/*
* The Apache Software License, Version 1.1
*
*
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* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
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*/
package org.apache.xml.dtm.ref;
import org.apache.xml.dtm.DTM;
import org.apache.xml.utils.NodeConsumer;
import org.apache.xml.utils.XMLString;
import org.xml.sax.ContentHandler;
import org.xml.sax.ext.LexicalHandler;
/**
* <meta name="usage" content="advanced"/>
* This class does a pre-order walk of the DTM tree, calling a ContentHandler
* interface as it goes. As such, it's more like the Visitor design pattern
* than like the DOM's TreeWalker.
*
* I think normally this class should not be needed, because
* of DTM#dispatchToEvents.
*/
public class DTMTreeWalker
{
/** Local reference to a ContentHandler */
private ContentHandler m_contentHandler = null;
/** DomHelper for this TreeWalker */
protected DTM m_dtm;
/**
* Set the DTM to be traversed.
*
* @param dtm The Document Table Model to be used.
*/
public void setDTM(DTM dtm)
{
m_dtm = dtm;
}
/**
* Get the ContentHandler used for the tree walk.
*
* @return the ContentHandler used for the tree walk
*/
public ContentHandler getcontentHandler()
{
return m_contentHandler;
}
/**
* Set the ContentHandler used for the tree walk.
*
* @param ch the ContentHandler to be the result of the tree walk.
*/
public void setcontentHandler(ContentHandler ch)
{
m_contentHandler = ch;
}
/**
* Constructor.
* @param contentHandler The implemention of the
* contentHandler operation (toXMLString, digest, ...)
*/
public DTMTreeWalker()
{
}
/**
* Constructor.
* @param contentHandler The implemention of the
* contentHandler operation (toXMLString, digest, ...)
*/
public DTMTreeWalker(ContentHandler contentHandler, DTM dtm)
{
this.m_contentHandler = contentHandler;
m_dtm = dtm;
}
/** Perform a non-recursive pre-order/post-order traversal,
* operating as a Visitor. startNode (preorder) and endNode
* (postorder) are invoked for each node as we traverse over them,
* with the result that the node is written out to m_contentHandler.
*
* @param pos Node in the tree at which to start (and end) traversal --
* in other words, the root of the subtree to traverse over.
*
* @throws TransformerException */
public void traverse(int pos) throws org.xml.sax.SAXException
{
// %REVIEW% Why isn't this just traverse(pos,pos)?
int top = pos; // Remember the root of this subtree
while (DTM.NULL != pos)
{
startNode(pos);
int nextNode = m_dtm.getFirstChild(pos);
while (DTM.NULL == nextNode)
{
endNode(pos);
if (top == pos)
break;
nextNode = m_dtm.getNextSibling(pos);
if (DTM.NULL == nextNode)
{
pos = m_dtm.getParent(pos);
if ((DTM.NULL == pos) || (top == pos))
{
// %REVIEW% This condition isn't tested in traverse(pos,top)
// -- bug?
if (DTM.NULL != pos)
endNode(pos);
nextNode = DTM.NULL;
break;
}
}
}
pos = nextNode;
}
}
/** Perform a non-recursive pre-order/post-order traversal,
* operating as a Visitor. startNode (preorder) and endNode
* (postorder) are invoked for each node as we traverse over them,
* with the result that the node is written out to m_contentHandler.
*
* @param pos Node in the tree where to start traversal
* @param top Node in the tree where to end traversal.
* If top==DTM.NULL, run through end of document.
*
* @throws TransformerException
*/
public void traverse(int pos, int top) throws org.xml.sax.SAXException
{
// %OPT% Can we simplify the loop conditionals by adding:
// if(top==DTM.NULL) top=0
// -- or by simply ignoring this case and relying on the fact that
// pos will never equal DTM.NULL until we're ready to exit?
while (DTM.NULL != pos)
{
startNode(pos);
int nextNode = m_dtm.getFirstChild(pos);
while (DTM.NULL == nextNode)
{
endNode(pos);
if ((DTM.NULL != top) && top == pos)
break;
nextNode = m_dtm.getNextSibling(pos);
if (DTM.NULL == nextNode)
{
pos = m_dtm.getParent(pos);
if ((DTM.NULL == pos) || ((DTM.NULL != top) && (top == pos)))
{
nextNode = DTM.NULL;
break;
}
}
}
pos = nextNode;
}
}
/** Flag indicating whether following text to be processed is raw text */
boolean nextIsRaw = false;
/**
* Optimized dispatch of characters.
*/
private final void dispatachChars(int node)
throws org.xml.sax.SAXException
{
m_dtm.dispatchCharactersEvents(node, m_contentHandler, false);
}
/**
* Start processing given node
*
*
* @param node Node to process
*
* @throws org.xml.sax.SAXException
*/
protected void startNode(int node) throws org.xml.sax.SAXException
{
if (m_contentHandler instanceof NodeConsumer)
{
// %TBD%
// ((NodeConsumer) m_contentHandler).setOriginatingNode(node);
}
switch (m_dtm.getNodeType(node))
{
case DTM.COMMENT_NODE :
{
XMLString data = m_dtm.getStringValue(node);
if (m_contentHandler instanceof LexicalHandler)
{
LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
data.dispatchAsComment(lh);
}
}
break;
case DTM.DOCUMENT_FRAGMENT_NODE :
// ??;
break;
case DTM.DOCUMENT_NODE :
this.m_contentHandler.startDocument();
break;
case DTM.ELEMENT_NODE :
DTM dtm = m_dtm;
for (int nsn = dtm.getFirstNamespaceNode(node, true); DTM.NULL != nsn;
nsn = dtm.getNextNamespaceNode(node, nsn, true))
{
// String prefix = dtm.getPrefix(nsn);
String prefix = dtm.getNodeNameX(nsn);
this.m_contentHandler.startPrefixMapping(prefix, dtm.getNodeValue(nsn));
}
// System.out.println("m_dh.getNamespaceOfNode(node): "+m_dh.getNamespaceOfNode(node));
// System.out.println("m_dh.getLocalNameOfNode(node): "+m_dh.getLocalNameOfNode(node));
String ns = dtm.getNamespaceURI(node);
if(null == ns)
ns = "";
// %OPT% !!
org.xml.sax.helpers.AttributesImpl attrs =
new org.xml.sax.helpers.AttributesImpl();
for (int i = dtm.getFirstAttribute(node);
i != DTM.NULL;
i = dtm.getNextAttribute(i))
{
attrs.addAttribute(dtm.getNamespaceURI(i),
dtm.getLocalName(i),
dtm.getNodeName(i),
"CDATA",
dtm.getNodeValue(i));
}
this.m_contentHandler.startElement(ns,
m_dtm.getLocalName(node),
m_dtm.getNodeName(node),
attrs);
break;
case DTM.PROCESSING_INSTRUCTION_NODE :
{
String name = m_dtm.getNodeName(node);
// String data = pi.getData();
if (name.equals("xslt-next-is-raw"))
{
nextIsRaw = true;
}
else
{
this.m_contentHandler.processingInstruction(name,
m_dtm.getNodeValue(node));
}
}
break;
case DTM.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 DTM.TEXT_NODE :
{
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 DTM.ENTITY_REFERENCE_NODE :
{
if (m_contentHandler instanceof LexicalHandler)
{
((LexicalHandler) this.m_contentHandler).startEntity(
m_dtm.getNodeName(node));
}
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(int node) throws org.xml.sax.SAXException
{
switch (m_dtm.getNodeType(node))
{
case DTM.DOCUMENT_NODE :
this.m_contentHandler.endDocument();
break;
case DTM.ELEMENT_NODE :
String ns = m_dtm.getNamespaceURI(node);
if(null == ns)
ns = "";
this.m_contentHandler.endElement(ns,
m_dtm.getLocalName(node),
m_dtm.getNodeName(node));
for (int nsn = m_dtm.getFirstNamespaceNode(node, true); DTM.NULL != nsn;
nsn = m_dtm.getNextNamespaceNode(node, nsn, true))
{
// String prefix = m_dtm.getPrefix(nsn);
String prefix = m_dtm.getNodeNameX(nsn);
this.m_contentHandler.endPrefixMapping(prefix);
}
break;
case DTM.CDATA_SECTION_NODE :
break;
case DTM.ENTITY_REFERENCE_NODE :
{
if (m_contentHandler instanceof LexicalHandler)
{
LexicalHandler lh = ((LexicalHandler) this.m_contentHandler);
lh.endEntity(m_dtm.getNodeName(node));
}
}
break;
default :
}
}
} //TreeWalker