1 /* 2 * Copyright (c) 2012, 2015, 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) 2007-2012, 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; 63 64 import java.io.IOException; 65 import java.io.ObjectInputStream; 66 import static java.time.LocalTime.NANOS_PER_MINUTE; 67 import static java.time.LocalTime.NANOS_PER_SECOND; 68 import static java.time.LocalTime.NANOS_PER_MILLI; 69 import java.io.Serializable; 70 import java.util.Objects; 71 import java.util.TimeZone; 72 import jdk.internal.misc.VM; 73 74 /** 75 * A clock providing access to the current instant, date and time using a time-zone. 76 * <p> 77 * Instances of this class are used to find the current instant, which can be 78 * interpreted using the stored time-zone to find the current date and time. 79 * As such, a clock can be used instead of {@link System#currentTimeMillis()} 80 * and {@link TimeZone#getDefault()}. 81 * <p> 82 * Use of a {@code Clock} is optional. All key date-time classes also have a 83 * {@code now()} factory method that uses the system clock in the default time zone. 84 * The primary purpose of this abstraction is to allow alternate clocks to be 85 * plugged in as and when required. Applications use an object to obtain the 86 * current time rather than a static method. This can simplify testing. 87 * <p> 88 * Best practice for applications is to pass a {@code Clock} into any method 89 * that requires the current instant. A dependency injection framework is one 90 * way to achieve this: 91 * <pre> 92 * public class MyBean { 93 * private Clock clock; // dependency inject 94 * ... 95 * public void process(LocalDate eventDate) { 96 * if (eventDate.isBefore(LocalDate.now(clock)) { 97 * ... 98 * } 99 * } 100 * } 101 * </pre> 102 * This approach allows an alternate clock, such as {@link #fixed(Instant, ZoneId) fixed} 103 * or {@link #offset(Clock, Duration) offset} to be used during testing. 104 * <p> 105 * The {@code system} factory methods provide clocks based on the best available 106 * system clock This may use {@link System#currentTimeMillis()}, or a higher 107 * resolution clock if one is available. 108 * 109 * @implSpec 110 * This abstract class must be implemented with care to ensure other classes operate correctly. 111 * All implementations that can be instantiated must be final, immutable and thread-safe. 112 * <p> 113 * The principal methods are defined to allow the throwing of an exception. 114 * In normal use, no exceptions will be thrown, however one possible implementation would be to 115 * obtain the time from a central time server across the network. Obviously, in this case the 116 * lookup could fail, and so the method is permitted to throw an exception. 117 * <p> 118 * The returned instants from {@code Clock} work on a time-scale that ignores leap seconds, 119 * as described in {@link Instant}. If the implementation wraps a source that provides leap 120 * second information, then a mechanism should be used to "smooth" the leap second. 121 * The Java Time-Scale mandates the use of UTC-SLS, however clock implementations may choose 122 * how accurate they are with the time-scale so long as they document how they work. 123 * Implementations are therefore not required to actually perform the UTC-SLS slew or to 124 * otherwise be aware of leap seconds. 125 * <p> 126 * Implementations should implement {@code Serializable} wherever possible and must 127 * document whether or not they do support serialization. 128 * 129 * @implNote 130 * The clock implementation provided here is based on the same underlying clock 131 * as {@link System#currentTimeMillis()}, but may have a precision finer than 132 * milliseconds if available. 133 * However, little to no guarantee is provided about the accuracy of the 134 * underlying clock. Applications requiring a more accurate clock must implement 135 * this abstract class themselves using a different external clock, such as an 136 * NTP server. 137 * 138 * @since 1.8 139 */ 140 public abstract class Clock { 141 142 /** 143 * Obtains a clock that returns the current instant using the best available 144 * system clock, converting to date and time using the UTC time-zone. 145 * <p> 146 * This clock, rather than {@link #systemDefaultZone()}, should be used when 147 * you need the current instant without the date or time. 148 * <p> 149 * This clock is based on the best available system clock. 150 * This may use {@link System#currentTimeMillis()}, or a higher resolution 151 * clock if one is available. 152 * <p> 153 * Conversion from instant to date or time uses the {@linkplain ZoneOffset#UTC UTC time-zone}. 154 * <p> 155 * The returned implementation is immutable, thread-safe and {@code Serializable}. 156 * It is equivalent to {@code system(ZoneOffset.UTC)}. 157 * 158 * @return a clock that uses the best available system clock in the UTC zone, not null 159 */ 160 public static Clock systemUTC() { 161 return SystemClock.UTC; 162 } 163 164 /** 165 * Obtains a clock that returns the current instant using the best available 166 * system clock, converting to date and time using the default time-zone. 167 * <p> 168 * This clock is based on the best available system clock. 169 * This may use {@link System#currentTimeMillis()}, or a higher resolution 170 * clock if one is available. 171 * <p> 172 * Using this method hard codes a dependency to the default time-zone into your application. 173 * It is recommended to avoid this and use a specific time-zone whenever possible. 174 * The {@link #systemUTC() UTC clock} should be used when you need the current instant 175 * without the date or time. 176 * <p> 177 * The returned implementation is immutable, thread-safe and {@code Serializable}. 178 * It is equivalent to {@code system(ZoneId.systemDefault())}. 179 * 180 * @return a clock that uses the best available system clock in the default zone, not null 181 * @see ZoneId#systemDefault() 182 */ 183 public static Clock systemDefaultZone() { 184 return new SystemClock(ZoneId.systemDefault()); 185 } 186 187 /** 188 * Obtains a clock that returns the current instant using the best available 189 * system clock. 190 * <p> 191 * This clock is based on the best available system clock. 192 * This may use {@link System#currentTimeMillis()}, or a higher resolution 193 * clock if one is available. 194 * <p> 195 * Conversion from instant to date or time uses the specified time-zone. 196 * <p> 197 * The returned implementation is immutable, thread-safe and {@code Serializable}. 198 * 199 * @param zone the time-zone to use to convert the instant to date-time, not null 200 * @return a clock that uses the best available system clock in the specified zone, not null 201 */ 202 public static Clock system(ZoneId zone) { 203 Objects.requireNonNull(zone, "zone"); 204 if (zone == ZoneOffset.UTC) { 205 return SystemClock.UTC; 206 } 207 return new SystemClock(zone); 208 } 209 210 //------------------------------------------------------------------------- 211 /** 212 * Obtains a clock that returns the current instant ticking in whole milliseconds 213 * using the best available system clock. 214 * <p> 215 * This clock will always have the nano-of-second field truncated to milliseconds. 216 * This ensures that the visible time ticks in whole milliseconds. 217 * The underlying clock is the best available system clock, equivalent to 218 * using {@link #system(ZoneId)}. 219 * <p> 220 * Implementations may use a caching strategy for performance reasons. 221 * As such, it is possible that the start of the millisecond observed via this 222 * clock will be later than that observed directly via the underlying clock. 223 * <p> 224 * The returned implementation is immutable, thread-safe and {@code Serializable}. 225 * It is equivalent to {@code tick(system(zone), Duration.ofMillis(1))}. 226 * 227 * @param zone the time-zone to use to convert the instant to date-time, not null 228 * @return a clock that ticks in whole milliseconds using the specified zone, not null 229 * @since 9 230 */ 231 public static Clock tickMillis(ZoneId zone) { 232 return new TickClock(system(zone), NANOS_PER_MILLI); 233 } 234 235 //------------------------------------------------------------------------- 236 /** 237 * Obtains a clock that returns the current instant ticking in whole seconds 238 * using the best available system clock. 239 * <p> 240 * This clock will always have the nano-of-second field set to zero. 241 * This ensures that the visible time ticks in whole seconds. 242 * The underlying clock is the best available system clock, equivalent to 243 * using {@link #system(ZoneId)}. 244 * <p> 245 * Implementations may use a caching strategy for performance reasons. 246 * As such, it is possible that the start of the second observed via this 247 * clock will be later than that observed directly via the underlying clock. 248 * <p> 249 * The returned implementation is immutable, thread-safe and {@code Serializable}. 250 * It is equivalent to {@code tick(system(zone), Duration.ofSeconds(1))}. 251 * 252 * @param zone the time-zone to use to convert the instant to date-time, not null 253 * @return a clock that ticks in whole seconds using the specified zone, not null 254 */ 255 public static Clock tickSeconds(ZoneId zone) { 256 return new TickClock(system(zone), NANOS_PER_SECOND); 257 } 258 259 /** 260 * Obtains a clock that returns the current instant ticking in whole minutes 261 * using the best available system clock. 262 * <p> 263 * This clock will always have the nano-of-second and second-of-minute fields set to zero. 264 * This ensures that the visible time ticks in whole minutes. 265 * The underlying clock is the best available system clock, equivalent to 266 * using {@link #system(ZoneId)}. 267 * <p> 268 * Implementations may use a caching strategy for performance reasons. 269 * As such, it is possible that the start of the minute observed via this 270 * clock will be later than that observed directly via the underlying clock. 271 * <p> 272 * The returned implementation is immutable, thread-safe and {@code Serializable}. 273 * It is equivalent to {@code tick(system(zone), Duration.ofMinutes(1))}. 274 * 275 * @param zone the time-zone to use to convert the instant to date-time, not null 276 * @return a clock that ticks in whole minutes using the specified zone, not null 277 */ 278 public static Clock tickMinutes(ZoneId zone) { 279 return new TickClock(system(zone), NANOS_PER_MINUTE); 280 } 281 282 /** 283 * Obtains a clock that returns instants from the specified clock truncated 284 * to the nearest occurrence of the specified duration. 285 * <p> 286 * This clock will only tick as per the specified duration. Thus, if the duration 287 * is half a second, the clock will return instants truncated to the half second. 288 * <p> 289 * The tick duration must be positive. If it has a part smaller than a whole 290 * millisecond, then the whole duration must divide into one second without 291 * leaving a remainder. All normal tick durations will match these criteria, 292 * including any multiple of hours, minutes, seconds and milliseconds, and 293 * sensible nanosecond durations, such as 20ns, 250,000ns and 500,000ns. 294 * <p> 295 * A duration of zero or one nanosecond would have no truncation effect. 296 * Passing one of these will return the underlying clock. 297 * <p> 298 * Implementations may use a caching strategy for performance reasons. 299 * As such, it is possible that the start of the requested duration observed 300 * via this clock will be later than that observed directly via the underlying clock. 301 * <p> 302 * The returned implementation is immutable, thread-safe and {@code Serializable} 303 * providing that the base clock is. 304 * 305 * @param baseClock the base clock to base the ticking clock on, not null 306 * @param tickDuration the duration of each visible tick, not negative, not null 307 * @return a clock that ticks in whole units of the duration, not null 308 * @throws IllegalArgumentException if the duration is negative, or has a 309 * part smaller than a whole millisecond such that the whole duration is not 310 * divisible into one second 311 * @throws ArithmeticException if the duration is too large to be represented as nanos 312 */ 313 public static Clock tick(Clock baseClock, Duration tickDuration) { 314 Objects.requireNonNull(baseClock, "baseClock"); 315 Objects.requireNonNull(tickDuration, "tickDuration"); 316 if (tickDuration.isNegative()) { 317 throw new IllegalArgumentException("Tick duration must not be negative"); 318 } 319 long tickNanos = tickDuration.toNanos(); 320 if (tickNanos % 1000_000 == 0) { 321 // ok, no fraction of millisecond 322 } else if (1000_000_000 % tickNanos == 0) { 323 // ok, divides into one second without remainder 324 } else { 325 throw new IllegalArgumentException("Invalid tick duration"); 326 } 327 if (tickNanos <= 1) { 328 return baseClock; 329 } 330 return new TickClock(baseClock, tickNanos); 331 } 332 333 //----------------------------------------------------------------------- 334 /** 335 * Obtains a clock that always returns the same instant. 336 * <p> 337 * This clock simply returns the specified instant. 338 * As such, it is not a clock in the conventional sense. 339 * The main use case for this is in testing, where the fixed clock ensures 340 * tests are not dependent on the current clock. 341 * <p> 342 * The returned implementation is immutable, thread-safe and {@code Serializable}. 343 * 344 * @param fixedInstant the instant to use as the clock, not null 345 * @param zone the time-zone to use to convert the instant to date-time, not null 346 * @return a clock that always returns the same instant, not null 347 */ 348 public static Clock fixed(Instant fixedInstant, ZoneId zone) { 349 Objects.requireNonNull(fixedInstant, "fixedInstant"); 350 Objects.requireNonNull(zone, "zone"); 351 return new FixedClock(fixedInstant, zone); 352 } 353 354 //------------------------------------------------------------------------- 355 /** 356 * Obtains a clock that returns instants from the specified clock with the 357 * specified duration added 358 * <p> 359 * This clock wraps another clock, returning instants that are later by the 360 * specified duration. If the duration is negative, the instants will be 361 * earlier than the current date and time. 362 * The main use case for this is to simulate running in the future or in the past. 363 * <p> 364 * A duration of zero would have no offsetting effect. 365 * Passing zero will return the underlying clock. 366 * <p> 367 * The returned implementation is immutable, thread-safe and {@code Serializable} 368 * providing that the base clock is. 369 * 370 * @param baseClock the base clock to add the duration to, not null 371 * @param offsetDuration the duration to add, not null 372 * @return a clock based on the base clock with the duration added, not null 373 */ 374 public static Clock offset(Clock baseClock, Duration offsetDuration) { 375 Objects.requireNonNull(baseClock, "baseClock"); 376 Objects.requireNonNull(offsetDuration, "offsetDuration"); 377 if (offsetDuration.equals(Duration.ZERO)) { 378 return baseClock; 379 } 380 return new OffsetClock(baseClock, offsetDuration); 381 } 382 383 //----------------------------------------------------------------------- 384 /** 385 * Constructor accessible by subclasses. 386 */ 387 protected Clock() { 388 } 389 390 //----------------------------------------------------------------------- 391 /** 392 * Gets the time-zone being used to create dates and times. 393 * <p> 394 * A clock will typically obtain the current instant and then convert that 395 * to a date or time using a time-zone. This method returns the time-zone used. 396 * 397 * @return the time-zone being used to interpret instants, not null 398 */ 399 public abstract ZoneId getZone(); 400 401 /** 402 * Returns a copy of this clock with a different time-zone. 403 * <p> 404 * A clock will typically obtain the current instant and then convert that 405 * to a date or time using a time-zone. This method returns a clock with 406 * similar properties but using a different time-zone. 407 * 408 * @param zone the time-zone to change to, not null 409 * @return a clock based on this clock with the specified time-zone, not null 410 */ 411 public abstract Clock withZone(ZoneId zone); 412 413 //------------------------------------------------------------------------- 414 /** 415 * Gets the current millisecond instant of the clock. 416 * <p> 417 * This returns the millisecond-based instant, measured from 1970-01-01T00:00Z (UTC). 418 * This is equivalent to the definition of {@link System#currentTimeMillis()}. 419 * <p> 420 * Most applications should avoid this method and use {@link Instant} to represent 421 * an instant on the time-line rather than a raw millisecond value. 422 * This method is provided to allow the use of the clock in high performance use cases 423 * where the creation of an object would be unacceptable. 424 * <p> 425 * The default implementation currently calls {@link #instant}. 426 * 427 * @return the current millisecond instant from this clock, measured from 428 * the Java epoch of 1970-01-01T00:00Z (UTC), not null 429 * @throws DateTimeException if the instant cannot be obtained, not thrown by most implementations 430 */ 431 public long millis() { 432 return instant().toEpochMilli(); 433 } 434 435 //----------------------------------------------------------------------- 436 /** 437 * Gets the current instant of the clock. 438 * <p> 439 * This returns an instant representing the current instant as defined by the clock. 440 * 441 * @return the current instant from this clock, not null 442 * @throws DateTimeException if the instant cannot be obtained, not thrown by most implementations 443 */ 444 public abstract Instant instant(); 445 446 //----------------------------------------------------------------------- 447 /** 448 * Checks if this clock is equal to another clock. 449 * <p> 450 * Clocks should override this method to compare equals based on 451 * their state and to meet the contract of {@link Object#equals}. 452 * If not overridden, the behavior is defined by {@link Object#equals} 453 * 454 * @param obj the object to check, null returns false 455 * @return true if this is equal to the other clock 456 */ 457 @Override 458 public boolean equals(Object obj) { 459 return super.equals(obj); 460 } 461 462 /** 463 * A hash code for this clock. 464 * <p> 465 * Clocks should override this method based on 466 * their state and to meet the contract of {@link Object#hashCode}. 467 * If not overridden, the behavior is defined by {@link Object#hashCode} 468 * 469 * @return a suitable hash code 470 */ 471 @Override 472 public int hashCode() { 473 return super.hashCode(); 474 } 475 476 //----------------------------------------------------------------------- 477 /** 478 * Implementation of a clock that always returns the latest time from 479 * {@link System#currentTimeMillis()}. 480 */ 481 static final class SystemClock extends Clock implements Serializable { 482 private static final long serialVersionUID = 6740630888130243051L; 483 private static final long OFFSET_SEED = 484 System.currentTimeMillis()/1000 - 1024; // initial offest 485 static final SystemClock UTC = new SystemClock(ZoneOffset.UTC); 486 487 private final ZoneId zone; 488 // We don't actually need a volatile here. 489 // We don't care if offset is set or read concurrently by multiple 490 // threads - we just need a value which is 'recent enough' - in other 491 // words something that has been updated at least once in the last 492 // 2^32 secs (~136 years). And even if we by chance see an invalid 493 // offset, the worst that can happen is that we will get a -1 value 494 // from getNanoTimeAdjustment, forcing us to update the offset 495 // once again. 496 private transient long offset; 497 498 SystemClock(ZoneId zone) { 499 this.zone = zone; 500 this.offset = OFFSET_SEED; 501 } 502 @Override 503 public ZoneId getZone() { 504 return zone; 505 } 506 @Override 507 public Clock withZone(ZoneId zone) { 508 if (zone.equals(this.zone)) { // intentional NPE 509 return this; 510 } 511 return new SystemClock(zone); 512 } 513 @Override 514 public long millis() { 515 // System.currentTimeMillis() and VM.getNanoTimeAdjustment(offset) 516 // use the same time source - System.currentTimeMillis() simply 517 // limits the resolution to milliseconds. 518 // So we take the faster path and call System.currentTimeMillis() 519 // directly - in order to avoid the performance penalty of 520 // VM.getNanoTimeAdjustment(offset) which is less efficient. 521 return System.currentTimeMillis(); 522 } 523 @Override 524 public Instant instant() { 525 // Take a local copy of offset. offset can be updated concurrently 526 // by other threads (even if we haven't made it volatile) so we will 527 // work with a local copy. 528 long localOffset = offset; 529 long adjustment = VM.getNanoTimeAdjustment(localOffset); 530 531 if (adjustment == -1) { 532 // -1 is a sentinel value returned by VM.getNanoTimeAdjustment 533 // when the offset it is given is too far off the current UTC 534 // time. In principle, this should not happen unless the 535 // JVM has run for more than ~136 years (not likely) or 536 // someone is fiddling with the system time, or the offset is 537 // by chance at 1ns in the future (very unlikely). 538 // We can easily recover from all these conditions by bringing 539 // back the offset in range and retry. 540 541 // bring back the offset in range. We use -1024 to make 542 // it more unlikely to hit the 1ns in the future condition. 543 localOffset = System.currentTimeMillis()/1000 - 1024; 544 545 // retry 546 adjustment = VM.getNanoTimeAdjustment(localOffset); 547 548 if (adjustment == -1) { 549 // Should not happen: we just recomputed a new offset. 550 // It should have fixed the issue. 551 throw new InternalError("Offset " + localOffset + " is not in range"); 552 } else { 553 // OK - recovery succeeded. Update the offset for the 554 // next call... 555 offset = localOffset; 556 } 557 } 558 return Instant.ofEpochSecond(localOffset, adjustment); 559 } 560 @Override 561 public boolean equals(Object obj) { 562 if (obj instanceof SystemClock) { 563 return zone.equals(((SystemClock) obj).zone); 564 } 565 return false; 566 } 567 @Override 568 public int hashCode() { 569 return zone.hashCode() + 1; 570 } 571 @Override 572 public String toString() { 573 return "SystemClock[" + zone + "]"; 574 } 575 private void readObject(ObjectInputStream is) 576 throws IOException, ClassNotFoundException { 577 // ensure that offset is initialized 578 is.defaultReadObject(); 579 offset = OFFSET_SEED; 580 } 581 } 582 583 //----------------------------------------------------------------------- 584 /** 585 * Implementation of a clock that always returns the same instant. 586 * This is typically used for testing. 587 */ 588 static final class FixedClock extends Clock implements Serializable { 589 private static final long serialVersionUID = 7430389292664866958L; 590 private final Instant instant; 591 private final ZoneId zone; 592 593 FixedClock(Instant fixedInstant, ZoneId zone) { 594 this.instant = fixedInstant; 595 this.zone = zone; 596 } 597 @Override 598 public ZoneId getZone() { 599 return zone; 600 } 601 @Override 602 public Clock withZone(ZoneId zone) { 603 if (zone.equals(this.zone)) { // intentional NPE 604 return this; 605 } 606 return new FixedClock(instant, zone); 607 } 608 @Override 609 public long millis() { 610 return instant.toEpochMilli(); 611 } 612 @Override 613 public Instant instant() { 614 return instant; 615 } 616 @Override 617 public boolean equals(Object obj) { 618 if (obj instanceof FixedClock) { 619 FixedClock other = (FixedClock) obj; 620 return instant.equals(other.instant) && zone.equals(other.zone); 621 } 622 return false; 623 } 624 @Override 625 public int hashCode() { 626 return instant.hashCode() ^ zone.hashCode(); 627 } 628 @Override 629 public String toString() { 630 return "FixedClock[" + instant + "," + zone + "]"; 631 } 632 } 633 634 //----------------------------------------------------------------------- 635 /** 636 * Implementation of a clock that adds an offset to an underlying clock. 637 */ 638 static final class OffsetClock extends Clock implements Serializable { 639 private static final long serialVersionUID = 2007484719125426256L; 640 private final Clock baseClock; 641 private final Duration offset; 642 643 OffsetClock(Clock baseClock, Duration offset) { 644 this.baseClock = baseClock; 645 this.offset = offset; 646 } 647 @Override 648 public ZoneId getZone() { 649 return baseClock.getZone(); 650 } 651 @Override 652 public Clock withZone(ZoneId zone) { 653 if (zone.equals(baseClock.getZone())) { // intentional NPE 654 return this; 655 } 656 return new OffsetClock(baseClock.withZone(zone), offset); 657 } 658 @Override 659 public long millis() { 660 return Math.addExact(baseClock.millis(), offset.toMillis()); 661 } 662 @Override 663 public Instant instant() { 664 return baseClock.instant().plus(offset); 665 } 666 @Override 667 public boolean equals(Object obj) { 668 if (obj instanceof OffsetClock) { 669 OffsetClock other = (OffsetClock) obj; 670 return baseClock.equals(other.baseClock) && offset.equals(other.offset); 671 } 672 return false; 673 } 674 @Override 675 public int hashCode() { 676 return baseClock.hashCode() ^ offset.hashCode(); 677 } 678 @Override 679 public String toString() { 680 return "OffsetClock[" + baseClock + "," + offset + "]"; 681 } 682 } 683 684 //----------------------------------------------------------------------- 685 /** 686 * Implementation of a clock that adds an offset to an underlying clock. 687 */ 688 static final class TickClock extends Clock implements Serializable { 689 private static final long serialVersionUID = 6504659149906368850L; 690 private final Clock baseClock; 691 private final long tickNanos; 692 693 TickClock(Clock baseClock, long tickNanos) { 694 this.baseClock = baseClock; 695 this.tickNanos = tickNanos; 696 } 697 @Override 698 public ZoneId getZone() { 699 return baseClock.getZone(); 700 } 701 @Override 702 public Clock withZone(ZoneId zone) { 703 if (zone.equals(baseClock.getZone())) { // intentional NPE 704 return this; 705 } 706 return new TickClock(baseClock.withZone(zone), tickNanos); 707 } 708 @Override 709 public long millis() { 710 long millis = baseClock.millis(); 711 return millis - Math.floorMod(millis, tickNanos / 1000_000L); 712 } 713 @Override 714 public Instant instant() { 715 if ((tickNanos % 1000_000) == 0) { 716 long millis = baseClock.millis(); 717 return Instant.ofEpochMilli(millis - Math.floorMod(millis, tickNanos / 1000_000L)); 718 } 719 Instant instant = baseClock.instant(); 720 long nanos = instant.getNano(); 721 long adjust = Math.floorMod(nanos, tickNanos); 722 return instant.minusNanos(adjust); 723 } 724 @Override 725 public boolean equals(Object obj) { 726 if (obj instanceof TickClock) { 727 TickClock other = (TickClock) obj; 728 return baseClock.equals(other.baseClock) && tickNanos == other.tickNanos; 729 } 730 return false; 731 } 732 @Override 733 public int hashCode() { 734 return baseClock.hashCode() ^ ((int) (tickNanos ^ (tickNanos >>> 32))); 735 } 736 @Override 737 public String toString() { 738 return "TickClock[" + baseClock + "," + Duration.ofNanos(tickNanos) + "]"; 739 } 740 } 741 742 }