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Java > Open Source Codes > org > apache > commons > jxpath > ri > model > dom > DOMNodeIterator


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.jxpath.ri.model.dom;
17
18 import org.apache.commons.jxpath.ri.compiler.NodeTest;
19 import org.apache.commons.jxpath.ri.model.NodeIterator;
20 import org.apache.commons.jxpath.ri.model.NodePointer;
21 import org.w3c.dom.Node JavaDoc;
22
23 /**
24  * An iterator of children of a DOM Node.
25  *
26  * @author Dmitri Plotnikov
27  * @version $Revision: 1.11 $ $Date: 2004/04/01 02:55:32 $
28  */
29 public class DOMNodeIterator implements NodeIterator {
30     private NodePointer parent;
31     private NodeTest nodeTest;
32     private Node JavaDoc node;
33     private Node JavaDoc child = null;
34     private boolean reverse;
35     private int position = 0;
36
37     public DOMNodeIterator(
38         NodePointer parent,
39         NodeTest nodeTest,
40         boolean reverse,
41         NodePointer startWith)
42     {
43         this.parent = parent;
44         this.node = (Node JavaDoc) parent.getNode();
45         if (startWith != null) {
46             this.child = (Node JavaDoc) startWith.getNode();
47         }
48         this.nodeTest = nodeTest;
49         this.reverse = reverse;
50     }
51
52     public NodePointer getNodePointer() {
53         if (position == 0) {
54             setPosition(1);
55         }
56         if (child == null) {
57             return null;
58         }
59         return new DOMNodePointer(parent, child);
60     }
61
62     public int getPosition() {
63         return position;
64     }
65
66     public boolean setPosition(int position) {
67         while (this.position < position) {
68             if (!next()) {
69                 return false;
70             }
71         }
72         while (this.position > position) {
73             if (!previous()) {
74                 return false;
75             }
76         }
77         return true;
78     }
79
80     private boolean previous() {
81         position--;
82         if (!reverse) {
83             if (position == 0) {
84                 child = null;
85             }
86             else if (child == null) {
87                 child = node.getLastChild();
88             }
89             else {
90                 child = child.getPreviousSibling();
91             }
92             while (child != null && !testChild()) {
93                 child = child.getPreviousSibling();
94             }
95         }
96         else {
97             child = child.getNextSibling();
98             while (child != null && !testChild()) {
99                 child = child.getNextSibling();
100             }
101         }
102         return child != null;
103     }
104
105     private boolean next() {
106         position++;
107         if (!reverse) {
108             if (position == 1) {
109                 if (child == null) {
110                     child = node.getFirstChild();
111                 }
112                 else {
113                     child = child.getNextSibling();
114                 }
115             }
116             else {
117                 child = child.getNextSibling();
118             }
119             while (child != null && !testChild()) {
120                 child = child.getNextSibling();
121             }
122         }
123         else {
124             if (position == 1) {
125                 if (child == null) {
126                     child = node.getLastChild();
127                 }
128                 else {
129                     child = child.getPreviousSibling();
130                 }
131             }
132             else {
133                 child = child.getPreviousSibling();
134             }
135             while (child != null && !testChild()) {
136                 child = child.getPreviousSibling();
137             }
138         }
139         return child != null;
140     }
141
142     private boolean testChild() {
143         return DOMNodePointer.testNode(child, nodeTest);
144     }
145 }
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