org.apache.xml.security.signature.reference.ReferenceSubTreeData Maven / Gradle / Ivy
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/**
* 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.
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
*/
/*
* $Id$
*/
package org.apache.xml.security.signature.reference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
/**
* A representation of a ReferenceNodeSetData type containing a node-set.
* This is a subtype of NodeSetData that represents a dereferenced
* same-document URI as the root of a subdocument. The main reason is
* for efficiency and performance, as some transforms can operate
* directly on the subdocument and there is no need to convert it
* first to an XPath node-set.
*/
public class ReferenceSubTreeData implements ReferenceNodeSetData {
private boolean excludeComments;
private Node root;
public ReferenceSubTreeData(Node root, boolean excludeComments) {
this.root = root;
this.excludeComments = excludeComments;
}
public Iterator iterator() {
return new DelayedNodeIterator(root, excludeComments);
}
public Node getRoot() {
return root;
}
public boolean excludeComments() {
return excludeComments;
}
/**
* This is an Iterator that contains a backing node-set that is
* not populated until the caller first attempts to advance the iterator.
*/
static class DelayedNodeIterator implements Iterator {
private Node root;
private List nodeSet;
private ListIterator li;
private boolean withComments;
DelayedNodeIterator(Node root, boolean excludeComments) {
this.root = root;
this.withComments = !excludeComments;
}
public boolean hasNext() {
if (nodeSet == null) {
nodeSet = dereferenceSameDocumentURI(root);
li = nodeSet.listIterator();
}
return li.hasNext();
}
public Node next() {
if (nodeSet == null) {
nodeSet = dereferenceSameDocumentURI(root);
li = nodeSet.listIterator();
}
if (li.hasNext()) {
return li.next();
} else {
throw new NoSuchElementException();
}
}
public void remove() {
throw new UnsupportedOperationException();
}
/**
* Dereferences a same-document URI fragment.
*
* @param node the node (document or element) referenced by the
* URI fragment. If null, returns an empty set.
* @return a set of nodes (minus any comment nodes)
*/
private List dereferenceSameDocumentURI(Node node) {
List nodeSet = new ArrayList();
if (node != null) {
nodeSetMinusCommentNodes(node, nodeSet, null);
}
return nodeSet;
}
/**
* Recursively traverses the subtree, and returns an XPath-equivalent
* node-set of all nodes traversed, excluding any comment nodes,
* if specified.
*
* @param node the node to traverse
* @param nodeSet the set of nodes traversed so far
* @param the previous sibling node
*/
@SuppressWarnings("fallthrough")
private void nodeSetMinusCommentNodes(Node node, List nodeSet,
Node prevSibling)
{
switch (node.getNodeType()) {
case Node.ELEMENT_NODE :
nodeSet.add(node);
NamedNodeMap attrs = node.getAttributes();
if (attrs != null) {
for (int i = 0, len = attrs.getLength(); i < len; i++) {
nodeSet.add(attrs.item(i));
}
}
Node pSibling = null;
for (Node child = node.getFirstChild(); child != null;
child = child.getNextSibling()) {
nodeSetMinusCommentNodes(child, nodeSet, pSibling);
pSibling = child;
}
break;
case Node.DOCUMENT_NODE :
pSibling = null;
for (Node child = node.getFirstChild(); child != null;
child = child.getNextSibling()) {
nodeSetMinusCommentNodes(child, nodeSet, pSibling);
pSibling = child;
}
break;
case Node.TEXT_NODE :
case Node.CDATA_SECTION_NODE:
// emulate XPath which only returns the first node in
// contiguous text/cdata nodes
if (prevSibling != null &&
(prevSibling.getNodeType() == Node.TEXT_NODE ||
prevSibling.getNodeType() == Node.CDATA_SECTION_NODE)) {
return;
}
nodeSet.add(node);
break;
case Node.PROCESSING_INSTRUCTION_NODE :
nodeSet.add(node);
break;
case Node.COMMENT_NODE:
if (withComments) {
nodeSet.add(node);
}
}
}
}
}