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Java > Open Source Codes > org > apache > commons > jxpath > BasicNodeSet


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;
17
18 import java.util.ArrayList JavaDoc;
19 import java.util.Collections JavaDoc;
20 import java.util.List JavaDoc;
21
22 /**
23  * A simple implementation of NodeSet that behaves as a collection of pointers.
24  * @author Dmitri Plotnikov
25  * @version $Revision: 1.3 $ $Date: 2004/02/29 14:17:42 $
26  */
27 public class BasicNodeSet implements NodeSet {
28     private List JavaDoc pointers = new ArrayList JavaDoc();
29     private List JavaDoc readOnlyPointers;
30     private List JavaDoc nodes;
31     private List JavaDoc values;
32
33     public void add(Pointer pointer) {
34         pointers.add(pointer);
35         readOnlyPointers = null;
36     }
37     
38     public void remove(Pointer pointer) {
39         pointers.remove(pointer);
40         readOnlyPointers = null;
41     }
42     
43     public List JavaDoc getPointers() {
44         if (readOnlyPointers == null) {
45             readOnlyPointers = Collections.unmodifiableList(pointers);
46         }
47         return readOnlyPointers;
48     }
49
50     public List JavaDoc getNodes() {
51         if (nodes == null) {
52             nodes = new ArrayList JavaDoc();
53             for (int i = 0; i < pointers.size(); i++) {
54                 Pointer pointer = (Pointer) pointers.get(i);
55                 nodes.add(pointer.getValue());
56             }
57             nodes = Collections.unmodifiableList(nodes);
58         }
59         return nodes;
60     }
61
62     public List JavaDoc getValues() {
63         if (values == null) {
64             values = new ArrayList JavaDoc();
65             for (int i = 0; i < pointers.size(); i++) {
66                 Pointer pointer = (Pointer) pointers.get(i);
67                 values.add(pointer.getValue());
68             }
69             values = Collections.unmodifiableList(values);
70         }
71         return values;
72     }
73     
74     public String JavaDoc toString() {
75         return pointers.toString();
76     }
77 }
78
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