001: /*
002: License $Id: FastReadSyncMap.java,v 1.6 2005/03/15 20:09:44 hendriks73 Exp $
003:
004: Copyright (c) 2001-2005 tagtraum industries.
005:
006: LGPL
007: ====
008:
009: jo! is free software; you can redistribute it and/or
010: modify it under the terms of the GNU Lesser General Public
011: License as published by the Free Software Foundation; either
012: version 2.1 of the License, or (at your option) any later version.
013:
014: jo! is distributed in the hope that it will be useful,
015: but WITHOUT ANY WARRANTY; without even the implied warranty of
016: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017: Lesser General Public License for more details.
018:
019: You should have received a copy of the GNU Lesser General Public
020: License along with this library; if not, write to the Free Software
021: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
022:
023: For LGPL see <http://www.fsf.org/copyleft/lesser.txt>
024:
025:
026: Sun license
027: ===========
028:
029: This release contains software by Sun Microsystems. Therefore
030: the following conditions have to be met, too. They apply to the
031: files
032:
033: - lib/mail.jar
034: - lib/activation.jar
035: - lib/jsse.jar
036: - lib/jcert.jar
037: - lib/jaxp.jar
038: - lib/crimson.jar
039: - lib/servlet.jar
040: - lib/jnet.jar
041: - lib/jaas.jar
042: - lib/jaasmod.jar
043:
044: contained in this release.
045:
046: a. Licensee may not modify the Java Platform
047: Interface (JPI, identified as classes contained within the javax
048: package or any subpackages of the javax package), by creating additional
049: classes within the JPI or otherwise causing the addition to or modification
050: of the classes in the JPI. In the event that Licensee creates any
051: Java-related API and distribute such API to others for applet or
052: application development, you must promptly publish broadly, an accurate
053: specification for such API for free use by all developers of Java-based
054: software.
055:
056: b. Software is confidential copyrighted information of Sun and
057: title to all copies is retained by Sun and/or its licensors. Licensee
058: shall not modify, decompile, disassemble, decrypt, extract, or otherwise
059: reverse engineer Software. Software may not be leased, assigned, or
060: sublicensed, in whole or in part. Software is not designed or intended
061: for use in on-line control of aircraft, air traffic, aircraft navigation
062: or aircraft communications; or in the design, construction, operation or
063: maintenance of any nuclear facility. Licensee warrants that it will not
064: use or redistribute the Software for such purposes.
065:
066: c. Software is provided "AS IS," without a warranty
067: of any kind. ALL EXPRESS OR IMPLIED REPRESENTATIONS AND WARRANTIES,
068: INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
069: PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED.
070:
071: d. This License is effective until terminated. Licensee may
072: terminate this License at any time by destroying all copies of Software.
073: This License will terminate immediately without notice from Sun if Licensee
074: fails to comply with any provision of this License. Upon such termination,
075: Licensee must destroy all copies of Software.
076:
077: e. Software, including technical data, is subject to U.S.
078: export control laws, including the U.S. Export Administration Act and its
079: associated regulations, and may be subject to export or import regulations
080: in other countries. Licensee agrees to comply strictly with all such
081: regulations and acknowledges that it has the responsibility to obtain
082: licenses to export, re-export, or import Software. Software may not be
083: downloaded, or otherwise exported or re-exported (i) into, or to a national
084: or resident of, Cuba, Iraq, Iran, North Korea, Libya, Sudan, Syria or any
085: country to which the U.S. has embargoed goods; or (ii) to anyone on the
086: U.S. Treasury Department's list of Specially Designated Nations or the U.S.
087: Commerce Department's Table of Denial Orders.
088:
089:
090: Feedback
091: ========
092:
093: We encourage your feedback and suggestions and want to use your feedback to
094: improve the Software. Send all such feedback to:
095: <feedback@tagtraum.com>
096:
097: For more information on tagtraum industries and jo!
098: please see <http://www.tagtraum.com/>.
099:
100:
101: */
102: package com.tagtraum.perf.util;
103:
104: import java.lang.reflect.Method;
105: import java.util.Collection;
106: import java.util.Map;
107: import java.util.ResourceBundle;
108: import java.util.Set;
109:
110: /**
111: * This map is suits, your needs if you need to read most of the time
112: * and only have to write seldomly. Read access therefore is very fast,
113: * while write access is slow and gets slower in a linear fashion
114: * with the number of entries in the map. Also memory consumption
115: * increases during write operations linear to the number of entries.
116: * <p>
117: * Provides synchronization for put, putAll, remove and clear.
118: * All other methods are unsynchronized. Because the above mentioned operations
119: * are done on a copy, this is still threadsafe.
120: * <p>
121: * <b>Do not</b> use this map, if you need to modify it often.
122: *
123: * @author Hendrik Schreiber
124: * @version 1.1beta1 $Id: FastReadSyncMap.java,v 1.6 2005/03/15 20:09:44 hendriks73 Exp $
125: */
126: public class FastReadSyncMap implements Map {
127:
128: /**
129: * Source-Version
130: */
131: public static String vcid = "$Id: FastReadSyncMap.java,v 1.6 2005/03/15 20:09:44 hendriks73 Exp $";
132:
133: private static ResourceBundle localStrings = ResourceBundle
134: .getBundle("com.tagtraum.perf.util.localStrings");
135:
136: private volatile Map map;
137: private Method cloneMethod;
138:
139: public FastReadSyncMap(Map map) throws CloneNotSupportedException {
140: this .map = map;
141: if (!(map instanceof Cloneable))
142: throw new CloneNotSupportedException(localStrings
143: .getString("map_is_not_cloneable"));
144: try {
145: cloneMethod = map.getClass().getMethod("clone",
146: new Class[0]);
147: } catch (Exception e) {
148: throw new CloneNotSupportedException(localStrings
149: .getString("map_is_not_cloneable")
150: + " " + e.toString());
151: }
152: }
153:
154: public int size() {
155: return map.size();
156: }
157:
158: public boolean isEmpty() {
159: return map.isEmpty();
160: }
161:
162: public boolean containsKey(Object key) {
163: return map.containsKey(key);
164: }
165:
166: public boolean containsValue(Object value) {
167: return map.containsValue(value);
168: }
169:
170: public Object get(Object key) {
171: return map.get(key);
172: }
173:
174: // Modification Operations
175:
176: public synchronized Object put(Object key, Object value) {
177: Map clone = cloneMap();
178: Object result = clone.put(key, value);
179: map = clone;
180: return result;
181: }
182:
183: public synchronized Object remove(Object key) {
184: Map clone = cloneMap();
185: Object result = clone.remove(key);
186: map = clone;
187: return result;
188: }
189:
190: // Bulk Operations
191:
192: public synchronized void putAll(Map t) {
193: Map clone = cloneMap();
194: clone.putAll(t);
195: map = clone;
196: }
197:
198: public synchronized void clear() {
199: Map clone = cloneMap();
200: clone.clear();
201: map = clone;
202: }
203:
204: // Views
205:
206: /**
207: * Returns the keyset of the internal map. This is NOT a copy!
208: * Manipulating actions are not synchronized.
209: */
210: public Set keySet() {
211: return map.keySet();
212: }
213:
214: /**
215: * Returns the values of the internal map. This is NOT a copy!
216: * Manipulating actions are not synchronized.
217: */
218: public Collection values() {
219: return map.values();
220: }
221:
222: /**
223: * Returns an entry set of the internal map. This is NOT a copy!
224: * Manipulating actions are not synchronized.
225: */
226: public Set entrySet() {
227: return map.entrySet();
228: }
229:
230: // Comparison and hashing
231:
232: public boolean equals(Object o) {
233: return map.equals(o);
234: }
235:
236: public int hashCode() {
237: return map.hashCode();
238: }
239:
240: private Map cloneMap() {
241: try {
242: return (Map) cloneMethod.invoke(map,
243: (java.lang.Object[]) null);
244: } catch (Exception e) {
245: // should not be possible
246: e.printStackTrace();
247: throw new RuntimeException(e.toString());
248: }
249: }
250:
251: }
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