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	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You 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.
	*/

	package com.sun.org.apache.xerces.internal.dom;

	import org.w3c.dom.DOMException;
	import org.w3c.dom.Node;
	import org.w3c.dom.traversal.NodeFilter;
	import org.w3c.dom.traversal.TreeWalker;

	/** This class implements the TreeWalker interface.
	*
	* @xerces.internal
	*
	*/

	public class TreeWalkerImpl implements TreeWalker {

	//
	// Data
	//

	/** When TRUE, the children of entites references are returned in the iterator. */
	private boolean fEntityReferenceExpansion = false;
	/** The whatToShow mask. */
	int fWhatToShow = NodeFilter.SHOW_ALL;
	/** The NodeFilter reference. */
	NodeFilter fNodeFilter;
	/** The current Node. */
	Node fCurrentNode;
	/** The root Node. */
	Node fRoot;

	//
	// Implementation Note: No state is kept except the data above
	// (fWhatToShow, fNodeFilter, fCurrentNode, fRoot) such that
	// setters could be created for these data values and the
	// implementation will still work.


	//
	// Constructor
	//

	/** Public constructor */
	public TreeWalkerImpl(Node root,
	int whatToShow,
	NodeFilter nodeFilter,
	boolean entityReferenceExpansion) {
	fCurrentNode = root;
	fRoot = root;
	fWhatToShow = whatToShow;
	fNodeFilter = nodeFilter;
	fEntityReferenceExpansion = entityReferenceExpansion;
	}

	public Node getRoot() {
	return fRoot;
	}

	/** Return the whatToShow value */
	public int getWhatToShow() {
	return fWhatToShow;
	}

	public void setWhatShow(int whatToShow){
	fWhatToShow = whatToShow;
	}
	/** Return the NodeFilter */
	public NodeFilter getFilter() {
	return fNodeFilter;
	}

	/** Return whether children entity references are included in the iterator. */
	public boolean getExpandEntityReferences() {
	return fEntityReferenceExpansion;
	}

	/** Return the current Node. */
	public Node getCurrentNode() {
	return fCurrentNode;
	}
	/** Return the current Node. */
	public void setCurrentNode(Node node) {
	if (node == null) {
	String msg = DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "NOT_SUPPORTED_ERR", null);
	throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
	}

	fCurrentNode = node;
	}

	/** Return the parent Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node parentNode() {

	if (fCurrentNode == null) return null;

	Node node = getParentNode(fCurrentNode);
	if (node !=null) {
	fCurrentNode = node;
	}
	return node;

	}

	/** Return the first child Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node firstChild() {

	if (fCurrentNode == null) return null;

	Node node = getFirstChild(fCurrentNode);
	if (node !=null) {
	fCurrentNode = node;
	}
	return node;
	}
	/** Return the last child Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node lastChild() {

	if (fCurrentNode == null) return null;

	Node node = getLastChild(fCurrentNode);
	if (node !=null) {
	fCurrentNode = node;
	}
	return node;
	}

	/** Return the previous sibling Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node previousSibling() {

	if (fCurrentNode == null) return null;

	Node node = getPreviousSibling(fCurrentNode);
	if (node !=null) {
	fCurrentNode = node;
	}
	return node;
	}

	/** Return the next sibling Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node nextSibling(){
	if (fCurrentNode == null) return null;

	Node node = getNextSibling(fCurrentNode);
	if (node !=null) {
	fCurrentNode = node;
	}
	return node;
	}

	/** Return the previous Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node previousNode() {
	Node result;

	if (fCurrentNode == null) return null;

	// get sibling
	result = getPreviousSibling(fCurrentNode);
	if (result == null) {
	result = getParentNode(fCurrentNode);
	if (result != null) {
	fCurrentNode = result;
	return fCurrentNode;
	}
	return null;
	}

	// get the lastChild of result.
	Node lastChild = getLastChild(result);

	Node prev = lastChild ;
	while (lastChild != null) {
	prev = lastChild ;
	lastChild = getLastChild(prev) ;
	}

	lastChild = prev ;

	// if there is a lastChild which passes filters return it.
	if (lastChild != null) {
	fCurrentNode = lastChild;
	return fCurrentNode;
	}

	// otherwise return the previous sibling.
	if (result != null) {
	fCurrentNode = result;
	return fCurrentNode;
	}

	// otherwise return null.
	return null;
	}

	/** Return the next Node from the current node,
	* after applying filter, whatToshow.
	* If result is not null, set the current Node.
	*/
	public Node nextNode() {

	if (fCurrentNode == null) return null;

	Node result = getFirstChild(fCurrentNode);

	if (result != null) {
	fCurrentNode = result;
	return result;
	}

	result = getNextSibling(fCurrentNode);

	if (result != null) {
	fCurrentNode = result;
	return result;
	}

	// return parent's 1st sibling.
	Node parent = getParentNode(fCurrentNode);
	while (parent != null) {
	result = getNextSibling(parent);
	if (result != null) {
	fCurrentNode = result;
	return result;
	} else {
	parent = getParentNode(parent);
	}
	}

	// end , return null
	return null;
	}

	/** Internal function.
	* Return the parent Node, from the input node
	* after applying filter, whatToshow.
	* The current node is not consulted or set.
	*/
	Node getParentNode(Node node) {

	if (node == null \|\| node == fRoot) return null;

	Node newNode = node.getParentNode();
	if (newNode == null) return null;

	int accept = acceptNode(newNode);

	if (accept == NodeFilter.FILTER_ACCEPT)
	return newNode;
	else
	//if (accept == NodeFilter.SKIP_NODE) // and REJECT too.
	{
	return getParentNode(newNode);
	}


	}

	/** Internal function.
	* Return the nextSibling Node, from the input node
	* after applying filter, whatToshow.
	* The current node is not consulted or set.
	*/
	Node getNextSibling(Node node) {
	return getNextSibling(node, fRoot);
	}

	/** Internal function.
	* Return the nextSibling Node, from the input node
	* after applying filter, whatToshow.
	* NEVER TRAVERSES ABOVE THE SPECIFIED ROOT NODE.
	* The current node is not consulted or set.
	*/
	Node getNextSibling(Node node, Node root) {

	if (node == null \|\| node == root) return null;

	Node newNode = node.getNextSibling();
	if (newNode == null) {

	newNode = node.getParentNode();

	if (newNode == null \|\| newNode == root) return null;

	int parentAccept = acceptNode(newNode);

	if (parentAccept==NodeFilter.FILTER_SKIP) {
	return getNextSibling(newNode, root);
	}

	return null;
	}

	int accept = acceptNode(newNode);

	if (accept == NodeFilter.FILTER_ACCEPT)
	return newNode;
	else
	if (accept == NodeFilter.FILTER_SKIP) {
	Node fChild = getFirstChild(newNode);
	if (fChild == null) {
	return getNextSibling(newNode, root);
	}
	return fChild;
	}
	else
	//if (accept == NodeFilter.REJECT_NODE)
	{
	return getNextSibling(newNode, root);
	}

	} // getNextSibling(Node node) {

	/** Internal function.
	* Return the previous sibling Node, from the input node
	* after applying filter, whatToshow.
	* The current node is not consulted or set.
	*/
	Node getPreviousSibling(Node node) {
	return getPreviousSibling(node, fRoot);
	}

	/** Internal function.
	* Return the previousSibling Node, from the input node
	* after applying filter, whatToshow.
	* NEVER TRAVERSES ABOVE THE SPECIFIED ROOT NODE.
	* The current node is not consulted or set.
	*/
	Node getPreviousSibling(Node node, Node root) {

	if (node == null \|\| node == root) return null;

	Node newNode = node.getPreviousSibling();
	if (newNode == null) {

	newNode = node.getParentNode();
	if (newNode == null \|\| newNode == root) return null;

	int parentAccept = acceptNode(newNode);

	if (parentAccept==NodeFilter.FILTER_SKIP) {
	return getPreviousSibling(newNode, root);
	}

	return null;
	}

	int accept = acceptNode(newNode);

	if (accept == NodeFilter.FILTER_ACCEPT)
	return newNode;
	else
	if (accept == NodeFilter.FILTER_SKIP) {
	Node fChild = getLastChild(newNode);
	if (fChild == null) {
	return getPreviousSibling(newNode, root);
	}
	return fChild;
	}
	else
	//if (accept == NodeFilter.REJECT_NODE)
	{
	return getPreviousSibling(newNode, root);
	}

	} // getPreviousSibling(Node node) {

	/** Internal function.
	* Return the first child Node, from the input node
	* after applying filter, whatToshow.
	* The current node is not consulted or set.
	*/
	Node getFirstChild(Node node) {
	if (node == null) return null;

	if ( !fEntityReferenceExpansion
	&& node.getNodeType() == Node.ENTITY_REFERENCE_NODE)
	return null;
	Node newNode = node.getFirstChild();
	if (newNode == null) return null;
	int accept = acceptNode(newNode);

	if (accept == NodeFilter.FILTER_ACCEPT)
	return newNode;
	else
	if (accept == NodeFilter.FILTER_SKIP
	&& newNode.hasChildNodes())
	{
	Node fChild = getFirstChild(newNode);

	if (fChild == null) {
	return getNextSibling(newNode, node);
	}
	return fChild;
	}
	else
	//if (accept == NodeFilter.REJECT_NODE)
	{
	return getNextSibling(newNode, node);
	}


	}

	/** Internal function.
	* Return the last child Node, from the input node
	* after applying filter, whatToshow.
	* The current node is not consulted or set.
	*/
	Node getLastChild(Node node) {

	if (node == null) return null;

	if ( !fEntityReferenceExpansion
	&& node.getNodeType() == Node.ENTITY_REFERENCE_NODE)
	return null;

	Node newNode = node.getLastChild();
	if (newNode == null) return null;

	int accept = acceptNode(newNode);

	if (accept == NodeFilter.FILTER_ACCEPT)
	return newNode;
	else
	if (accept == NodeFilter.FILTER_SKIP
	&& newNode.hasChildNodes())
	{
	Node lChild = getLastChild(newNode);
	if (lChild == null) {
	return getPreviousSibling(newNode, node);
	}
	return lChild;
	}
	else
	//if (accept == NodeFilter.REJECT_NODE)
	{
	return getPreviousSibling(newNode, node);
	}


	}

	/** Internal function.
	* The node whatToShow and the filter are combined into one result. */
	short acceptNode(Node node) {
	/***
	7.1.2.4. Filters and whatToShow flags

	Iterator and TreeWalker apply whatToShow flags before applying Filters. If a node is rejected by the
	active whatToShow flags, a Filter will not be called to evaluate that node. When a node is rejected by
	the active whatToShow flags, children of that node will still be considered, and Filters may be called to
	evaluate them.
	***/

	if (fNodeFilter == null) {
	if ( ( fWhatToShow & (1 << node.getNodeType()-1)) != 0) {
	return NodeFilter.FILTER_ACCEPT;
	} else {
	return NodeFilter.FILTER_SKIP;
	}
	} else {
	if ((fWhatToShow & (1 << node.getNodeType()-1)) != 0 ) {
	return fNodeFilter.acceptNode(node);
	} else {
	// What to show has failed. See above excerpt from spec.
	// Equivalent to FILTER_SKIP.
	return NodeFilter.FILTER_SKIP;
	}
	}
	}
	}

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