Java example source code file (TreeWalker.java)
The TreeWalker.java Java example source code
/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 1999-2004 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: TreeWalker.java,v 1.2.4.1 2005/09/15 08:15:59 suresh_emailid Exp $
*/
package com.sun.org.apache.xml.internal.utils;
import com.sun.org.apache.xalan.internal.utils.SecuritySupport;
import java.io.File;
import org.w3c.dom.Comment;
import org.w3c.dom.Element;
import org.w3c.dom.EntityReference;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.ext.LexicalHandler;
import org.xml.sax.helpers.LocatorImpl;
/**
* This class does a pre-order walk of the DOM tree, calling a ContentHandler
* interface as it goes.
* @xsl.usage advanced
*/
public class TreeWalker
{
/** Local reference to a ContentHandler */
private ContentHandler m_contentHandler = null;
// ARGHH!! JAXP Uses Xerces without setting the namespace processing to ON!
// DOM2Helper m_dh = new DOM2Helper();
/** DomHelper for this TreeWalker */
protected DOMHelper m_dh;
/** Locator object for this TreeWalker */
private LocatorImpl m_locator = new LocatorImpl();
/**
* Get the ContentHandler used for the tree walk.
*
* @return the ContentHandler used for the tree walk
*/
public ContentHandler getContentHandler()
{
return m_contentHandler;
}
/**
* Get the ContentHandler used for the tree walk.
*
* @return the ContentHandler used for the tree walk
*/
public void setContentHandler(ContentHandler ch)
{
m_contentHandler = ch;
}
/**
* Constructor.
* @param contentHandler The implemention of the
* @param systemId System identifier for the document.
* contentHandler operation (toXMLString, digest, ...)
*/
public TreeWalker(ContentHandler contentHandler, DOMHelper dh, String systemId)
{
this.m_contentHandler = contentHandler;
m_contentHandler.setDocumentLocator(m_locator);
if (systemId != null)
m_locator.setSystemId(systemId);
else {
try {
// Bug see Bugzilla 26741
m_locator.setSystemId(SecuritySupport.getSystemProperty("user.dir") + File.separator + "dummy.xsl");
}
catch (SecurityException se) {// user.dir not accessible from applet
}
}
m_dh = dh;
}
/**
* Constructor.
* @param contentHandler The implemention of the
* contentHandler operation (toXMLString, digest, ...)
*/
public TreeWalker(ContentHandler contentHandler, DOMHelper dh)
{
this.m_contentHandler = contentHandler;
m_contentHandler.setDocumentLocator(m_locator);
try {
// Bug see Bugzilla 26741
m_locator.setSystemId(SecuritySupport.getSystemProperty("user.dir") + File.separator + "dummy.xsl");
}
catch (SecurityException se){// user.dir not accessible from applet
}
m_dh = dh;
}
/**
* Constructor.
* @param contentHandler The implemention of the
* contentHandler operation (toXMLString, digest, ...)
*/
public TreeWalker(ContentHandler contentHandler)
{
this.m_contentHandler = contentHandler;
if (m_contentHandler != null)
m_contentHandler.setDocumentLocator(m_locator);
try {
// Bug see Bugzilla 26741
m_locator.setSystemId(SecuritySupport.getSystemProperty("user.dir") + File.separator + "dummy.xsl");
}
catch (SecurityException se){// user.dir not accessible from applet
}
m_dh = new DOM2Helper();
}
/**
* Perform a pre-order traversal non-recursive style.
*
* Note that TreeWalker assumes that the subtree is intended to represent
* a complete (though not necessarily well-formed) document and, during a
* traversal, startDocument and endDocument will always be issued to the
* SAX listener.
*
* @param pos Node in the tree where to start traversal
*
* @throws TransformerException
*/
public void traverse(Node pos) throws org.xml.sax.SAXException
{
this.m_contentHandler.startDocument();
traverseFragment(pos);
this.m_contentHandler.endDocument();
}
/**
* Perform a pre-order traversal non-recursive style.
*
* In contrast to the traverse() method this method will not issue
* startDocument() and endDocument() events to the SAX listener.
*
* @param pos Node in the tree where to start traversal
*
* @throws TransformerException
*/
public void traverseFragment(Node pos) throws org.xml.sax.SAXException
{
Node top = pos;
while (null != pos)
{
startNode(pos);
Node nextNode = pos.getFirstChild();
while (null == nextNode)
{
endNode(pos);
if (top.equals(pos))
break;
nextNode = pos.getNextSibling();
if (null == nextNode)
{
pos = pos.getParentNode();
if ((null == pos) || (top.equals(pos)))
{
if (null != pos)
endNode(pos);
nextNode = null;
break;
}
}
}
pos = nextNode;
}
}
/**
* Perform a pre-order traversal non-recursive style.
* Note that TreeWalker assumes that the subtree is intended to represent
* a complete (though not necessarily well-formed) document and, during a
* traversal, startDocument and endDocument will always be issued to the
* SAX listener.
*
* @param pos Node in the tree where to start traversal
* @param top Node in the tree where to end traversal
*
* @throws TransformerException
*/
public void traverse(Node pos, Node top) throws org.xml.sax.SAXException
{
this.m_contentHandler.startDocument();
while (null != pos)
{
startNode(pos);
Node nextNode = pos.getFirstChild();
while (null == nextNode)
{
endNode(pos);
if ((null != top) && top.equals(pos))
break;
nextNode = pos.getNextSibling();
if (null == nextNode)
{
pos = pos.getParentNode();
if ((null == pos) || ((null != top) && top.equals(pos)))
{
nextNode = null;
break;
}
}
}
pos = nextNode;
}
this.m_contentHandler.endDocument();
}
/** Flag indicating whether following text to be processed is raw text */
boolean nextIsRaw = false;
/**
* Optimized dispatch of characters.
*/
private final void dispatachChars(Node node)
throws org.xml.sax.SAXException
{
if(m_contentHandler instanceof com.sun.org.apache.xml.internal.dtm.ref.dom2dtm.DOM2DTM.CharacterNodeHandler)
{
((com.sun.org.apache.xml.internal.dtm.ref.dom2dtm.DOM2DTM.CharacterNodeHandler)m_contentHandler).characters(node);
}
else
{
String data = ((Text) node).getData();
this.m_contentHandler.characters(data.toCharArray(), 0, data.length());
}
}
/**
* Start processing given node
*
*
* @param node Node to process
*
* @throws org.xml.sax.SAXException
*/
protected void startNode(Node node) throws org.xml.sax.SAXException
{
if (m_contentHandler instanceof NodeConsumer)
{
((NodeConsumer) m_contentHandler).setOriginatingNode(node);
}
if (node instanceof Locator)
{
Locator loc = (Locator)node;
m_locator.setColumnNumber(loc.getColumnNumber());
m_locator.setLineNumber(loc.getLineNumber());
m_locator.setPublicId(loc.getPublicId());
m_locator.setSystemId(loc.getSystemId());
}
else
{
m_locator.setColumnNumber(0);
m_locator.setLineNumber(0);
}
switch (node.getNodeType())
{
case Node.COMMENT_NODE :
{
String data = ((Comment) node).getData();
if (m_contentHandler instanceof LexicalHandler)
{
LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
lh.comment(data.toCharArray(), 0, data.length());
}
}
break;
case Node.DOCUMENT_FRAGMENT_NODE :
// ??;
break;
case Node.DOCUMENT_NODE :
break;
case Node.ELEMENT_NODE :
NamedNodeMap atts = ((Element) node).getAttributes();
int nAttrs = atts.getLength();
// System.out.println("TreeWalker#startNode: "+node.getNodeName());
for (int i = 0; i < nAttrs; i++)
{
Node attr = atts.item(i);
String attrName = attr.getNodeName();
// System.out.println("TreeWalker#startNode: attr["+i+"] = "+attrName+", "+attr.getNodeValue());
if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
{
// System.out.println("TreeWalker#startNode: attr["+i+"] = "+attrName+", "+attr.getNodeValue());
int index;
// Use "" instead of null, as Xerces likes "" for the
// name of the default namespace. Fix attributed
// to "Steven Murray" <smurray@ebt.com>.
String prefix = (index = attrName.indexOf(":")) < 0
? "" : attrName.substring(index + 1);
this.m_contentHandler.startPrefixMapping(prefix,
attr.getNodeValue());
}
}
// System.out.println("m_dh.getNamespaceOfNode(node): "+m_dh.getNamespaceOfNode(node));
// System.out.println("m_dh.getLocalNameOfNode(node): "+m_dh.getLocalNameOfNode(node));
String ns = m_dh.getNamespaceOfNode(node);
if(null == ns)
ns = "";
this.m_contentHandler.startElement(ns,
m_dh.getLocalNameOfNode(node),
node.getNodeName(),
new AttList(atts, m_dh));
break;
case Node.PROCESSING_INSTRUCTION_NODE :
{
ProcessingInstruction pi = (ProcessingInstruction) node;
String name = pi.getNodeName();
// String data = pi.getData();
if (name.equals("xslt-next-is-raw"))
{
nextIsRaw = true;
}
else
{
this.m_contentHandler.processingInstruction(pi.getNodeName(),
pi.getData());
}
}
break;
case Node.CDATA_SECTION_NODE :
{
boolean isLexH = (m_contentHandler instanceof LexicalHandler);
LexicalHandler lh = isLexH
? ((LexicalHandler) this.m_contentHandler) : null;
if (isLexH)
{
lh.startCDATA();
}
dispatachChars(node);
{
if (isLexH)
{
lh.endCDATA();
}
}
}
break;
case Node.TEXT_NODE :
{
//String data = ((Text) node).getData();
if (nextIsRaw)
{
nextIsRaw = false;
m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
dispatachChars(node);
m_contentHandler.processingInstruction(javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
}
else
{
dispatachChars(node);
}
}
break;
case Node.ENTITY_REFERENCE_NODE :
{
EntityReference eref = (EntityReference) node;
if (m_contentHandler instanceof LexicalHandler)
{
((LexicalHandler) this.m_contentHandler).startEntity(
eref.getNodeName());
}
else
{
// warning("Can not output entity to a pure SAX ContentHandler");
}
}
break;
default :
}
}
/**
* End processing of given node
*
*
* @param node Node we just finished processing
*
* @throws org.xml.sax.SAXException
*/
protected void endNode(Node node) throws org.xml.sax.SAXException
{
switch (node.getNodeType())
{
case Node.DOCUMENT_NODE :
break;
case Node.ELEMENT_NODE :
String ns = m_dh.getNamespaceOfNode(node);
if(null == ns)
ns = "";
this.m_contentHandler.endElement(ns,
m_dh.getLocalNameOfNode(node),
node.getNodeName());
NamedNodeMap atts = ((Element) node).getAttributes();
int nAttrs = atts.getLength();
for (int i = 0; i < nAttrs; i++)
{
Node attr = atts.item(i);
String attrName = attr.getNodeName();
if (attrName.equals("xmlns") || attrName.startsWith("xmlns:"))
{
int index;
// Use "" instead of null, as Xerces likes "" for the
// name of the default namespace. Fix attributed
// to "Steven Murray" <smurray@ebt.com>.
String prefix = (index = attrName.indexOf(":")) < 0
? "" : attrName.substring(index + 1);
this.m_contentHandler.endPrefixMapping(prefix);
}
}
break;
case Node.CDATA_SECTION_NODE :
break;
case Node.ENTITY_REFERENCE_NODE :
{
EntityReference eref = (EntityReference) node;
if (m_contentHandler instanceof LexicalHandler)
{
LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
lh.endEntity(eref.getNodeName());
}
}
break;
default :
}
}
} //TreeWalker
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