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1 package com.thaiopensource.util;
2
3 import java.util.Hashtable  ;
4 import java.util.Enumeration ;
5
6 public class PropertyMapBuilder {
7 private Hashtable map;
8 private PropertyId[] keys;
9
10 private static class PropertyMapImpl implements PropertyMap {
11 private final Hashtable map;
12 private final PropertyId[] keys;
13
14 private PropertyMapImpl(Hashtable map, PropertyId[] keys) {
15 this.map = map;
16 this.keys = keys;
17 }
18
19 public Object get(PropertyId pid) {
20 return map.get(pid);
21 }
22
23 public int size() {
24 return keys.length;
25 }
26
27 public boolean contains(PropertyId pid) {
28 return map.get(pid) != null;
29 }
30
31 public PropertyId getKey(int i) {
32 return keys[i];
33 }
34 }
35
36 public PropertyMapBuilder() {
37 this.map = new Hashtable ();
38 }
39
40 public PropertyMapBuilder(PropertyMap pm) {
41 if (pm instanceof PropertyMapImpl) {
42 PropertyMapImpl pmi = (PropertyMapImpl)pm;
43 this.map = pmi.map;
44 this.keys = pmi.keys;
45 }
46 else {
47 this.map = new Hashtable ();
48 for (int i = 0, len = pm.size(); i < len; i++) {
49 PropertyId pid = pm.getKey(i);
50 put(pid, pm.get(pid));
51 }
52 }
53 }
54
55 private void lock() {
56 if (keys != null)
57 return;
58 keys = new PropertyId[map.size()];
59 int i = 0;
60 for (Enumeration e = map.keys(); e.hasMoreElements();)
61 keys[i++] = (PropertyId)e.nextElement();
62 }
63
64 private void copyIfLocked() {
65 if (keys == null)
66 return;
67 Hashtable newMap = new Hashtable ();
68 for (int i = 0; i < keys.length; i++)
69 newMap.put(keys[i], map.get(keys[i]));
70 map = newMap;
71 keys = null;
72 }
73
74 public PropertyMap toPropertyMap() {
75 lock();
76 return new PropertyMapImpl(map, keys);
77 }
78
79 public Object put(PropertyId id, Object value) {
80 copyIfLocked();
81 if (value == null)
82 return map.remove(id);
83 if (!id.getValueClass().isInstance(value))
84 throw new ClassCastException ();
85 return map.put(id, value);
86 }
87
88 public Object get(PropertyId pid) {
89 return map.get(pid);
90 }
91
92 public boolean contains(PropertyId pid) {
93 return map.get(pid) != null;
94 }
95 }
96 |
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