XML Parser for Java - XSL Example 1: XSL (iden.xsl)

Using XML Parser for Java: DOMParser() Class









XML Parser for Java - DTD Example 1: (NSExample)












]>


xmlns:nsprefix="http://www.oracle.com">



This element inherits the default Namespace of doc.







Using XML Parser for Java: DOMParser() Class

To write DOM based parser applications you can use the following classes:

s



DOMNamespace() class



s



DOMParser() class



s



XMLParser() class



Since DOMParser extends XMLParser, all methods of XMLParser are also available

to DOMParser. Figure 4–4 shows the main steps you need when coding with the

DOMParser() class:

s



Without DTD Input

1.



A new DOMParser() class is called. Available properties to use with this

class are:

*



setValidateMode



*



setPreserveWhiteSpace



*



setDocType



*



setBaseURL



*



showWarnings



XML Parser for Java 4-15



Using XML Parser for Java: DOMParser() Class



2.



The results of 1) are passed to XMLParser.parse() along with the XML

input. The XML input can be a file, a string buffer, or URL.



3.



Use the XMLParser.getDocument() method.



4.



Optionally, you can apply other DOM methods such as:

*



print()



*



DOMNamespace() methods



5.

6.



s



The Parser outputs the DOM tree XML (parsed) document.

Optionally, use DOMParser.reset() to clean up any internal data

structures, once the Parser has finished building the DOM tree.



With a DTD Input

1.



A new DOMParser() class is called. The available properties to apply to

this class are:

*



setValidateMode



*



setPreserveWhiteSpace



*



setDocType



*



setBaseURL



*



showWarnings



2.



The results of 1) are passed to XMLParser.parseDTD() method along

with the DTD input.



3.



XMLParser.getDocumentType() method then sends the resulting DTD

object back to the new DOMParser() and the process continues until the

DTD has been applied.



The example, "XML Parser for Java Example 1: Using the Parser and DOM API",

shows hoe to use DOMParser() class.



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Using XML Parser for Java: DOMParser() Class



Figure 4–4 XML Parser for Java: DOMParser()



XDK for Java: XML Parser for Java — DOM Parser()



new

DOMParser()



Available properties:

· setValidationMode

[default = not]

· setPreserveWhiteSpace

[default = not]

· setDocType

[if input type is a DTD]

· setBaseURL

[refers other locations to

base location if reading

from outside source ]

· showWarnings



file, string

buffer, or URL

xml input



DTD input



XMLParser.

parse()



XMLParser.

parseDTD()



XMLParser.

getDocument



XMLParser.

getDocumentType()



Apply other

DOM methods



DOMParser.

reset()



DTD

object



Typically Node

class methods

To print, use the

print method.

This is a

nonstandard

DOM method



DOM

document



XML Parser for Java Example 1: Using the Parser and DOM API

The examples represent the way we write code so it is required to present the

examples with Java coding standards (like all imports expanded), with

documentation headers before the methods, and so on.

//

//

//

//



This file demonstates a simple use of the parser and DOM API.

The XML file given to the application is parsed.

The elements and attributes in the document are printed.

This demonstrates setting the parser options.



XML Parser for Java 4-17



Using XML Parser for Java: DOMParser() Class



//

import

import

import

import



java.io.*;

java.net.*;

org.w3c.dom.*;

org.w3c.dom.Node;



import oracle.xml.parser.v2.*;

public class DOMSample

{

static public void main(String[] argv)

{

try

{

if (argv.length != 1)

{

// Must pass in the name of the XML file.

System.err.println("Usage: java DOMSample filename");

System.exit(1);

}

// Get an instance of the parser

DOMParser parser = new DOMParser();

// Generate a URL from the filename.

URL url = createURL(argv[0]);

// Set various parser options: validation on,

// warnings shown, error stream set to stderr.

parser.setErrorStream(System.err);

parser.setValidationMode(DTD_validation);

parser.showWarnings(true);

// Parse the document.

parser.parse(url);

// Obtain the document.

XMLDocument doc = parser.getDocument();

// Print document elements

System.out.print("The elements are: ");

printElements(doc);

// Print document element attributes



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Using XML Parser for Java: DOMParser() Class



System.out.println("The attributes of each element are: ");

printElementAttributes(doc);

parser.reset();

}

catch (Exception e)

{

System.out.println(e.toString());

}

}

static void printElements(Document doc)

{

NodeList nl = doc.getElementsByTagName("*");

Node n;

for (int i=0; i
{

n = nl.item(i);

System.out.print(n.getNodeName() + " ");

}

System.out.println();

}

static void printElementAttributes(Document doc)

{

NodeList nl = doc.getElementsByTagName("*");

Element e;

Node n;

NamedNodeMap nnm;

String attrname;

String attrval;

int i, len;

len = nl.getLength();

for (int j=0; j < len; j++)

{

e = (Element)nl.item(j);

System.out.println(e.getTagName() + ":");

nnm = e.getAttributes();

if (nnm != null)

{

for (i=0; i
{



XML Parser for Java 4-19



Using XML Parser for Java: DOMParser() Class



n = nnm.item(i);

attrname = n.getNodeName();

attrval = n.getNodeValue();

System.out.print(" " + attrname + " = " + attrval);

}

}

System.out.println();

}

}

static URL createURL(String fileName)

{

URL url = null;

try

{

url = new URL(fileName);

}

catch (MalformedURLException ex)

{

File f = new File(fileName);

try

{

String path = f.getAbsolutePath();

String fs = System.getProperty("file.separator");

if (fs.length() == 1)

{

char sep = fs.charAt(0);

if (sep != '/')

path = path.replace(sep, '/');

if (path.charAt(0) != '/')

path = '/' + path;

}

path = "file://" + path;

url = new URL(path);

}

catch (MalformedURLException e)

{

System.out.println("Cannot create url for: " + fileName);

System.exit(0);

}

}

return url;

}

}



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Using XML Parser for Java: DOMParser() Class



Comments on DOMParser() Example 1

See also Figure 4–4. The following provides comments for Example 1:

1.



Declare a new DOMParser(). In Example 1, see the line:

DOMParser parser = new DOMParser();



This class has several properties you can use. Here the example uses:

parser.setErrorStream(System.err);

parser.setValidationMode(DTD_validation);

parser.showWarnings(true);

2.



The XML input is a URL as declared by:

URL url = createURL(argv[0])



3.



The XML document is input as a URL. This is parsed using parser.parse():

parser.parse(url);



4.



Gets the document:

XMLDocument doc = parser.getDocument();



5.



Applies other DOM methods. In this case:

s



Node class methods:

*

*



getAttributes()



*



getNodeName()



*

s



getElementsByTagName()



getNodeValue()



Method, createURL() to convert the string name into a URL.



6.



parser.reset() is called to clean up any data structure created during the parse

process, after the DOM tree has been created. Note that this is a new method

with this release.



7.



Generates the DOM tree (parsed XML) document for further processing by

your application.

Note: No DTD input is shown in Example 1.



XML Parser for Java 4-21



Using XML Parser for Java: DOMNamespace() Class



Using XML Parser for Java: DOMNamespace() Class

Figure 4–3 illustrates the main processes involved when parsing an XML document

using the DOM interface. The DOMNamespace() method is applied in the parser

process at the “bubble” that states “Apply other DOM methods”. The following

example illustrates how to use DOMNamespace():

s



"XML Parser for Java Example 2: Parsing a URL — DOMNamespace.java"



XML Parser for Java Example 2: Parsing a URL — DOMNamespace.java

//

//

//

//

//



This file demonstates a simple use of the parser and Namespace

extensions to the DOM APIs.

The XML file given to the application is parsed and the

elements and attributes in the document are printed.



import java.io.*;

import java.net.*;

import oracle.xml.parser.v2.DOMParser;

import org.w3c.dom.*;

import org.w3c.dom.Node;

// Extensions to DOM Interfaces for Namespace support.

import oracle.xml.parser.v2.XMLElement;

import oracle.xml.parser.v2.XMLAttr;



public class DOMNamespace

{

static public void main(String[] argv)

{

try

{

if (argv.length != 1)

{

// Must pass in the name of the XML file.

System.err.println("Usage: DOMNamespace filename");

System.exit(1);

}

// Get an instance of the parser

Class cls = Class.forName("oracle.xml.parser.v2.DOMParser");



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Using XML Parser for Java: DOMNamespace() Class



DOMParser parser = (DOMParser)cls.newInstance();

// Generate a URL from the filename.

URL url = createURL(argv[0]);

// Parse the document.

parser.parse(url);

// Obtain the document.

Document doc = parser.getDocument();

// Print document elements

printElements(doc);

// Print document element attributes

System.out.println("The attributes of each element are: ");

printElementAttributes(doc);

}

catch (Exception e)

{

System.out.println(e.toString());

}

}

static void printElements(Document doc)

{

NodeList nl = doc.getElementsByTagName("*");

XMLElement nsElement;

String

String

String

String



qName;

localName;

nsName;

expName;



System.out.println("The elements are: ");

for (int i=0; i < nl.getLength(); i++)

{

nsElement = (XMLElement)nl.item(i);

// Use the methods getQualifiedName(), getLocalName(), getNamespace()

// and getExpandedName() in NSName interface to get Namespace

// information.

qName = nsElement.getQualifiedName();

System.out.println(" ELEMENT Qualified Name:" + qName);



XML Parser for Java 4-23