01: /*
02: * Copyright 1999-2004 The Apache Software Foundation
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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;
19: import java.util.Collections;
20: import java.util.List;
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 pointers = new ArrayList();
29: private List readOnlyPointers;
30: private List nodes;
31: private List 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 getPointers() {
44: if (readOnlyPointers == null) {
45: readOnlyPointers = Collections.unmodifiableList(pointers);
46: }
47: return readOnlyPointers;
48: }
49:
50: public List getNodes() {
51: if (nodes == null) {
52: nodes = new ArrayList();
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 getValues() {
63: if (values == null) {
64: values = new ArrayList();
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 toString() {
75: return pointers.toString();
76: }
77: }
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