XML Project
Yvonne Yao
Introduction
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Set of libraries that provides functionalities
to parse XML documents
Promotes the use of XML
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Why?
Two types of parsers
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DOM (Document Object Model) parsers
SAX (Simple API for XML) parsers
DOM & SAX
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DOM
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Implements the DOM API
Creates a DOM tree in memory
Good for small XML files, or traverse the document
back and forth
SAX
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Implements SAX API
Event driven interface
Good for huge XML files
Xerces
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Implements both DOM and SAX parsers
3 subprojects
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Xerces C++
Xerces Java
Xerces Perl
Xerces C++
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Current version 2.7.0
Provides functionalities to read, write,
parse, and validate XML documents
Conforms with
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XML 1.0 and XML 1.1
SAX 1.0 and SAX 2.0
DOM Level 1 and 2
Xerces Perl
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Current version 2.7.0
Implemented using the Xerces C++ API
Provides access to most of the C++ API, except
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Functions in the C++ API which have better Perl
counterparts (such as file I/O), or
Functions that manipulate internal C++ information
that has no role in the Perl module
Conforms to the same set of Standards as
Xerces C++
Xerces Java
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Xerces Java
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Current version 1.4.4
Conforms with
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XML 1.0
SAX 1.0 and 2.0
DOM Level 2
Xerces2 Java
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Current version 2.9.0
Includes Xerces Native Interface, a new framework
for building parser components and configurations
Example 1 - DOM
<?xml version="1.0" encoding="UTF-8"?>
<Personnel>
<Employee type="permanent">
<Name>Seagull</Name>
<Id>3674</Id>
<Age>34</Age>
</Employee>
<Employee type="contract">
<Name>Robin</Name>
<Id>3675</Id>
<Age>25</Age>
</Employee>
<Employee type="permanent">
<Name>Crow</Name>
<Id>3676</Id>
<Age>28</Age>
</Employee>
</Personnel>
Example 1 - DOM
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Create a DOM object
DocumentBuilderFactory dbf =
DocumentBuilderFactory.newInstance();
DocumentBuilder db =
dbf.newDocumentBuilder();
dom = db.parse("employees.xml");
Get a list of employee elements from DOM
Element docEle = dom.getDocumentElement();
NodeList nl =
docEle.getElementsByTagName("Employee");
Get node value from element
element.getFirstChild().getNodeValue();
Example 2 - SAX
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SAX parsing is event based modeling, it calls a
tag handler whenever it encounters a tag
public void startElement(String uri,
String localName, String qName,
Attributes attributes)
public void endElement(String uri, String
localName, String qName)
Example 2 - SAX
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Create a SAX parser
SAXParserFactory spf =
SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
sp.parse("employees.xml", this);
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Create Employee object when <Employee> is found
if(qName.equalsIgnoreCase("Employee"))
tempEmp = new Employee();
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Set Employee properties when an end tag is found
if (qName.equalsIgnoreCase("Name"))
tempEmp.setName(tempVal);
Thank You