1 /* 2 * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * This file is available under and governed by the GNU General Public 28 * License version 2 only, as published by the Free Software Foundation. 29 * However, the following notice accompanied the original version of this 30 * file: 31 * 32 * Copyright (c) 2009-2012, Stephen Colebourne & Michael Nascimento Santos 33 * 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions are met: 38 * 39 * * Redistributions of source code must retain the above copyright notice, 40 * this list of conditions and the following disclaimer. 41 * 42 * * Redistributions in binary form must reproduce the above copyright notice, 43 * this list of conditions and the following disclaimer in the documentation 44 * and/or other materials provided with the distribution. 45 * 46 * * Neither the name of JSR-310 nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 51 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 52 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 53 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 54 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 55 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 56 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 57 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 59 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 60 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 package java.time.zone; 63 64 import java.security.AccessController; 65 import java.security.PrivilegedAction; 66 import java.time.ZoneId; 67 import java.time.ZonedDateTime; 68 import java.util.ArrayList; 69 import java.util.HashSet; 70 import java.util.Iterator; 71 import java.util.List; 72 import java.util.NavigableMap; 73 import java.util.Objects; 74 import java.util.ServiceConfigurationError; 75 import java.util.ServiceLoader; 76 import java.util.Set; 77 import java.util.concurrent.ConcurrentHashMap; 78 import java.util.concurrent.ConcurrentMap; 79 import java.util.concurrent.CopyOnWriteArrayList; 80 import java.util.Collections; 81 82 /** 83 * Provider of time-zone rules to the system. 84 * <p> 85 * This class manages the configuration of time-zone rules. 86 * The static methods provide the public API that can be used to manage the providers. 87 * The abstract methods provide the SPI that allows rules to be provided. 88 * <p> 89 * ZoneRulesProvider may be installed in an instance of the Java Platform as 90 * extension classes, that is, jar files placed into any of the usual extension 91 * directories. Installed providers are loaded using the service-provider loading 92 * facility defined by the {@link ServiceLoader} class. A ZoneRulesProvider 93 * identifies itself with a provider configuration file named 94 * {@code java.time.zone.ZoneRulesProvider} in the resource directory 95 * {@code META-INF/services}. The file should contain a line that specifies the 96 * fully qualified concrete zonerules-provider class name. 97 * Providers may also be made available by adding them to the class path or by 98 * registering themselves via {@link #registerProvider} method. 99 * <p> 100 * The Java virtual machine has a default provider that provides zone rules 101 * for the time-zones defined by IANA Time Zone Database (TZDB). If the system 102 * property {@code java.time.zone.DefaultZoneRulesProvider} is defined then 103 * it is taken to be the fully-qualified name of a concrete ZoneRulesProvider 104 * class to be loaded as the default provider, using the system class loader. 105 * If this system property is not defined, a system-default provider will be 106 * loaded to serve as the default provider. 107 * <p> 108 * Rules are looked up primarily by zone ID, as used by {@link ZoneId}. 109 * Only zone region IDs may be used, zone offset IDs are not used here. 110 * <p> 111 * Time-zone rules are political, thus the data can change at any time. 112 * Each provider will provide the latest rules for each zone ID, but they 113 * may also provide the history of how the rules changed. 114 * 115 * @implSpec 116 * This interface is a service provider that can be called by multiple threads. 117 * Implementations must be immutable and thread-safe. 118 * <p> 119 * Providers must ensure that once a rule has been seen by the application, the 120 * rule must continue to be available. 121 * <p> 122 * Providers are encouraged to implement a meaningful {@code toString} method. 123 * <p> 124 * Many systems would like to update time-zone rules dynamically without stopping the JVM. 125 * When examined in detail, this is a complex problem. 126 * Providers may choose to handle dynamic updates, however the default provider does not. 127 * 128 * @since 1.8 129 */ 130 public abstract class ZoneRulesProvider { 131 132 /** 133 * The set of loaded providers. 134 */ 135 private static final CopyOnWriteArrayList<ZoneRulesProvider> PROVIDERS = new CopyOnWriteArrayList<>(); 136 /** 137 * The lookup from zone ID to provider. 138 */ 139 private static final ConcurrentMap<String, ZoneRulesProvider> ZONES = new ConcurrentHashMap<>(512, 0.75f, 2); 140 141 /** 142 * The zone ID data 143 */ 144 private static volatile Set<String> ZONE_IDS; 145 146 static { 147 // BEGIN Android-changed: use a single hard-coded provider. 148 /* 149 // if the property java.time.zone.DefaultZoneRulesProvider is 150 // set then its value is the class name of the default provider 151 final List<ZoneRulesProvider> loaded = new ArrayList<>(); 152 AccessController.doPrivileged(new PrivilegedAction<>() { 153 public Object run() { 154 String prop = System.getProperty("java.time.zone.DefaultZoneRulesProvider"); 155 if (prop != null) { 156 try { 157 Class<?> c = Class.forName(prop, true, ClassLoader.getSystemClassLoader()); 158 @SuppressWarnings("deprecation") 159 ZoneRulesProvider provider = ZoneRulesProvider.class.cast(c.newInstance()); 160 registerProvider(provider); 161 loaded.add(provider); 162 } catch (Exception x) { 163 throw new Error(x); 164 } 165 } else { 166 registerProvider(new TzdbZoneRulesProvider()); 167 } 168 return null; 169 } 170 }); 171 172 ServiceLoader<ZoneRulesProvider> sl = ServiceLoader.load(ZoneRulesProvider.class, ClassLoader.getSystemClassLoader()); 173 Iterator<ZoneRulesProvider> it = sl.iterator(); 174 while (it.hasNext()) { 175 ZoneRulesProvider provider; 176 try { 177 provider = it.next(); 178 } catch (ServiceConfigurationError ex) { 179 if (ex.getCause() instanceof SecurityException) { 180 continue; // ignore the security exception, try the next provider 181 } 182 throw ex; 183 } 184 boolean found = false; 185 for (ZoneRulesProvider p : loaded) { 186 if (p.getClass() == provider.getClass()) { 187 found = true; 188 } 189 } 190 if (!found) { 191 registerProvider0(provider); 192 loaded.add(provider); 193 } 194 } 195 // CopyOnWriteList could be slow if lots of providers and each added individually 196 PROVIDERS.addAll(loaded); 197 */ 198 ZoneRulesProvider provider = new IcuZoneRulesProvider(); 199 registerProvider(provider); 200 // END Android-changed: use a single hard-coded provider. 201 } 202 203 //------------------------------------------------------------------------- 204 /** 205 * Gets the set of available zone IDs. 206 * <p> 207 * These IDs are the string form of a {@link ZoneId}. 208 * 209 * @return the unmodifiable set of zone IDs, not null 210 */ getAvailableZoneIds()211 public static Set<String> getAvailableZoneIds() { 212 return ZONE_IDS; 213 } 214 215 /** 216 * Gets the rules for the zone ID. 217 * <p> 218 * This returns the latest available rules for the zone ID. 219 * <p> 220 * This method relies on time-zone data provider files that are configured. 221 * These are loaded using a {@code ServiceLoader}. 222 * <p> 223 * The caching flag is designed to allow provider implementations to 224 * prevent the rules being cached in {@code ZoneId}. 225 * Under normal circumstances, the caching of zone rules is highly desirable 226 * as it will provide greater performance. However, there is a use case where 227 * the caching would not be desirable, see {@link #provideRules}. 228 * 229 * @param zoneId the zone ID as defined by {@code ZoneId}, not null 230 * @param forCaching whether the rules are being queried for caching, 231 * true if the returned rules will be cached by {@code ZoneId}, 232 * false if they will be returned to the user without being cached in {@code ZoneId} 233 * @return the rules, null if {@code forCaching} is true and this 234 * is a dynamic provider that wants to prevent caching in {@code ZoneId}, 235 * otherwise not null 236 * @throws ZoneRulesException if rules cannot be obtained for the zone ID 237 */ getRules(String zoneId, boolean forCaching)238 public static ZoneRules getRules(String zoneId, boolean forCaching) { 239 Objects.requireNonNull(zoneId, "zoneId"); 240 return getProvider(zoneId).provideRules(zoneId, forCaching); 241 } 242 243 /** 244 * Gets the history of rules for the zone ID. 245 * <p> 246 * Time-zones are defined by governments and change frequently. 247 * This method allows applications to find the history of changes to the 248 * rules for a single zone ID. The map is keyed by a string, which is the 249 * version string associated with the rules. 250 * <p> 251 * The exact meaning and format of the version is provider specific. 252 * The version must follow lexicographical order, thus the returned map will 253 * be order from the oldest known rules to the newest available rules. 254 * The default 'TZDB' group uses version numbering consisting of the year 255 * followed by a letter, such as '2009e' or '2012f'. 256 * <p> 257 * Implementations must provide a result for each valid zone ID, however 258 * they do not have to provide a history of rules. 259 * Thus the map will always contain one element, and will only contain more 260 * than one element if historical rule information is available. 261 * 262 * @param zoneId the zone ID as defined by {@code ZoneId}, not null 263 * @return a modifiable copy of the history of the rules for the ID, sorted 264 * from oldest to newest, not null 265 * @throws ZoneRulesException if history cannot be obtained for the zone ID 266 */ getVersions(String zoneId)267 public static NavigableMap<String, ZoneRules> getVersions(String zoneId) { 268 Objects.requireNonNull(zoneId, "zoneId"); 269 return getProvider(zoneId).provideVersions(zoneId); 270 } 271 272 /** 273 * Gets the provider for the zone ID. 274 * 275 * @param zoneId the zone ID as defined by {@code ZoneId}, not null 276 * @return the provider, not null 277 * @throws ZoneRulesException if the zone ID is unknown 278 */ getProvider(String zoneId)279 private static ZoneRulesProvider getProvider(String zoneId) { 280 ZoneRulesProvider provider = ZONES.get(zoneId); 281 if (provider == null) { 282 if (ZONES.isEmpty()) { 283 throw new ZoneRulesException("No time-zone data files registered"); 284 } 285 throw new ZoneRulesException("Unknown time-zone ID: " + zoneId); 286 } 287 return provider; 288 } 289 290 //------------------------------------------------------------------------- 291 /** 292 * Registers a zone rules provider. 293 * <p> 294 * This adds a new provider to those currently available. 295 * A provider supplies rules for one or more zone IDs. 296 * A provider cannot be registered if it supplies a zone ID that has already been 297 * registered. See the notes on time-zone IDs in {@link ZoneId}, especially 298 * the section on using the concept of a "group" to make IDs unique. 299 * <p> 300 * To ensure the integrity of time-zones already created, there is no way 301 * to deregister providers. 302 * 303 * @param provider the provider to register, not null 304 * @throws ZoneRulesException if a zone ID is already registered 305 */ registerProvider(ZoneRulesProvider provider)306 public static void registerProvider(ZoneRulesProvider provider) { 307 Objects.requireNonNull(provider, "provider"); 308 registerProvider0(provider); 309 PROVIDERS.add(provider); 310 } 311 312 /** 313 * Registers the provider. 314 * 315 * @param provider the provider to register, not null 316 * @throws ZoneRulesException if unable to complete the registration 317 */ registerProvider0(ZoneRulesProvider provider)318 private static synchronized void registerProvider0(ZoneRulesProvider provider) { 319 for (String zoneId : provider.provideZoneIds()) { 320 Objects.requireNonNull(zoneId, "zoneId"); 321 ZoneRulesProvider old = ZONES.putIfAbsent(zoneId, provider); 322 if (old != null) { 323 throw new ZoneRulesException( 324 "Unable to register zone as one already registered with that ID: " + zoneId + 325 ", currently loading from provider: " + provider); 326 } 327 } 328 Set<String> combinedSet = new HashSet<String>(ZONES.keySet()); 329 ZONE_IDS = Collections.unmodifiableSet(combinedSet); 330 } 331 332 /** 333 * Refreshes the rules from the underlying data provider. 334 * <p> 335 * This method allows an application to request that the providers check 336 * for any updates to the provided rules. 337 * After calling this method, the offset stored in any {@link ZonedDateTime} 338 * may be invalid for the zone ID. 339 * <p> 340 * Dynamic update of rules is a complex problem and most applications 341 * should not use this method or dynamic rules. 342 * To achieve dynamic rules, a provider implementation will have to be written 343 * as per the specification of this class. 344 * In addition, instances of {@code ZoneRules} must not be cached in the 345 * application as they will become stale. However, the boolean flag on 346 * {@link #provideRules(String, boolean)} allows provider implementations 347 * to control the caching of {@code ZoneId}, potentially ensuring that 348 * all objects in the system see the new rules. 349 * Note that there is likely to be a cost in performance of a dynamic rules 350 * provider. Note also that no dynamic rules provider is in this specification. 351 * 352 * @return true if the rules were updated 353 * @throws ZoneRulesException if an error occurs during the refresh 354 */ refresh()355 public static boolean refresh() { 356 boolean changed = false; 357 for (ZoneRulesProvider provider : PROVIDERS) { 358 changed |= provider.provideRefresh(); 359 } 360 return changed; 361 } 362 363 /** 364 * Constructor. 365 */ ZoneRulesProvider()366 protected ZoneRulesProvider() { 367 } 368 369 //----------------------------------------------------------------------- 370 /** 371 * SPI method to get the available zone IDs. 372 * <p> 373 * This obtains the IDs that this {@code ZoneRulesProvider} provides. 374 * A provider should provide data for at least one zone ID. 375 * <p> 376 * The returned zone IDs remain available and valid for the lifetime of the application. 377 * A dynamic provider may increase the set of IDs as more data becomes available. 378 * 379 * @return the set of zone IDs being provided, not null 380 * @throws ZoneRulesException if a problem occurs while providing the IDs 381 */ provideZoneIds()382 protected abstract Set<String> provideZoneIds(); 383 384 /** 385 * SPI method to get the rules for the zone ID. 386 * <p> 387 * This loads the rules for the specified zone ID. 388 * The provider implementation must validate that the zone ID is valid and 389 * available, throwing a {@code ZoneRulesException} if it is not. 390 * The result of the method in the valid case depends on the caching flag. 391 * <p> 392 * If the provider implementation is not dynamic, then the result of the 393 * method must be the non-null set of rules selected by the ID. 394 * <p> 395 * If the provider implementation is dynamic, then the flag gives the option 396 * of preventing the returned rules from being cached in {@link ZoneId}. 397 * When the flag is true, the provider is permitted to return null, where 398 * null will prevent the rules from being cached in {@code ZoneId}. 399 * When the flag is false, the provider must return non-null rules. 400 * 401 * @param zoneId the zone ID as defined by {@code ZoneId}, not null 402 * @param forCaching whether the rules are being queried for caching, 403 * true if the returned rules will be cached by {@code ZoneId}, 404 * false if they will be returned to the user without being cached in {@code ZoneId} 405 * @return the rules, null if {@code forCaching} is true and this 406 * is a dynamic provider that wants to prevent caching in {@code ZoneId}, 407 * otherwise not null 408 * @throws ZoneRulesException if rules cannot be obtained for the zone ID 409 */ provideRules(String zoneId, boolean forCaching)410 protected abstract ZoneRules provideRules(String zoneId, boolean forCaching); 411 412 /** 413 * SPI method to get the history of rules for the zone ID. 414 * <p> 415 * This returns a map of historical rules keyed by a version string. 416 * The exact meaning and format of the version is provider specific. 417 * The version must follow lexicographical order, thus the returned map will 418 * be order from the oldest known rules to the newest available rules. 419 * The default 'TZDB' group uses version numbering consisting of the year 420 * followed by a letter, such as '2009e' or '2012f'. 421 * <p> 422 * Implementations must provide a result for each valid zone ID, however 423 * they do not have to provide a history of rules. 424 * Thus the map will contain at least one element, and will only contain 425 * more than one element if historical rule information is available. 426 * <p> 427 * The returned versions remain available and valid for the lifetime of the application. 428 * A dynamic provider may increase the set of versions as more data becomes available. 429 * 430 * @param zoneId the zone ID as defined by {@code ZoneId}, not null 431 * @return a modifiable copy of the history of the rules for the ID, sorted 432 * from oldest to newest, not null 433 * @throws ZoneRulesException if history cannot be obtained for the zone ID 434 */ provideVersions(String zoneId)435 protected abstract NavigableMap<String, ZoneRules> provideVersions(String zoneId); 436 437 /** 438 * SPI method to refresh the rules from the underlying data provider. 439 * <p> 440 * This method provides the opportunity for a provider to dynamically 441 * recheck the underlying data provider to find the latest rules. 442 * This could be used to load new rules without stopping the JVM. 443 * Dynamic behavior is entirely optional and most providers do not support it. 444 * <p> 445 * This implementation returns false. 446 * 447 * @return true if the rules were updated 448 * @throws ZoneRulesException if an error occurs during the refresh 449 */ provideRefresh()450 protected boolean provideRefresh() { 451 return false; 452 } 453 454 } 455