/*
* 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.commons.jxpath.ri.model.jdom;
import java.util.Collections;
import java.util.List;
import org.apache.commons.jxpath.ri.compiler.NodeTest;
import org.apache.commons.jxpath.ri.model.NodeIterator;
import org.apache.commons.jxpath.ri.model.NodePointer;
import org.jdom.Document;
import org.jdom.Element;
/**
* An iterator of children of a JDOM Node.
*
* @author Dmitri Plotnikov
* @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
*/
public class JDOMNodeIterator implements NodeIterator {
private NodePointer parent;
private NodeTest nodeTest;
private boolean reverse;
private int position = 0;
private int index = 0;
private List children;
private Object child;
/**
* Create a new JDOMNodeIterator.
* @param parent pointer
* @param nodeTest test
* @param reverse whether to iterate in reverse
* @param startWith starting pointer
*/
public JDOMNodeIterator(
NodePointer parent, NodeTest nodeTest,
boolean reverse, NodePointer startWith) {
this.parent = parent;
if (startWith != null) {
this.child = startWith.getNode();
}
// TBD: optimize me for different node tests
Object node = parent.getNode();
if (node instanceof Document) {
this.children = ((Document) node).getContent();
}
else if (node instanceof Element) {
this.children = ((Element) node).getContent();
}
else {
this.children = Collections.EMPTY_LIST;
}
this.nodeTest = nodeTest;
this.reverse = reverse;
}
public NodePointer getNodePointer() {
if (child == null) {
if (!setPosition(1)) {
return null;
}
position = 0;
}
return new JDOMNodePointer(parent, child);
}
public int getPosition() {
return position;
}
public boolean setPosition(int position) {
while (this.position < position) {
if (!next()) {
return false;
}
}
while (this.position > position) {
if (!previous()) {
return false;
}
}
return true;
}
/**
* This is actually never invoked during the normal evaluation
* of xpaths - an iterator is always going forward, never backwards.
* So, this is implemented only for completeness and perhaps for
* those who use these iterators outside of XPath evaluation.
* @return boolean
*/
private boolean previous() {
position--;
if (!reverse) {
while (--index >= 0) {
child = children.get(index);
if (testChild()) {
return true;
}
}
}
else {
for (; index < children.size(); index++) {
child = children.get(index);
if (testChild()) {
return true;
}
}
}
return false;
}
/**
* Iterate to next pointer.
* @return whether valid
*/
private boolean next() {
position++;
if (!reverse) {
if (position == 1) {
index = 0;
if (child != null) {
index = children.indexOf(child) + 1;
}
}
else {
index++;
}
for (; index < children.size(); index++) {
child = children.get(index);
if (testChild()) {
return true;
}
}
return false;
}
else {
if (position == 1) {
index = children.size() - 1;
if (child != null) {
index = children.indexOf(child) - 1;
}
}
else {
index--;
}
for (; index >= 0; index--) {
child = children.get(index);
if (testChild()) {
return true;
}
}
return false;
}
}
/**
* Test a child node.
* @return whether test passes.
*/
private boolean testChild() {
return JDOMNodePointer.testNode(parent, child, nodeTest);
}
}
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