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Xerces2 is the next generation of high performance, fully compliant XML parsers in the Apache Xerces family.
This new version of Xerces introduces the Xerces Native Interface (XNI), a complete framework for building
parser components and configurations that is extremely modular and easy to program. The Apache Xerces2 parser is
the reference implementation of XNI but other parser components, configurations, and parsers can be written
using the Xerces Native Interface. For complete design and implementation documents, refer to the XNI Manual.
Xerces2 is a fully conforming XML Schema 1.0 processor. A partial experimental implementation of the XML Schema
1.1 Structures and Datatypes Working Drafts (December 2009) and an experimental implementation of the XML Schema
Definition Language (XSD): Component Designators (SCD) Candidate Recommendation (January 2010) are provided for
evaluation. For more information, refer to the XML Schema page. Xerces2 also provides a complete implementation
of the Document Object Model Level 3 Core and Load/Save W3C Recommendations and provides a complete
implementation of the XML Inclusions (XInclude) W3C Recommendation. It also provides support for OASIS XML
Catalogs v1.1. Xerces2 is able to parse documents written according to the XML 1.1 Recommendation, except that
it does not yet provide an option to enable normalization checking as described in section 2.13 of this
specification. It also handles namespaces according to the XML Namespaces 1.1 Recommendation, and will correctly
serialize XML 1.1 documents if the DOM level 3 load/save APIs are in use.
/*
* 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 org.apache.xerces.dom;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
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
*
* @version $Id: TreeWalkerImpl.java 536630 2007-05-09 19:37:05Z mrglavas $
*/
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;
/** Use Node.isSameNode() to check if one node is the same as another. */
private boolean fUseIsSameNode;
//
// 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;
fUseIsSameNode = useIsSameNode(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 || isSameNode(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 || isSameNode(node, root)) return null;
Node newNode = node.getNextSibling();
if (newNode == null) {
newNode = node.getParentNode();
if (newNode == null || isSameNode(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 || isSameNode(node, root)) return null;
Node newNode = node.getPreviousSibling();
if (newNode == null) {
newNode = node.getParentNode();
if (newNode == null || isSameNode(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;
}
}
}
/**
* Use isSameNode() for testing node identity if the DOM implementation
* supports DOM Level 3 core and it isn't the Xerces implementation.
*/
private boolean useIsSameNode(Node node) {
if (node instanceof NodeImpl) {
return false;
}
Document doc = node.getNodeType() == Node.DOCUMENT_NODE
? (Document) node : node.getOwnerDocument();
return (doc != null && doc.getImplementation().hasFeature("Core", "3.0"));
}
/**
* Returns true if m is the same node n.
*/
private boolean isSameNode(Node m, Node n) {
return (fUseIsSameNode) ? m.isSameNode(n) : m == n;
}
}