Mercurial > hg > blitz_condensed
comparison src/com/go/trove/util/NullKeyMap.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
---|---|
date | Sat, 21 Mar 2009 11:00:06 +0000 |
parents | |
children |
comparison
equal
deleted
inserted
replaced
-1:000000000000 | 0:3dc0c5604566 |
---|---|
1 /* ==================================================================== | |
2 * Trove - Copyright (c) 1997-2000 Walt Disney Internet Group | |
3 * ==================================================================== | |
4 * The Tea Software License, Version 1.1 | |
5 * | |
6 * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved. | |
7 * | |
8 * Redistribution and use in source and binary forms, with or without | |
9 * modification, are permitted provided that the following conditions | |
10 * are met: | |
11 * | |
12 * 1. Redistributions of source code must retain the above copyright | |
13 * notice, this list of conditions and the following disclaimer. | |
14 * | |
15 * 2. Redistributions in binary form must reproduce the above copyright | |
16 * notice, this list of conditions and the following disclaimer in | |
17 * the documentation and/or other materials provided with the | |
18 * distribution. | |
19 * | |
20 * 3. The end-user documentation included with the redistribution, | |
21 * if any, must include the following acknowledgment: | |
22 * "This product includes software developed by the | |
23 * Walt Disney Internet Group (http://opensource.go.com/)." | |
24 * Alternately, this acknowledgment may appear in the software itself, | |
25 * if and wherever such third-party acknowledgments normally appear. | |
26 * | |
27 * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must | |
28 * not be used to endorse or promote products derived from this | |
29 * software without prior written permission. For written | |
30 * permission, please contact opensource@dig.com. | |
31 * | |
32 * 5. Products derived from this software may not be called "Tea", | |
33 * "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet", | |
34 * "Kettle", "Trove" or "BeanDoc" appear in their name, without prior | |
35 * written permission of the Walt Disney Internet Group. | |
36 * | |
37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED | |
38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
40 * DISCLAIMED. IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS | |
41 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
42 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
43 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
44 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY | |
45 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
46 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
47 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
48 * ==================================================================== | |
49 * | |
50 * For more information about Tea, please see http://opensource.go.com/. | |
51 */ | |
52 | |
53 package com.go.trove.util; | |
54 | |
55 import java.util.*; | |
56 import java.io.Serializable; | |
57 | |
58 /****************************************************************************** | |
59 * A Map supporting null keys that wraps a Map that doesn't support null keys. | |
60 * NullKeyMap substitutes null keys with a special placeholder object. This | |
61 * technique does not work when the wrapped Map is a TreeMap because it cannot | |
62 * be compared against other objects. In order for TreeMaps to support null | |
63 * keys, use any of the null ordering comparators found in the {@link Utils} | |
64 * class. | |
65 * | |
66 * @author Brian S O'Neill | |
67 * @version | |
68 * <!--$$Revision: 1.1 $-->, <!--$$JustDate:--> 9/07/00 <!-- $--> | |
69 */ | |
70 public class NullKeyMap extends AbstractMap implements Serializable { | |
71 // Instead of using null as a key, use this placeholder. | |
72 private static final Object NULL = new Serializable() {}; | |
73 | |
74 private Map mMap; | |
75 | |
76 private transient Set mKeySet; | |
77 private transient Set mEntrySet; | |
78 | |
79 /** | |
80 * @param map The map to wrap. | |
81 */ | |
82 public NullKeyMap(Map map) { | |
83 mMap = map; | |
84 } | |
85 | |
86 public int size() { | |
87 return mMap.size(); | |
88 } | |
89 | |
90 public boolean isEmpty() { | |
91 return mMap.isEmpty(); | |
92 } | |
93 | |
94 public boolean containsKey(Object key) { | |
95 return (key == null) ? mMap.containsKey(NULL) : mMap.containsKey(key); | |
96 } | |
97 | |
98 public boolean containsValue(Object value) { | |
99 return mMap.containsValue(value); | |
100 } | |
101 | |
102 public Object get(Object key) { | |
103 return (key == null) ? mMap.get(NULL) : mMap.get(key); | |
104 } | |
105 | |
106 public Object put(Object key, Object value) { | |
107 return mMap.put((key == null) ? NULL : key, value); | |
108 } | |
109 | |
110 public Object remove(Object key) { | |
111 return (key == null) ? mMap.remove(NULL) : mMap.remove(key); | |
112 } | |
113 | |
114 public void putAll(Map map) { | |
115 Iterator it = map.entrySet().iterator(); | |
116 while (it.hasNext()) { | |
117 Map.Entry entry = (Map.Entry)it.next(); | |
118 put(entry.getKey(), entry.getValue()); | |
119 } | |
120 } | |
121 | |
122 public void clear() { | |
123 mMap.clear(); | |
124 } | |
125 | |
126 public Set keySet() { | |
127 if (mKeySet == null) { | |
128 mKeySet = new AbstractSet() { | |
129 public Iterator iterator() { | |
130 final Iterator it = mMap.keySet().iterator(); | |
131 | |
132 return new Iterator() { | |
133 public boolean hasNext() { | |
134 return it.hasNext(); | |
135 } | |
136 | |
137 public Object next() { | |
138 Object key = it.next(); | |
139 return (key == NULL) ? null : key; | |
140 } | |
141 | |
142 public void remove() { | |
143 it.remove(); | |
144 } | |
145 }; | |
146 } | |
147 | |
148 public boolean contains(Object key) { | |
149 return containsKey((key == null) ? NULL : key); | |
150 } | |
151 | |
152 public boolean remove(Object key) { | |
153 if (key == null) { | |
154 key = NULL; | |
155 } | |
156 if (containsKey(key)) { | |
157 NullKeyMap.this.remove(key); | |
158 return true; | |
159 } | |
160 else { | |
161 return false; | |
162 } | |
163 } | |
164 | |
165 public int size() { | |
166 return NullKeyMap.this.size(); | |
167 } | |
168 | |
169 public void clear() { | |
170 NullKeyMap.this.clear(); | |
171 } | |
172 }; | |
173 } | |
174 | |
175 return mKeySet; | |
176 } | |
177 | |
178 public Collection values() { | |
179 return mMap.values(); | |
180 } | |
181 | |
182 public Set entrySet() { | |
183 if (mEntrySet == null) { | |
184 mEntrySet = new AbstractSet() { | |
185 public Iterator iterator() { | |
186 final Iterator it = mMap.entrySet().iterator(); | |
187 | |
188 return new Iterator() { | |
189 public boolean hasNext() { | |
190 return it.hasNext(); | |
191 } | |
192 | |
193 public Object next() { | |
194 final Map.Entry entry = (Map.Entry)it.next(); | |
195 if (entry.getKey() == NULL) { | |
196 return new AbstractMapEntry() { | |
197 public Object getKey() { | |
198 return null; | |
199 } | |
200 | |
201 public Object getValue() { | |
202 return entry.getValue(); | |
203 } | |
204 | |
205 public Object setValue(Object value) { | |
206 return entry.setValue(value); | |
207 } | |
208 }; | |
209 } | |
210 else { | |
211 return entry; | |
212 } | |
213 } | |
214 | |
215 public void remove() { | |
216 it.remove(); | |
217 } | |
218 }; | |
219 } | |
220 | |
221 public boolean contains(Object obj) { | |
222 if (!(obj instanceof Map.Entry)) { | |
223 return false; | |
224 } | |
225 Map.Entry entry = (Map.Entry)obj; | |
226 Object key = entry.getKey(); | |
227 Object value = entry.getValue(); | |
228 if (key == null) { | |
229 key = NULL; | |
230 } | |
231 Object lookup = get(key); | |
232 if (lookup == null) { | |
233 return value == null; | |
234 } | |
235 else { | |
236 return lookup.equals(value); | |
237 } | |
238 } | |
239 | |
240 public boolean remove(Object obj) { | |
241 if (!(obj instanceof Map.Entry)) { | |
242 return false; | |
243 } | |
244 Map.Entry entry = ((Map.Entry)obj); | |
245 Object key = entry.getKey(); | |
246 if (key == null) { | |
247 key = NULL; | |
248 } | |
249 if (containsKey(key)) { | |
250 NullKeyMap.this.remove(key); | |
251 return true; | |
252 } | |
253 else { | |
254 return false; | |
255 } | |
256 } | |
257 | |
258 public int size() { | |
259 return NullKeyMap.this.size(); | |
260 } | |
261 | |
262 public void clear() { | |
263 NullKeyMap.this.clear(); | |
264 } | |
265 }; | |
266 } | |
267 | |
268 return mEntrySet; | |
269 } | |
270 } |