/*
* 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.
*/
/*
* $Id: DTMAxisIterNodeList.java 468653 2006-10-28 07:07:05Z minchau $
*/
package org.apache.xml.dtm.ref;
import org.apache.xml.dtm.DTM;
import org.apache.xml.dtm.DTMAxisIterator;
import org.apache.xml.utils.IntVector;
import org.w3c.dom.Node;
/**
* DTMAxisNodeList
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:
*
State: In progress!!
* */ public class DTMAxisIterNodeList extends DTMNodeListBase { private DTM m_dtm; private DTMAxisIterator m_iter; private IntVector m_cachedNodes; private int m_last = -1; //================================================================ // Methods unique to this class private DTMAxisIterNodeList() { } /** * Public constructor: Wrap a DTMNodeList around an existing * and preconfigured DTMAxisIterator */ public DTMAxisIterNodeList(DTM dtm, DTMAxisIterator dtmAxisIterator) { if (dtmAxisIterator == null) { m_last = 0; } else { m_cachedNodes = new IntVector(); m_dtm = dtm; } m_iter = dtmAxisIterator; } /** * Access the wrapped DTMIterator. I'm not sure whether anyone will * need this or not, but let's write it and think about it. * */ public DTMAxisIterator getDTMAxisIterator() { return m_iter; } //================================================================ // org.w3c.dom.NodeList API follows /** * Returns theindex
th 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 index
th position in the
* NodeList
, or null
if that is not a valid
* index.
*/
public Node item(int index) {
if (m_iter != null) {
int node;
int count = m_cachedNodes.size();
if (count > index) {
node = m_cachedNodes.elementAt(index);
return m_dtm.getNode(node);
} else if (m_last == -1) {
while (((node = m_iter.next()) != DTMAxisIterator.END)
&& count <= index) {
m_cachedNodes.addElement(node);
count++;
}
if (node == DTMAxisIterator.END) {
m_last = count;
} else {
return m_dtm.getNode(node);
}
}
}
return null;
}
/**
* The number of nodes in the list. The range of valid child node indices
* is 0 to length-1
inclusive.
*/
public int getLength() {
if (m_last == -1) {
int node;
while ((node = m_iter.next()) != DTMAxisIterator.END) {
m_cachedNodes.addElement(node);
}
m_last = m_cachedNodes.size();
}
return m_last;
}
}