/* StdXMLBuilder.java NanoXML/Java
*
* $Revision: 1.3 $
* $Date: 2002/01/04 21:03:28 $
* $Name: RELEASE_2_2_1 $
*
* This file is part of NanoXML 2 for Java.
* Copyright (C) 2000-2002 Marc De Scheemaecker, All Rights Reserved.
*
* This software is provided 'as-is', without any express or implied warranty.
* In no event will the authors be held liable for any damages arising from the
* use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software in
* a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
*
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
*
* 3. This notice may not be removed or altered from any source distribution.
*/
package edu.isi.karma.modeling.research.graphmatching.net.n3.nanoxml;
import java.io.IOException;
import java.io.Reader;
import java.util.Stack;
/**
* @author kriesen
*/
public class StdXMLBuilder
implements IXMLBuilder
{
/**
* This stack contains the current element and its parents.
*/
private Stack stack;
/**
* The root element of the parsed XML tree.
*/
private IXMLElement root;
/**
* Prototype element for creating the tree.
*/
private IXMLElement prototype;
/**
* Creates the builder.
*/
public StdXMLBuilder()
{
this(new XMLElement());
}
/**
* Creates the builder.
*
* @param prototype the prototype to use when building the tree.
*/
public StdXMLBuilder(IXMLElement prototype)
{
this.stack = null;
this.root = null;
this.prototype = prototype;
}
/**
* Cleans up the object when it's destroyed.
*/
protected void finalize()
throws Throwable
{
this.prototype = null;
this.root = null;
this.stack.clear();
this.stack = null;
super.finalize();
}
/**
* This method is called before the parser starts processing its input.
*
* @param systemID the system ID of the XML data source.
* @param lineNr the line on which the parsing starts.
*/
public void startBuilding(String systemID,
int lineNr)
{
this.stack = new Stack();
this.root = null;
}
/**
* This method is called when a processing instruction is encountered.
* PIs with target "xml" are handled by the parser.
*
* @param target the PI target.
* @param reader to read the data from the PI.
*/
public void newProcessingInstruction(String target,
Reader reader)
{
// nothing to do
}
/**
* This method is called when a new XML element is encountered.
*
* @see #endElement
*
* @param name the name of the element.
* @param nsPrefix the prefix used to identify the namespace. If no
* namespace has been specified, this parameter is null.
* @param nsURI the URI associated with the namespace. If no
* namespace has been specified, or no URI is
* associated with nsPrefix, this parameter is null.
* @param systemID the system ID of the XML data source.
* @param lineNr the line in the source where the element starts.
*/
public void startElement(String name,
String nsPrefix,
String nsURI,
String systemID,
int lineNr)
{
String fullName = name;
if (nsPrefix != null) {
fullName = nsPrefix + ':' + name;
}
IXMLElement elt = this.prototype.createElement(fullName, nsURI,
systemID, lineNr);
if (this.stack.empty()) {
this.root = elt;
} else {
IXMLElement top = (IXMLElement) this.stack.peek();
top.addChild(elt);
}
this.stack.push(elt);
}
/**
* This method is called when the attributes of an XML element have been
* processed.
*
* @see #startElement
* @see #addAttribute
*
* @param name the name of the element.
* @param nsPrefix the prefix used to identify the namespace. If no
* namespace has been specified, this parameter is null.
* @param nsURI the URI associated with the namespace. If no
* namespace has been specified, or no URI is
* associated with nsPrefix, this parameter is null.
*/
public void elementAttributesProcessed(String name,
String nsPrefix,
String nsURI)
{
// nothing to do
}
/**
* This method is called when the end of an XML elemnt is encountered.
*
* @see #startElement
*
* @param name the name of the element.
* @param nsPrefix the prefix used to identify the namespace. If no
* namespace has been specified, this parameter is null.
* @param nsURI the URI associated with the namespace. If no
* namespace has been specified, or no URI is
* associated with nsPrefix, this parameter is null.
*/
public void endElement(String name,
String nsPrefix,
String nsURI)
{
IXMLElement elt = (IXMLElement) this.stack.pop();
if (elt.getChildrenCount() == 1) {
IXMLElement child = elt.getChildAtIndex(0);
if (child.getName() == null) {
elt.setContent(child.getContent());
elt.removeChildAtIndex(0);
}
}
}
/**
* This method is called when a new attribute of an XML element is
* encountered.
*
* @param key the key (name) of the attribute.
* @param nsPrefix the prefix used to identify the namespace. If no
* namespace has been specified, this parameter is null.
* @param nsURI the URI associated with the namespace. If no
* namespace has been specified, or no URI is
* associated with nsPrefix, this parameter is null.
* @param value the value of the attribute.
* @param type the type of the attribute. If no type is known,
* "CDATA" is returned.
*
* @throws java.lang.Exception
* If an exception occurred while processing the event.
*/
public void addAttribute(String key,
String nsPrefix,
String nsURI,
String value,
String type)
throws Exception
{
String fullName = key;
if (nsPrefix != null) {
fullName = nsPrefix + ':' + key;
}
IXMLElement top = (IXMLElement) this.stack.peek();
if (top.hasAttribute(fullName)) {
throw new XMLParseException(top.getSystemID(),
top.getLineNr(),
"Duplicate attribute: " + key);
}
if (nsPrefix != null) {
top.setAttribute(fullName, nsURI, value);
} else {
top.setAttribute(fullName, value);
}
}
/**
* This method is called when a PCDATA element is encountered. A Java
* reader is supplied from which you can read the data. The reader will
* only read the data of the element. You don't need to check for
* boundaries. If you don't read the full element, the rest of the data
* is skipped. You also don't have to care about entities; they are
* resolved by the parser.
*
* @param reader the Java reader from which you can retrieve the data.
* @param systemID the system ID of the XML data source.
* @param lineNr the line in the source where the element starts.
*/
public void addPCData(Reader reader,
String systemID,
int lineNr)
{
int bufSize = 2048;
int sizeRead = 0;
StringBuffer str = new StringBuffer(bufSize);
char[] buf = new char[bufSize];
for (;;) {
if (sizeRead >= bufSize) {
bufSize *= 2;
str.ensureCapacity(bufSize);
}
int size;
try {
size = reader.read(buf);
} catch (IOException e) {
break;
}
if (size < 0) {
break;
}
str.append(buf, 0, size);
sizeRead += size;
}
IXMLElement elt = this.prototype.createElement(null, systemID, lineNr);
elt.setContent(str.toString());
if (! this.stack.empty()) {
IXMLElement top = (IXMLElement) this.stack.peek();
top.addChild(elt);
}
}
/**
* Returns the result of the building process. This method is called just
* before the <I>parse</I> method of IXMLParser returns.
*
* @see net.n3.nanoxml.IXMLParser#parse
*
* @return the result of the building process.
*/
public Object getResult()
{
return this.root;
}
}