org.apache.xml.dtm.ref.DTMChildIterNodeList Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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.
*/
/*
* $Id: DTMChildIterNodeList.java 468653 2006-10-28 07:07:05Z minchau $
*/
package org.apache.xml.dtm.ref;
import org.apache.xml.dtm.DTM;
import org.w3c.dom.Node;
/**
* DTMNodeList gives us an implementation of the DOM's
* NodeList interface wrapped around a DTM Iterator. The author
* considers this something of an abominations, since NodeList was not
* intended to be a general purpose "list of nodes" API and is
* generally considered by the DOM WG to have be a mistake... but I'm
* told that some of the XPath/XSLT folks say they must have this
* solution.
*
* Please note that this is not necessarily equivlaent to a DOM
* NodeList operating over the same document. In particular:
*
*
* - If there are several Text nodes in logical succession (ie,
* across CDATASection and EntityReference boundaries), we will return
* only the first; the caller is responsible for stepping through
* them.
* (%REVIEW% Provide a convenience routine here to assist, pending
* proposed DOM Level 3 getAdjacentText() operation?)
*
* - Since the whole XPath/XSLT architecture assumes that the source
* document is not altered while we're working with it, we do not
* promise to implement the DOM NodeList's "live view" response to
* document mutation.
*
*
*
* State: In progress!!
* */
public class DTMChildIterNodeList extends DTMNodeListBase {
private int m_firstChild;
private DTM m_parentDTM;
//================================================================
// Methods unique to this class
private DTMChildIterNodeList() {
}
/**
* Public constructor: Create a NodeList to support
* DTMNodeProxy.getChildren().
*
* Unfortunately AxisIterators and DTMIterators don't share an API,
* so I can't use the existing Axis.CHILD iterator. Rather than
* create Yet Another Class, let's set up a special case of this
* one.
*
* @param parentDTM The DTM containing this node
* @param parentHandle DTM node-handle integer
*
*/
public DTMChildIterNodeList(DTM parentDTM,int parentHandle) {
m_parentDTM=parentDTM;
m_firstChild=parentDTM.getFirstChild(parentHandle);
}
//================================================================
// org.w3c.dom.NodeList API follows
/**
* Returns the indexth item in the collection. If
* index is greater than or equal to the number of nodes in
* the list, this returns null.
* @param index Index into the collection.
* @return The node at the indexth position in the
* NodeList, or null if that is not a valid
* index.
*/
public Node item(int index) {
int handle=m_firstChild;
while(--index>=0 && handle!=DTM.NULL) {
handle=m_parentDTM.getNextSibling(handle);
}
if (handle == DTM.NULL) {
return null;
}
return m_parentDTM.getNode(handle);
}
/**
* The number of nodes in the list. The range of valid child node indices
* is 0 to length-1 inclusive.
*/
public int getLength() {
int count=0;
for (int handle=m_firstChild;
handle!=DTM.NULL;
handle=m_parentDTM.getNextSibling(handle)) {
++count;
}
return count;
}
}