001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jxpath.ri.model.dom;
018
019 import org.apache.commons.jxpath.ri.compiler.NodeTest;
020 import org.apache.commons.jxpath.ri.model.NodeIterator;
021 import org.apache.commons.jxpath.ri.model.NodePointer;
022 import org.w3c.dom.Node;
023
024 /**
025 * An iterator of children of a DOM Node.
026 *
027 * @author Dmitri Plotnikov
028 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
029 */
030 public class DOMNodeIterator implements NodeIterator {
031 private NodePointer parent;
032 private NodeTest nodeTest;
033 private Node node;
034 private Node child = null;
035 private boolean reverse;
036 private int position = 0;
037
038 /**
039 * Create a new DOMNodeIterator.
040 * @param parent parent pointer
041 * @param nodeTest test
042 * @param reverse whether to iterate in reverse
043 * @param startWith starting pointer
044 */
045 public DOMNodeIterator(
046 NodePointer parent,
047 NodeTest nodeTest,
048 boolean reverse,
049 NodePointer startWith) {
050 this.parent = parent;
051 this.node = (Node) parent.getNode();
052 if (startWith != null) {
053 this.child = (Node) startWith.getNode();
054 }
055 this.nodeTest = nodeTest;
056 this.reverse = reverse;
057 }
058
059 public NodePointer getNodePointer() {
060 if (position == 0) {
061 setPosition(1);
062 }
063 return child == null ? null : new DOMNodePointer(parent, child);
064 }
065
066 public int getPosition() {
067 return position;
068 }
069
070 public boolean setPosition(int position) {
071 while (this.position < position) {
072 if (!next()) {
073 return false;
074 }
075 }
076 while (this.position > position) {
077 if (!previous()) {
078 return false;
079 }
080 }
081 return true;
082 }
083
084 /**
085 * Set the previous position.
086 * @return whether valid
087 */
088 private boolean previous() {
089 position--;
090 if (!reverse) {
091 if (position == 0) {
092 child = null;
093 }
094 else if (child == null) {
095 child = node.getLastChild();
096 }
097 else {
098 child = child.getPreviousSibling();
099 }
100 while (child != null && !testChild()) {
101 child = child.getPreviousSibling();
102 }
103 }
104 else {
105 child = child.getNextSibling();
106 while (child != null && !testChild()) {
107 child = child.getNextSibling();
108 }
109 }
110 return child != null;
111 }
112
113 /**
114 * Set the next position.
115 * @return whether valid
116 */
117 private boolean next() {
118 position++;
119 if (!reverse) {
120 if (position == 1) {
121 if (child == null) {
122 child = node.getFirstChild();
123 }
124 else {
125 child = child.getNextSibling();
126 }
127 }
128 else {
129 child = child.getNextSibling();
130 }
131 while (child != null && !testChild()) {
132 child = child.getNextSibling();
133 }
134 }
135 else {
136 if (position == 1) {
137 if (child == null) {
138 child = node.getLastChild();
139 }
140 else {
141 child = child.getPreviousSibling();
142 }
143 }
144 else {
145 child = child.getPreviousSibling();
146 }
147 while (child != null && !testChild()) {
148 child = child.getPreviousSibling();
149 }
150 }
151 return child != null;
152 }
153
154 /**
155 * Test child.
156 * @return result of the test
157 */
158 private boolean testChild() {
159 return DOMNodePointer.testNode(child, nodeTest);
160 }
161 }