Java example source code file (DOM2SAX.java)
The DOM2SAX.java Java example source code/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* $Id: DOM2SAX.java,v 1.2.4.1 2005/09/06 11:52:46 pvedula Exp $
*/
package com.sun.org.apache.xalan.internal.xsltc.trax;
import java.io.IOException;
import java.util.Hashtable;
import java.util.Stack;
import java.util.Vector;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.helpers.AttributesImpl;
import com.sun.org.apache.xalan.internal.xsltc.dom.SAXImpl;
import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
/**
* @author G. Todd Miller
*/
public class DOM2SAX implements XMLReader, Locator {
private final static String EMPTYSTRING = "";
private static final String XMLNS_PREFIX = "xmlns";
private Node _dom = null;
private ContentHandler _sax = null;
private LexicalHandler _lex = null;
private SAXImpl _saxImpl = null;
private Hashtable _nsPrefixes = new Hashtable();
public DOM2SAX(Node root) {
_dom = root;
}
public ContentHandler getContentHandler() {
return _sax;
}
public void setContentHandler(ContentHandler handler) throws
NullPointerException
{
_sax = handler;
if (handler instanceof LexicalHandler) {
_lex = (LexicalHandler) handler;
}
if (handler instanceof SAXImpl) {
_saxImpl = (SAXImpl)handler;
}
}
/**
* Begin the scope of namespace prefix. Forward the event to the
* SAX handler only if the prefix is unknown or it is mapped to a
* different URI.
*/
private boolean startPrefixMapping(String prefix, String uri)
throws SAXException
{
boolean pushed = true;
Stack uriStack = (Stack) _nsPrefixes.get(prefix);
if (uriStack != null) {
if (uriStack.isEmpty()) {
_sax.startPrefixMapping(prefix, uri);
uriStack.push(uri);
}
else {
final String lastUri = (String) uriStack.peek();
if (!lastUri.equals(uri)) {
_sax.startPrefixMapping(prefix, uri);
uriStack.push(uri);
}
else {
pushed = false;
}
}
}
else {
_sax.startPrefixMapping(prefix, uri);
_nsPrefixes.put(prefix, uriStack = new Stack());
uriStack.push(uri);
}
return pushed;
}
/*
* End the scope of a name prefix by popping it from the stack and
* passing the event to the SAX Handler.
*/
private void endPrefixMapping(String prefix)
throws SAXException
{
final Stack uriStack = (Stack) _nsPrefixes.get(prefix);
if (uriStack != null) {
_sax.endPrefixMapping(prefix);
uriStack.pop();
}
}
/**
* If the DOM was created using a DOM 1.0 API, the local name may be
* null. If so, get the local name from the qualified name before
* generating the SAX event.
*/
private static String getLocalName(Node node) {
final String localName = node.getLocalName();
if (localName == null) {
final String qname = node.getNodeName();
final int col = qname.lastIndexOf(':');
return (col > 0) ? qname.substring(col + 1) : qname;
}
return localName;
}
public void parse(InputSource unused) throws IOException, SAXException {
parse(_dom);
}
public void parse() throws IOException, SAXException {
if (_dom != null) {
boolean isIncomplete =
(_dom.getNodeType() != org.w3c.dom.Node.DOCUMENT_NODE);
if (isIncomplete) {
_sax.startDocument();
parse(_dom);
_sax.endDocument();
}
else {
parse(_dom);
}
}
}
/**
* Traverse the DOM and generate SAX events for a handler. A
* startElement() event passes all attributes, including namespace
* declarations.
*/
private void parse(Node node) throws IOException, SAXException {
Node first = null;
if (node == null) return;
switch (node.getNodeType()) {
case Node.ATTRIBUTE_NODE: // handled by ELEMENT_NODE
case Node.DOCUMENT_FRAGMENT_NODE:
case Node.DOCUMENT_TYPE_NODE :
case Node.ENTITY_NODE :
case Node.ENTITY_REFERENCE_NODE:
case Node.NOTATION_NODE :
// These node types are ignored!!!
break;
case Node.CDATA_SECTION_NODE:
final String cdata = node.getNodeValue();
if (_lex != null) {
_lex.startCDATA();
_sax.characters(cdata.toCharArray(), 0, cdata.length());
_lex.endCDATA();
}
else {
// in the case where there is no lex handler, we still
// want the text of the cdate to make its way through.
_sax.characters(cdata.toCharArray(), 0, cdata.length());
}
break;
case Node.COMMENT_NODE: // should be handled!!!
if (_lex != null) {
final String value = node.getNodeValue();
_lex.comment(value.toCharArray(), 0, value.length());
}
break;
case Node.DOCUMENT_NODE:
_sax.setDocumentLocator(this);
_sax.startDocument();
Node next = node.getFirstChild();
while (next != null) {
parse(next);
next = next.getNextSibling();
}
_sax.endDocument();
break;
case Node.ELEMENT_NODE:
String prefix;
Vector pushedPrefixes = new Vector();
final AttributesImpl attrs = new AttributesImpl();
final NamedNodeMap map = node.getAttributes();
final int length = map.getLength();
// Process all namespace declarations
for (int i = 0; i < length; i++) {
final Node attr = map.item(i);
final String qnameAttr = attr.getNodeName();
// Ignore everything but NS declarations here
if (qnameAttr.startsWith(XMLNS_PREFIX)) {
final String uriAttr = attr.getNodeValue();
final int colon = qnameAttr.lastIndexOf(':');
prefix = (colon > 0) ? qnameAttr.substring(colon + 1) : EMPTYSTRING;
if (startPrefixMapping(prefix, uriAttr)) {
pushedPrefixes.addElement(prefix);
}
}
}
// Process all other attributes
for (int i = 0; i < length; i++) {
final Node attr = map.item(i);
String qnameAttr = attr.getNodeName();
// Ignore NS declarations here
if (!qnameAttr.startsWith(XMLNS_PREFIX)) {
final String uriAttr = attr.getNamespaceURI();
final String localNameAttr = getLocalName(attr);
// Uri may be implicitly declared
if (uriAttr != null) {
final int colon = qnameAttr.lastIndexOf(':');
if (colon > 0) {
prefix = qnameAttr.substring(0, colon);
}
else {
// If no prefix for this attr, we need to create
// one because we cannot use the default ns
prefix = BasisLibrary.generatePrefix();
qnameAttr = prefix + ':' + qnameAttr;
}
if (startPrefixMapping(prefix, uriAttr)) {
pushedPrefixes.addElement(prefix);
}
}
// Add attribute to list
attrs.addAttribute(attr.getNamespaceURI(), getLocalName(attr),
qnameAttr, "CDATA", attr.getNodeValue());
}
}
// Now process the element itself
final String qname = node.getNodeName();
final String uri = node.getNamespaceURI();
final String localName = getLocalName(node);
// Uri may be implicitly declared
if (uri != null) {
final int colon = qname.lastIndexOf(':');
prefix = (colon > 0) ? qname.substring(0, colon) : EMPTYSTRING;
if (startPrefixMapping(prefix, uri)) {
pushedPrefixes.addElement(prefix);
}
}
// Generate SAX event to start element
if (_saxImpl != null) {
_saxImpl.startElement(uri, localName, qname, attrs, node);
}
else {
_sax.startElement(uri, localName, qname, attrs);
}
// Traverse all child nodes of the element (if any)
next = node.getFirstChild();
while (next != null) {
parse(next);
next = next.getNextSibling();
}
// Generate SAX event to close element
_sax.endElement(uri, localName, qname);
// Generate endPrefixMapping() for all pushed prefixes
final int nPushedPrefixes = pushedPrefixes.size();
for (int i = 0; i < nPushedPrefixes; i++) {
endPrefixMapping((String) pushedPrefixes.elementAt(i));
}
break;
case Node.PROCESSING_INSTRUCTION_NODE:
_sax.processingInstruction(node.getNodeName(),
node.getNodeValue());
break;
case Node.TEXT_NODE:
final String data = node.getNodeValue();
_sax.characters(data.toCharArray(), 0, data.length());
break;
}
}
/**
* This class is only used internally so this method should never
* be called.
*/
public DTDHandler getDTDHandler() {
return null;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public ErrorHandler getErrorHandler() {
return null;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public boolean getFeature(String name) throws SAXNotRecognizedException,
SAXNotSupportedException
{
return false;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void setFeature(String name, boolean value) throws
SAXNotRecognizedException, SAXNotSupportedException
{
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void parse(String sysId) throws IOException, SAXException {
throw new IOException("This method is not yet implemented.");
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void setDTDHandler(DTDHandler handler) throws NullPointerException {
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void setEntityResolver(EntityResolver resolver) throws
NullPointerException
{
}
/**
* This class is only used internally so this method should never
* be called.
*/
public EntityResolver getEntityResolver() {
return null;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void setErrorHandler(ErrorHandler handler) throws
NullPointerException
{
}
/**
* This class is only used internally so this method should never
* be called.
*/
public void setProperty(String name, Object value) throws
SAXNotRecognizedException, SAXNotSupportedException {
}
/**
* This class is only used internally so this method should never
* be called.
*/
public Object getProperty(String name) throws SAXNotRecognizedException,
SAXNotSupportedException
{
return null;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public int getColumnNumber() {
return 0;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public int getLineNumber() {
return 0;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public String getPublicId() {
return null;
}
/**
* This class is only used internally so this method should never
* be called.
*/
public String getSystemId() {
return null;
}
// Debugging
private String getNodeTypeFromCode(short code) {
String retval = null;
switch (code) {
case Node.ATTRIBUTE_NODE :
retval = "ATTRIBUTE_NODE"; break;
case Node.CDATA_SECTION_NODE :
retval = "CDATA_SECTION_NODE"; break;
case Node.COMMENT_NODE :
retval = "COMMENT_NODE"; break;
case Node.DOCUMENT_FRAGMENT_NODE :
retval = "DOCUMENT_FRAGMENT_NODE"; break;
case Node.DOCUMENT_NODE :
retval = "DOCUMENT_NODE"; break;
case Node.DOCUMENT_TYPE_NODE :
retval = "DOCUMENT_TYPE_NODE"; break;
case Node.ELEMENT_NODE :
retval = "ELEMENT_NODE"; break;
case Node.ENTITY_NODE :
retval = "ENTITY_NODE"; break;
case Node.ENTITY_REFERENCE_NODE :
retval = "ENTITY_REFERENCE_NODE"; break;
case Node.NOTATION_NODE :
retval = "NOTATION_NODE"; break;
case Node.PROCESSING_INSTRUCTION_NODE :
retval = "PROCESSING_INSTRUCTION_NODE"; break;
case Node.TEXT_NODE:
retval = "TEXT_NODE"; break;
}
return retval;
}
}
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