1 /*
2 * Copyright (c) 2012, 2013, 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 static java.time.LocalTime.NANOS_PER_SECOND;
65 import static java.time.LocalTime.SECONDS_PER_DAY;
66 import static java.time.LocalTime.SECONDS_PER_HOUR;
67 import static java.time.LocalTime.SECONDS_PER_MINUTE;
68 import static java.time.temporal.ChronoField.INSTANT_SECONDS;
69 import static java.time.temporal.ChronoField.MICRO_OF_SECOND;
70 import static java.time.temporal.ChronoField.MILLI_OF_SECOND;
71 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
72 import static java.time.temporal.ChronoUnit.NANOS;
73
74 import java.io.DataInput;
75 import java.io.DataOutput;
76 import java.io.IOException;
77 import java.io.InvalidObjectException;
78 import java.io.ObjectStreamException;
79 import java.io.Serializable;
80 import java.time.format.DateTimeFormatter;
81 import java.time.format.DateTimeParseException;
82 import java.time.temporal.ChronoField;
83 import java.time.temporal.ChronoUnit;
84 import java.time.temporal.Queries;
85 import java.time.temporal.Temporal;
86 import java.time.temporal.TemporalAccessor;
87 import java.time.temporal.TemporalAdjuster;
88 import java.time.temporal.TemporalAmount;
89 import java.time.temporal.TemporalField;
90 import java.time.temporal.TemporalQuery;
91 import java.time.temporal.TemporalUnit;
92 import java.time.temporal.ValueRange;
93 import java.util.Objects;
94
95 /**
96 * An instantaneous point on the time-line.
97 * <p>
98 * This class models a single instantaneous point on the time-line.
99 * This might be used to record event time-stamps in the application.
100 * <p>
101 * For practicality, the instant is stored with some constraints.
102 * The measurable time-line is restricted to the number of seconds that can be held
103 * in a {@code long}. This is greater than the current estimated age of the universe.
104 * The instant is stored to nanosecond resolution.
105 * <p>
106 * The range of an instant requires the storage of a number larger than a {@code long}.
107 * To achieve this, the class stores a {@code long} representing epoch-seconds and an
108 * {@code int} representing nanosecond-of-second, which will always be between 0 and 999,999,999.
109 * The epoch-seconds are measured from the standard Java epoch of {@code 1970-01-01T00:00:00Z}
110 * where instants after the epoch have positive values, and earlier instants have negative values.
111 * For both the epoch-second and nanosecond parts, a larger value is always later on the time-line
112 * than a smaller value.
113 *
114 * <h3>Time-scale</h3>
115 * <p>
116 * The length of the solar day is the standard way that humans measure time.
117 * This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds,
118 * forming a 86400 second day.
119 * <p>
120 * Modern timekeeping is based on atomic clocks which precisely define an SI second
121 * relative to the transitions of a Caesium atom. The length of an SI second was defined
122 * to be very close to the 86400th fraction of a day.
123 * <p>
124 * Unfortunately, as the Earth rotates the length of the day varies.
125 * In addition, over time the average length of the day is getting longer as the Earth slows.
126 * As a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds.
127 * The actual length of any given day and the amount by which the Earth is slowing
128 * are not predictable and can only be determined by measurement.
129 * The UT1 time-scale captures the accurate length of day, but is only available some
130 * time after the day has completed.
131 * <p>
132 * The UTC time-scale is a standard approach to bundle up all the additional fractions
133 * of a second from UT1 into whole seconds, known as <i>leap-seconds</i>.
134 * A leap-second may be added or removed depending on the Earth's rotational changes.
135 * As such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where
136 * necessary in order to keep the day aligned with the Sun.
137 * <p>
138 * The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds.
139 * Between 1958 and 1972, the definition of UTC was complex, with minor sub-second leaps and
140 * alterations to the length of the notional second. As of 2012, discussions are underway
141 * to change the definition of UTC again, with the potential to remove leap seconds or
142 * introduce other changes.
143 * <p>
144 * Given the complexity of accurate timekeeping described above, this Java API defines
145 * its own time-scale with a simplification. The Java time-scale is defined as follows:
146 * <p><ul>
147 * <li>midday will always be exactly as defined by the agreed international civil time</li>
148 * <li>other times during the day will be broadly in line with the agreed international civil time</li>
149 * <li>the day will be divided into exactly 86400 subdivisions, referred to as "seconds"</li>
150 * <li>the Java "second" may differ from an SI second</li>
151 * </ul><p>
152 * Agreed international civil time is the base time-scale agreed by international convention,
153 * which in 2012 is UTC (with leap-seconds).
154 * <p>
155 * In 2012, the definition of the Java time-scale is the same as UTC for all days except
156 * those where a leap-second occurs. On days where a leap-second does occur, the time-scale
157 * effectively eliminates the leap-second, maintaining the fiction of 86400 seconds in the day.
158 * <p>
159 * The main benefit of always dividing the day into 86400 subdivisions is that it matches the
160 * expectations of most users of the API. The alternative is to force every user to understand
161 * what a leap second is and to force them to have special logic to handle them.
162 * Most applications do not have access to a clock that is accurate enough to record leap-seconds.
163 * Most applications also do not have a problem with a second being a very small amount longer or
164 * shorter than a real SI second during a leap-second.
165 * <p>
166 * If an application does have access to an accurate clock that reports leap-seconds, then the
167 * recommended technique to implement the Java time-scale is to use the UTC-SLS convention.
168 * <a href="http://www.cl.cam.ac.uk/~mgk25/time/utc-sls/">UTC-SLS</a> effectively smoothes the
169 * leap-second over the last 1000 seconds of the day, making each of the last 1000 "seconds"
170 * 1/1000th longer or shorter than a real SI second.
171 * <p>
172 * One final problem is the definition of the agreed international civil time before the
173 * introduction of modern UTC in 1972. This includes the Java epoch of {@code 1970-01-01}.
174 * It is intended that instants before 1972 be interpreted based on the solar day divided
175 * into 86400 subdivisions.
176 * <p>
177 * The Java time-scale is used for all date-time classes.
178 * This includes {@code Instant}, {@code LocalDate}, {@code LocalTime}, {@code OffsetDateTime},
179 * {@code ZonedDateTime} and {@code Duration}.
180 *
181 * <h3>Specification for implementors</h3>
182 * This class is immutable and thread-safe.
183 *
184 * @since 1.8
185 */
186 public final class Instant
187 implements Temporal, TemporalAdjuster, Comparable<Instant>, Serializable {
188
189 /**
190 * Constant for the 1970-01-01T00:00:00Z epoch instant.
191 */
192 public static final Instant EPOCH = new Instant(0, 0);
193 /**
194 * The minimum supported epoch second.
195 */
196 private static final long MIN_SECOND = -31557014167219200L;
197 /**
198 * The maximum supported epoch second.
199 */
200 private static final long MAX_SECOND = 31556889864403199L;
201 /**
202 * The minimum supported {@code Instant}, '-1000000000-01-01T00:00Z'.
203 * This could be used by an application as a "far past" instant.
204 * <p>
205 * This is one year earlier than the minimum {@code LocalDateTime}.
206 * This provides sufficient values to handle the range of {@code ZoneOffset}
207 * which affect the instant in addition to the local date-time.
208 * The value is also chosen such that the value of the year fits in
209 * an {@code int}.
210 */
211 public static final Instant MIN = Instant.ofEpochSecond(MIN_SECOND, 0);
212 /**
213 * The minimum supported {@code Instant}, '-1000000000-01-01T00:00Z'.
214 * This could be used by an application as a "far future" instant.
215 * <p>
216 * This is one year later than the maximum {@code LocalDateTime}.
217 * This provides sufficient values to handle the range of {@code ZoneOffset}
218 * which affect the instant in addition to the local date-time.
219 * The value is also chosen such that the value of the year fits in
220 * an {@code int}.
221 */
222 public static final Instant MAX = Instant.ofEpochSecond(MAX_SECOND, 999_999_999);
223
224 /**
225 * Serialization version.
226 */
227 private static final long serialVersionUID = -665713676816604388L;
228
229 /**
230 * The number of seconds from the epoch of 1970-01-01T00:00:00Z.
231 */
232 private final long seconds;
233 /**
234 * The number of nanoseconds, later along the time-line, from the seconds field.
235 * This is always positive, and never exceeds 999,999,999.
236 */
237 private final int nanos;
238
239 //-----------------------------------------------------------------------
240 /**
241 * Obtains the current instant from the system clock.
242 * <p>
243 * This will query the {@link Clock#systemUTC() system UTC clock} to
244 * obtain the current instant.
245 * <p>
246 * Using this method will prevent the ability to use an alternate time-source for
247 * testing because the clock is effectively hard-coded.
248 *
249 * @return the current instant using the system clock, not null
250 */
251 public static Instant now() {
252 return Clock.systemUTC().instant();
253 }
254
255 /**
256 * Obtains the current instant from the specified clock.
257 * <p>
258 * This will query the specified clock to obtain the current time.
259 * <p>
260 * Using this method allows the use of an alternate clock for testing.
261 * The alternate clock may be introduced using {@link Clock dependency injection}.
262 *
263 * @param clock the clock to use, not null
264 * @return the current instant, not null
265 */
266 public static Instant now(Clock clock) {
267 Objects.requireNonNull(clock, "clock");
268 return clock.instant();
269 }
270
271 //-----------------------------------------------------------------------
272 /**
273 * Obtains an instance of {@code Instant} using seconds from the
274 * epoch of 1970-01-01T00:00:00Z.
275 * <p>
276 * The nanosecond field is set to zero.
277 *
278 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
279 * @return an instant, not null
280 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
281 */
282 public static Instant ofEpochSecond(long epochSecond) {
283 return create(epochSecond, 0);
284 }
285
286 /**
287 * Obtains an instance of {@code Instant} using seconds from the
288 * epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.
289 * <p>
290 * This method allows an arbitrary number of nanoseconds to be passed in.
291 * The factory will alter the values of the second and nanosecond in order
292 * to ensure that the stored nanosecond is in the range 0 to 999,999,999.
293 * For example, the following will result in the exactly the same instant:
294 * <pre>
295 * Instant.ofSeconds(3, 1);
296 * Instant.ofSeconds(4, -999_999_999);
297 * Instant.ofSeconds(2, 1000_000_001);
298 * </pre>
299 *
300 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
301 * @param nanoAdjustment the nanosecond adjustment to the number of seconds, positive or negative
302 * @return an instant, not null
303 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
304 * @throws ArithmeticException if numeric overflow occurs
305 */
306 public static Instant ofEpochSecond(long epochSecond, long nanoAdjustment) {
307 long secs = Math.addExact(epochSecond, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND));
308 int nos = (int)Math.floorMod(nanoAdjustment, NANOS_PER_SECOND);
309 return create(secs, nos);
310 }
311
312 /**
313 * Obtains an instance of {@code Instant} using milliseconds from the
314 * epoch of 1970-01-01T00:00:00Z.
315 * <p>
316 * The seconds and nanoseconds are extracted from the specified milliseconds.
317 *
318 * @param epochMilli the number of milliseconds from 1970-01-01T00:00:00Z
319 * @return an instant, not null
320 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
321 */
322 public static Instant ofEpochMilli(long epochMilli) {
323 long secs = Math.floorDiv(epochMilli, 1000);
324 int mos = (int)Math.floorMod(epochMilli, 1000);
325 return create(secs, mos * 1000_000);
326 }
327
328 //-----------------------------------------------------------------------
329 /**
330 * Obtains an instance of {@code Instant} from a temporal object.
331 * <p>
332 * This obtains an instant based on the specified temporal.
333 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
334 * which this factory converts to an instance of {@code Instant}.
335 * <p>
336 * The conversion extracts the {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS}
337 * and {@link ChronoField#NANO_OF_SECOND NANO_OF_SECOND} fields.
338 * <p>
339 * This method matches the signature of the functional interface {@link TemporalQuery}
340 * allowing it to be used as a query via method reference, {@code Instant::from}.
341 *
342 * @param temporal the temporal object to convert, not null
343 * @return the instant, not null
344 * @throws DateTimeException if unable to convert to an {@code Instant}
345 */
346 public static Instant from(TemporalAccessor temporal) {
347 long instantSecs = temporal.getLong(INSTANT_SECONDS);
348 int nanoOfSecond = temporal.get(NANO_OF_SECOND);
349 return Instant.ofEpochSecond(instantSecs, nanoOfSecond);
350 }
351
352 //-----------------------------------------------------------------------
353 /**
354 * Obtains an instance of {@code Instant} from a text string such as
355 * {@code 2007-12-03T10:15:30:00}.
356 * <p>
357 * The string must represent a valid instant in UTC and is parsed using
358 * {@link DateTimeFormatter#ISO_INSTANT}.
359 *
360 * @param text the text to parse, not null
361 * @return the parsed instant, not null
362 * @throws DateTimeParseException if the text cannot be parsed
363 */
364 public static Instant parse(final CharSequence text) {
365 return DateTimeFormatter.ISO_INSTANT.parse(text, Instant::from);
366 }
367
368 //-----------------------------------------------------------------------
369 /**
370 * Obtains an instance of {@code Instant} using seconds and nanoseconds.
371 *
372 * @param seconds the length of the duration in seconds
373 * @param nanoOfSecond the nano-of-second, from 0 to 999,999,999
374 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
375 */
376 private static Instant create(long seconds, int nanoOfSecond) {
377 if ((seconds | nanoOfSecond) == 0) {
378 return EPOCH;
379 }
380 if (seconds < MIN_SECOND || seconds > MAX_SECOND) {
381 throw new DateTimeException("Instant exceeds minimum or maximum instant");
382 }
383 return new Instant(seconds, nanoOfSecond);
384 }
385
386 /**
387 * Constructs an instance of {@code Instant} using seconds from the epoch of
388 * 1970-01-01T00:00:00Z and nanosecond fraction of second.
389 *
390 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
391 * @param nanos the nanoseconds within the second, must be positive
392 */
393 private Instant(long epochSecond, int nanos) {
394 super();
395 this.seconds = epochSecond;
396 this.nanos = nanos;
397 }
398
399 //-----------------------------------------------------------------------
400 /**
401 * Checks if the specified field is supported.
402 * <p>
403 * This checks if this instant can be queried for the specified field.
404 * If false, then calling the {@link #range(TemporalField) range} and
405 * {@link #get(TemporalField) get} methods will throw an exception.
406 * <p>
407 * If the field is a {@link ChronoField} then the query is implemented here.
408 * The supported fields are:
409 * <ul>
410 * <li>{@code NANO_OF_SECOND}
411 * <li>{@code MICRO_OF_SECOND}
412 * <li>{@code MILLI_OF_SECOND}
413 * <li>{@code INSTANT_SECONDS}
414 * </ul>
415 * All other {@code ChronoField} instances will return false.
416 * <p>
417 * If the field is not a {@code ChronoField}, then the result of this method
418 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
419 * passing {@code this} as the argument.
420 * Whether the field is supported is determined by the field.
421 *
422 * @param field the field to check, null returns false
423 * @return true if the field is supported on this instant, false if not
424 */
425 @Override
426 public boolean isSupported(TemporalField field) {
427 if (field instanceof ChronoField) {
428 return field == INSTANT_SECONDS || field == NANO_OF_SECOND || field == MICRO_OF_SECOND || field == MILLI_OF_SECOND;
429 }
430 return field != null && field.isSupportedBy(this);
431 }
432
433 /**
434 * Gets the range of valid values for the specified field.
435 * <p>
436 * The range object expresses the minimum and maximum valid values for a field.
437 * This instant is used to enhance the accuracy of the returned range.
438 * If it is not possible to return the range, because the field is not supported
439 * or for some other reason, an exception is thrown.
440 * <p>
441 * If the field is a {@link ChronoField} then the query is implemented here.
442 * The {@link #isSupported(TemporalField) supported fields} will return
443 * appropriate range instances.
444 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
445 * <p>
446 * If the field is not a {@code ChronoField}, then the result of this method
447 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
448 * passing {@code this} as the argument.
449 * Whether the range can be obtained is determined by the field.
450 *
451 * @param field the field to query the range for, not null
452 * @return the range of valid values for the field, not null
453 * @throws DateTimeException if the range for the field cannot be obtained
454 */
455 @Override // override for Javadoc
456 public ValueRange range(TemporalField field) {
457 return Temporal.super.range(field);
458 }
459
460 /**
461 * Gets the value of the specified field from this instant as an {@code int}.
462 * <p>
463 * This queries this instant for the value for the specified field.
464 * The returned value will always be within the valid range of values for the field.
465 * If it is not possible to return the value, because the field is not supported
466 * or for some other reason, an exception is thrown.
467 * <p>
468 * If the field is a {@link ChronoField} then the query is implemented here.
469 * The {@link #isSupported(TemporalField) supported fields} will return valid
470 * values based on this date-time, except {@code INSTANT_SECONDS} which is too
471 * large to fit in an {@code int} and throws a {@code DateTimeException}.
472 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
473 * <p>
474 * If the field is not a {@code ChronoField}, then the result of this method
475 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
476 * passing {@code this} as the argument. Whether the value can be obtained,
477 * and what the value represents, is determined by the field.
478 *
479 * @param field the field to get, not null
480 * @return the value for the field
481 * @throws DateTimeException if a value for the field cannot be obtained
482 * @throws ArithmeticException if numeric overflow occurs
483 */
484 @Override // override for Javadoc and performance
485 public int get(TemporalField field) {
486 if (field instanceof ChronoField) {
487 switch ((ChronoField) field) {
488 case NANO_OF_SECOND: return nanos;
489 case MICRO_OF_SECOND: return nanos / 1000;
490 case MILLI_OF_SECOND: return nanos / 1000_000;
491 case INSTANT_SECONDS: INSTANT_SECONDS.checkValidIntValue(seconds);
492 }
493 throw new DateTimeException("Unsupported field: " + field.getName());
494 }
495 return range(field).checkValidIntValue(field.getFrom(this), field);
496 }
497
498 /**
499 * Gets the value of the specified field from this instant as a {@code long}.
500 * <p>
501 * This queries this instant for the value for the specified field.
502 * If it is not possible to return the value, because the field is not supported
503 * or for some other reason, an exception is thrown.
504 * <p>
505 * If the field is a {@link ChronoField} then the query is implemented here.
506 * The {@link #isSupported(TemporalField) supported fields} will return valid
507 * values based on this date-time.
508 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
509 * <p>
510 * If the field is not a {@code ChronoField}, then the result of this method
511 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
512 * passing {@code this} as the argument. Whether the value can be obtained,
513 * and what the value represents, is determined by the field.
514 *
515 * @param field the field to get, not null
516 * @return the value for the field
517 * @throws DateTimeException if a value for the field cannot be obtained
518 * @throws ArithmeticException if numeric overflow occurs
519 */
520 @Override
521 public long getLong(TemporalField field) {
522 if (field instanceof ChronoField) {
523 switch ((ChronoField) field) {
524 case NANO_OF_SECOND: return nanos;
525 case MICRO_OF_SECOND: return nanos / 1000;
526 case MILLI_OF_SECOND: return nanos / 1000_000;
527 case INSTANT_SECONDS: return seconds;
528 }
529 throw new DateTimeException("Unsupported field: " + field.getName());
530 }
531 return field.getFrom(this);
532 }
533
534 //-----------------------------------------------------------------------
535 /**
536 * Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.
537 * <p>
538 * The epoch second count is a simple incrementing count of seconds where
539 * second 0 is 1970-01-01T00:00:00Z.
540 * The nanosecond part of the day is returned by {@code getNanosOfSecond}.
541 *
542 * @return the seconds from the epoch of 1970-01-01T00:00:00Z
543 */
544 public long getEpochSecond() {
545 return seconds;
546 }
547
548 /**
549 * Gets the number of nanoseconds, later along the time-line, from the start
550 * of the second.
551 * <p>
552 * The nanosecond-of-second value measures the total number of nanoseconds from
553 * the second returned by {@code getEpochSecond}.
554 *
555 * @return the nanoseconds within the second, always positive, never exceeds 999,999,999
556 */
557 public int getNano() {
558 return nanos;
559 }
560
561 //-------------------------------------------------------------------------
562 /**
563 * Returns an adjusted copy of this instant.
564 * <p>
565 * This returns an {@code Instant}, based on this one, with the instant adjusted.
566 * The adjustment takes place using the specified adjuster strategy object.
567 * Read the documentation of the adjuster to understand what adjustment will be made.
568 * <p>
569 * The result of this method is obtained by invoking the
570 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
571 * specified adjuster passing {@code this} as the argument.
572 * <p>
573 * This instance is immutable and unaffected by this method call.
574 *
575 * @param adjuster the adjuster to use, not null
576 * @return an {@code Instant} based on {@code this} with the adjustment made, not null
577 * @throws DateTimeException if the adjustment cannot be made
578 * @throws ArithmeticException if numeric overflow occurs
579 */
580 @Override
581 public Instant with(TemporalAdjuster adjuster) {
582 return (Instant) adjuster.adjustInto(this);
583 }
584
585 /**
586 * Returns a copy of this instant with the specified field set to a new value.
587 * <p>
588 * This returns an {@code Instant}, based on this one, with the value
589 * for the specified field changed.
590 * If it is not possible to set the value, because the field is not supported or for
591 * some other reason, an exception is thrown.
592 * <p>
593 * If the field is a {@link ChronoField} then the adjustment is implemented here.
594 * The supported fields behave as follows:
595 * <ul>
596 * <li>{@code NANO_OF_SECOND} -
597 * Returns an {@code Instant} with the specified nano-of-second.
598 * The epoch-second will be unchanged.
599 * <li>{@code MICRO_OF_SECOND} -
600 * Returns an {@code Instant} with the nano-of-second replaced by the specified
601 * micro-of-second multiplied by 1,000. The epoch-second will be unchanged.
602 * <li>{@code MILLI_OF_SECOND} -
603 * Returns an {@code Instant} with the nano-of-second replaced by the specified
604 * milli-of-second multiplied by 1,000,000. The epoch-second will be unchanged.
605 * <li>{@code INSTANT_SECONDS} -
606 * Returns an {@code Instant} with the specified epoch-second.
607 * The nano-of-second will be unchanged.
608 * </ul>
609 * <p>
610 * In all cases, if the new value is outside the valid range of values for the field
611 * then a {@code DateTimeException} will be thrown.
612 * <p>
613 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
614 * <p>
615 * If the field is not a {@code ChronoField}, then the result of this method
616 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
617 * passing {@code this} as the argument. In this case, the field determines
618 * whether and how to adjust the instant.
619 * <p>
620 * This instance is immutable and unaffected by this method call.
621 *
622 * @param field the field to set in the result, not null
623 * @param newValue the new value of the field in the result
624 * @return an {@code Instant} based on {@code this} with the specified field set, not null
625 * @throws DateTimeException if the field cannot be set
626 * @throws ArithmeticException if numeric overflow occurs
627 */
628 @Override
629 public Instant with(TemporalField field, long newValue) {
630 if (field instanceof ChronoField) {
631 ChronoField f = (ChronoField) field;
632 f.checkValidValue(newValue);
633 switch (f) {
634 case MILLI_OF_SECOND: {
635 int nval = (int) newValue * 1000_000;
636 return (nval != nanos ? create(seconds, nval) : this);
637 }
638 case MICRO_OF_SECOND: {
639 int nval = (int) newValue * 1000;
640 return (nval != nanos ? create(seconds, nval) : this);
641 }
642 case NANO_OF_SECOND: return (newValue != nanos ? create(seconds, (int) newValue) : this);
643 case INSTANT_SECONDS: return (newValue != seconds ? create(newValue, nanos) : this);
644 }
645 throw new DateTimeException("Unsupported field: " + field.getName());
646 }
647 return field.adjustInto(this, newValue);
648 }
649
650 //-----------------------------------------------------------------------
651 /**
652 * Returns a copy of this {@code Instant} truncated to the specified unit.
653 * <p>
654 * Truncating the instant returns a copy of the original with fields
655 * smaller than the specified unit set to zero.
656 * The fields are calculated on the basis of using a UTC offset as seen
657 * in {@code toString}.
658 * For example, truncating with the {@link ChronoUnit#MINUTES MINUTES} unit will
659 * round down to the nearest minute, setting the seconds and nanoseconds to zero.
660 * <p>
661 * The unit must have a {@linkplain TemporalUnit#getDuration() duration}
662 * that divides into the length of a standard day without remainder.
663 * This includes all supplied time units on {@link ChronoUnit} and
664 * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception.
665 * <p>
666 * This instance is immutable and unaffected by this method call.
667 *
668 * @param unit the unit to truncate to, not null
669 * @return an {@code Instant} based on this instant with the time truncated, not null
670 * @throws DateTimeException if the unit is invalid for truncation
671 */
672 public Instant truncatedTo(TemporalUnit unit) {
673 if (unit == ChronoUnit.NANOS) {
674 return this;
675 }
676 Duration unitDur = unit.getDuration();
677 if (unitDur.getSeconds() > LocalTime.SECONDS_PER_DAY) {
678 throw new DateTimeException("Unit is too large to be used for truncation");
679 }
680 long dur = unitDur.toNanos();
681 if ((LocalTime.NANOS_PER_DAY % dur) != 0) {
682 throw new DateTimeException("Unit must divide into a standard day without remainder");
683 }
684 long nod = (seconds % LocalTime.SECONDS_PER_DAY) * LocalTime.NANOS_PER_SECOND + nanos;
685 long result = (nod / dur) * dur;
686 return plusNanos(result - nod);
687 }
688
689 //-----------------------------------------------------------------------
690 /**
691 * Returns a copy of this instant with the specified amount added.
692 * <p>
693 * This returns an {@code Instant}, based on this one, with the specified amount added.
694 * The amount is typically {@link Duration} but may be any other type implementing
695 * the {@link TemporalAmount} interface.
696 * <p>
697 * The calculation is delegated to the amount object by calling
698 * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
699 * to implement the addition in any way it wishes, however it typically
700 * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
701 * of the amount implementation to determine if it can be successfully added.
702 * <p>
703 * This instance is immutable and unaffected by this method call.
704 *
705 * @param amountToAdd the amount to add, not null
706 * @return an {@code Instant} based on this instant with the addition made, not null
707 * @throws DateTimeException if the addition cannot be made
708 * @throws ArithmeticException if numeric overflow occurs
709 */
710 @Override
711 public Instant plus(TemporalAmount amountToAdd) {
712 return (Instant) amountToAdd.addTo(this);
713 }
714
715 /**
716 * Returns a copy of this instant with the specified amount added.
717 * <p>
718 * This returns an {@code Instant}, based on this one, with the amount
719 * in terms of the unit added. If it is not possible to add the amount, because the
720 * unit is not supported or for some other reason, an exception is thrown.
721 * <p>
722 * If the field is a {@link ChronoUnit} then the addition is implemented here.
723 * The supported fields behave as follows:
724 * <ul>
725 * <li>{@code NANOS} -
726 * Returns a {@code Instant} with the specified number of nanoseconds added.
727 * This is equivalent to {@link #plusNanos(long)}.
728 * <li>{@code MICROS} -
729 * Returns a {@code Instant} with the specified number of microseconds added.
730 * This is equivalent to {@link #plusNanos(long)} with the amount
731 * multiplied by 1,000.
732 * <li>{@code MILLIS} -
733 * Returns a {@code Instant} with the specified number of milliseconds added.
734 * This is equivalent to {@link #plusNanos(long)} with the amount
735 * multiplied by 1,000,000.
736 * <li>{@code SECONDS} -
737 * Returns a {@code Instant} with the specified number of seconds added.
738 * This is equivalent to {@link #plusSeconds(long)}.
739 * <li>{@code MINUTES} -
740 * Returns a {@code Instant} with the specified number of minutes added.
741 * This is equivalent to {@link #plusSeconds(long)} with the amount
742 * multiplied by 60.
743 * <li>{@code HOURS} -
744 * Returns a {@code Instant} with the specified number of hours added.
745 * This is equivalent to {@link #plusSeconds(long)} with the amount
746 * multiplied by 3,600.
747 * <li>{@code HALF_DAYS} -
748 * Returns a {@code Instant} with the specified number of half-days added.
749 * This is equivalent to {@link #plusSeconds(long)} with the amount
750 * multiplied by 43,200 (12 hours).
751 * <li>{@code DAYS} -
752 * Returns a {@code Instant} with the specified number of days added.
753 * This is equivalent to {@link #plusSeconds(long)} with the amount
754 * multiplied by 86,400 (24 hours).
755 * </ul>
756 * <p>
757 * All other {@code ChronoUnit} instances will throw a {@code DateTimeException}.
758 * <p>
759 * If the field is not a {@code ChronoUnit}, then the result of this method
760 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
761 * passing {@code this} as the argument. In this case, the unit determines
762 * whether and how to perform the addition.
763 * <p>
764 * This instance is immutable and unaffected by this method call.
765 *
766 * @param amountToAdd the amount of the unit to add to the result, may be negative
767 * @param unit the unit of the amount to add, not null
768 * @return an {@code Instant} based on this instant with the specified amount added, not null
769 * @throws DateTimeException if the addition cannot be made
770 * @throws ArithmeticException if numeric overflow occurs
771 */
772 @Override
773 public Instant plus(long amountToAdd, TemporalUnit unit) {
774 if (unit instanceof ChronoUnit) {
775 switch ((ChronoUnit) unit) {
776 case NANOS: return plusNanos(amountToAdd);
777 case MICROS: return plus(amountToAdd / 1000_000, (amountToAdd % 1000_000) * 1000);
778 case MILLIS: return plusMillis(amountToAdd);
779 case SECONDS: return plusSeconds(amountToAdd);
780 case MINUTES: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_MINUTE));
781 case HOURS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_HOUR));
782 case HALF_DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY / 2));
783 case DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY));
784 }
785 throw new DateTimeException("Unsupported unit: " + unit.getName());
786 }
787 return unit.addTo(this, amountToAdd);
788 }
789
790 //-----------------------------------------------------------------------
791 /**
792 * Returns a copy of this instant with the specified duration in seconds added.
793 * <p>
794 * This instance is immutable and unaffected by this method call.
795 *
796 * @param secondsToAdd the seconds to add, positive or negative
797 * @return an {@code Instant} based on this instant with the specified seconds added, not null
798 * @throws DateTimeException if the result exceeds the maximum or minimum instant
799 * @throws ArithmeticException if numeric overflow occurs
800 */
801 public Instant plusSeconds(long secondsToAdd) {
802 return plus(secondsToAdd, 0);
803 }
804
805 /**
806 * Returns a copy of this instant with the specified duration in milliseconds added.
807 * <p>
808 * This instance is immutable and unaffected by this method call.
809 *
810 * @param millisToAdd the milliseconds to add, positive or negative
811 * @return an {@code Instant} based on this instant with the specified milliseconds added, not null
812 * @throws DateTimeException if the result exceeds the maximum or minimum instant
813 * @throws ArithmeticException if numeric overflow occurs
814 */
815 public Instant plusMillis(long millisToAdd) {
816 return plus(millisToAdd / 1000, (millisToAdd % 1000) * 1000_000);
817 }
818
819 /**
820 * Returns a copy of this instant with the specified duration in nanoseconds added.
821 * <p>
822 * This instance is immutable and unaffected by this method call.
823 *
824 * @param nanosToAdd the nanoseconds to add, positive or negative
825 * @return an {@code Instant} based on this instant with the specified nanoseconds added, not null
826 * @throws DateTimeException if the result exceeds the maximum or minimum instant
827 * @throws ArithmeticException if numeric overflow occurs
828 */
829 public Instant plusNanos(long nanosToAdd) {
830 return plus(0, nanosToAdd);
831 }
832
833 /**
834 * Returns a copy of this instant with the specified duration added.
835 * <p>
836 * This instance is immutable and unaffected by this method call.
837 *
838 * @param secondsToAdd the seconds to add, positive or negative
839 * @param nanosToAdd the nanos to add, positive or negative
840 * @return an {@code Instant} based on this instant with the specified seconds added, not null
841 * @throws DateTimeException if the result exceeds the maximum or minimum instant
842 * @throws ArithmeticException if numeric overflow occurs
843 */
844 private Instant plus(long secondsToAdd, long nanosToAdd) {
845 if ((secondsToAdd | nanosToAdd) == 0) {
846 return this;
847 }
848 long epochSec = Math.addExact(seconds, secondsToAdd);
849 epochSec = Math.addExact(epochSec, nanosToAdd / NANOS_PER_SECOND);
850 nanosToAdd = nanosToAdd % NANOS_PER_SECOND;
851 long nanoAdjustment = nanos + nanosToAdd; // safe int+NANOS_PER_SECOND
852 return ofEpochSecond(epochSec, nanoAdjustment);
853 }
854
855 //-----------------------------------------------------------------------
856 /**
857 * Returns a copy of this instant with the specified amount subtracted.
858 * <p>
859 * This returns an {@code Instant}, based on this one, with the specified amount subtracted.
860 * The amount is typically {@link Duration} but may be any other type implementing
861 * the {@link TemporalAmount} interface.
862 * <p>
863 * The calculation is delegated to the amount object by calling
864 * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
865 * to implement the subtraction in any way it wishes, however it typically
866 * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
867 * of the amount implementation to determine if it can be successfully subtracted.
868 * <p>
869 * This instance is immutable and unaffected by this method call.
870 *
871 * @param amountToSubtract the amount to subtract, not null
872 * @return an {@code Instant} based on this instant with the subtraction made, not null
873 * @throws DateTimeException if the subtraction cannot be made
874 * @throws ArithmeticException if numeric overflow occurs
875 */
876 @Override
877 public Instant minus(TemporalAmount amountToSubtract) {
878 return (Instant) amountToSubtract.subtractFrom(this);
879 }
880
881 /**
882 * Returns a copy of this instant with the specified amount subtracted.
883 * <p>
884 * This returns a {@code Instant}, based on this one, with the amount
885 * in terms of the unit subtracted. If it is not possible to subtract the amount,
886 * because the unit is not supported or for some other reason, an exception is thrown.
887 * <p>
888 * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
889 * See that method for a full description of how addition, and thus subtraction, works.
890 * <p>
891 * This instance is immutable and unaffected by this method call.
892 *
893 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
894 * @param unit the unit of the amount to subtract, not null
895 * @return an {@code Instant} based on this instant with the specified amount subtracted, not null
896 * @throws DateTimeException if the subtraction cannot be made
897 * @throws ArithmeticException if numeric overflow occurs
898 */
899 @Override
900 public Instant minus(long amountToSubtract, TemporalUnit unit) {
901 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
902 }
903
904 //-----------------------------------------------------------------------
905 /**
906 * Returns a copy of this instant with the specified duration in seconds subtracted.
907 * <p>
908 * This instance is immutable and unaffected by this method call.
909 *
910 * @param secondsToSubtract the seconds to subtract, positive or negative
911 * @return an {@code Instant} based on this instant with the specified seconds subtracted, not null
912 * @throws DateTimeException if the result exceeds the maximum or minimum instant
913 * @throws ArithmeticException if numeric overflow occurs
914 */
915 public Instant minusSeconds(long secondsToSubtract) {
916 if (secondsToSubtract == Long.MIN_VALUE) {
917 return plusSeconds(Long.MAX_VALUE).plusSeconds(1);
918 }
919 return plusSeconds(-secondsToSubtract);
920 }
921
922 /**
923 * Returns a copy of this instant with the specified duration in milliseconds subtracted.
924 * <p>
925 * This instance is immutable and unaffected by this method call.
926 *
927 * @param millisToSubtract the milliseconds to subtract, positive or negative
928 * @return an {@code Instant} based on this instant with the specified milliseconds subtracted, not null
929 * @throws DateTimeException if the result exceeds the maximum or minimum instant
930 * @throws ArithmeticException if numeric overflow occurs
931 */
932 public Instant minusMillis(long millisToSubtract) {
933 if (millisToSubtract == Long.MIN_VALUE) {
934 return plusMillis(Long.MAX_VALUE).plusMillis(1);
935 }
936 return plusMillis(-millisToSubtract);
937 }
938
939 /**
940 * Returns a copy of this instant with the specified duration in nanoseconds subtracted.
941 * <p>
942 * This instance is immutable and unaffected by this method call.
943 *
944 * @param nanosToSubtract the nanoseconds to subtract, positive or negative
945 * @return an {@code Instant} based on this instant with the specified nanoseconds subtracted, not null
946 * @throws DateTimeException if the result exceeds the maximum or minimum instant
947 * @throws ArithmeticException if numeric overflow occurs
948 */
949 public Instant minusNanos(long nanosToSubtract) {
950 if (nanosToSubtract == Long.MIN_VALUE) {
951 return plusNanos(Long.MAX_VALUE).plusNanos(1);
952 }
953 return plusNanos(-nanosToSubtract);
954 }
955
956 //-------------------------------------------------------------------------
957 /**
958 * Queries this instant using the specified query.
959 * <p>
960 * This queries this instant using the specified query strategy object.
961 * The {@code TemporalQuery} object defines the logic to be used to
962 * obtain the result. Read the documentation of the query to understand
963 * what the result of this method will be.
964 * <p>
965 * The result of this method is obtained by invoking the
966 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
967 * specified query passing {@code this} as the argument.
968 *
969 * @param <R> the type of the result
970 * @param query the query to invoke, not null
971 * @return the query result, null may be returned (defined by the query)
972 * @throws DateTimeException if unable to query (defined by the query)
973 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
974 */
975 @SuppressWarnings("unchecked")
976 @Override
977 public <R> R query(TemporalQuery<R> query) {
978 if (query == Queries.precision()) {
979 return (R) NANOS;
980 }
981 // inline TemporalAccessor.super.query(query) as an optimization
982 if (query == Queries.chronology() || query == Queries.zoneId() || query == Queries.zone() || query == Queries.offset()) {
983 return null;
984 }
985 return query.queryFrom(this);
986 }
987
988 /**
989 * Adjusts the specified temporal object to have this instant.
990 * <p>
991 * This returns a temporal object of the same observable type as the input
992 * with the instant changed to be the same as this.
993 * <p>
994 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
995 * twice, passing {@link ChronoField#INSTANT_SECONDS} and
996 * {@link ChronoField#NANO_OF_SECOND} as the fields.
997 * <p>
998 * In most cases, it is clearer to reverse the calling pattern by using
999 * {@link Temporal#with(TemporalAdjuster)}:
1000 * <pre>
1001 * // these two lines are equivalent, but the second approach is recommended
1002 * temporal = thisInstant.adjustInto(temporal);
1003 * temporal = temporal.with(thisInstant);
1004 * </pre>
1005 * <p>
1006 * This instance is immutable and unaffected by this method call.
1007 *
1008 * @param temporal the target object to be adjusted, not null
1009 * @return the adjusted object, not null
1010 * @throws DateTimeException if unable to make the adjustment
1011 * @throws ArithmeticException if numeric overflow occurs
1012 */
1013 @Override
1014 public Temporal adjustInto(Temporal temporal) {
1015 return temporal.with(INSTANT_SECONDS, seconds).with(NANO_OF_SECOND, nanos);
1016 }
1017
1018 /**
1019 * Calculates the period between this instant and another instant in
1020 * terms of the specified unit.
1021 * <p>
1022 * This calculates the period between two instants in terms of a single unit.
1023 * The start and end points are {@code this} and the specified instant.
1024 * The result will be negative if the end is before the start.
1025 * The calculation returns a whole number, representing the number of
1026 * complete units between the two instants.
1027 * The {@code Temporal} passed to this method must be an {@code Instant}.
1028 * For example, the period in days between two dates can be calculated
1029 * using {@code startInstant.periodUntil(endInstant, SECONDS)}.
1030 * <p>
1031 * This method operates in association with {@link TemporalUnit#between}.
1032 * The result of this method is a {@code long} representing the amount of
1033 * the specified unit. By contrast, the result of {@code between} is an
1034 * object that can be used directly in addition/subtraction:
1035 * <pre>
1036 * long period = start.periodUntil(end, SECONDS); // this method
1037 * dateTime.plus(SECONDS.between(start, end)); // use in plus/minus
1038 * </pre>
1039 * <p>
1040 * The calculation is implemented in this method for {@link ChronoUnit}.
1041 * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
1042 * {@code MINUTES}, {@code HOURS}, {@code HALF_DAYS} and {@code DAYS}
1043 * are supported. Other {@code ChronoUnit} values will throw an exception.
1044 * <p>
1045 * If the unit is not a {@code ChronoUnit}, then the result of this method
1046 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
1047 * passing {@code this} as the first argument and the input temporal as
1048 * the second argument.
1049 * <p>
1050 * This instance is immutable and unaffected by this method call.
1051 *
1052 * @param endInstant the end date, which must be a {@code LocalDate}, not null
1053 * @param unit the unit to measure the period in, not null
1054 * @return the amount of the period between this date and the end date
1055 * @throws DateTimeException if the period cannot be calculated
1056 * @throws ArithmeticException if numeric overflow occurs
1057 */
1058 @Override
1059 public long periodUntil(Temporal endInstant, TemporalUnit unit) {
1060 if (endInstant instanceof Instant == false) {
1061 Objects.requireNonNull(endInstant, "endInstant");
1062 throw new DateTimeException("Unable to calculate period between objects of two different types");
1063 }
1064 Instant end = (Instant) endInstant;
1065 if (unit instanceof ChronoUnit) {
1066 ChronoUnit f = (ChronoUnit) unit;
1067 switch (f) {
1068 case NANOS: return nanosUntil(end);
1069 case MICROS: return nanosUntil(end) / 1000;
1070 case MILLIS: return Math.subtractExact(end.toEpochMilli(), toEpochMilli());
1071 case SECONDS: return secondsUntil(end);
1072 case MINUTES: return secondsUntil(end) / SECONDS_PER_MINUTE;
1073 case HOURS: return secondsUntil(end) / SECONDS_PER_HOUR;
1074 case HALF_DAYS: return secondsUntil(end) / (12 * SECONDS_PER_HOUR);
1075 case DAYS: return secondsUntil(end) / (SECONDS_PER_DAY);
1076 }
1077 throw new DateTimeException("Unsupported unit: " + unit.getName());
1078 }
1079 return unit.between(this, endInstant);
1080 }
1081
1082 private long nanosUntil(Instant end) {
1083 long secs = Math.multiplyExact(secondsUntil(end), NANOS_PER_SECOND);
1084 return Math.addExact(secs, end.nanos - nanos);
1085 }
1086
1087 private long secondsUntil(Instant end) {
1088 return Math.subtractExact(end.seconds, seconds);
1089 }
1090
1091 //-----------------------------------------------------------------------
1092 /**
1093 * Combines this instant with an offset to create an {@code OffsetDateTime}.
1094 * <p>
1095 * This returns an {@code OffsetDateTime} formed from this instant at the
1096 * specified offset from UTC/Greenwich. An exception will be thrown if the
1097 * instant is too large to fit into an offset date-time.
1098 * <p>
1099 * This method is equivalent to
1100 * {@link OffsetDateTime#ofInstant(Instant, ZoneId) OffsetDateTime.ofInstant(this, offset)}.
1101 *
1102 * @param offset the offset to combine with, not null
1103 * @return the offset date-time formed from this instant and the specified offset, not null
1104 * @throws DateTimeException if the result exceeds the supported range
1105 */
1106 public OffsetDateTime atOffset(ZoneOffset offset) {
1107 return OffsetDateTime.ofInstant(this, offset);
1108 }
1109
1110 /**
1111 * Combines this instant with a time-zone to create a {@code ZonedDateTime}.
1112 * <p>
1113 * This returns an {@code ZonedDateTime} formed from this instant at the
1114 * specified time-zone. An exception will be thrown if the instant is too
1115 * large to fit into a zoned date-time.
1116 * <p>
1117 * This method is equivalent to
1118 * {@link ZonedDateTime#ofInstant(Instant, ZoneId) ZonedDateTime.ofInstant(this, zone)}.
1119 *
1120 * @param zone the zone to combine with, not null
1121 * @return the zoned date-time formed from this instant and the specified zone, not null
1122 * @throws DateTimeException if the result exceeds the supported range
1123 */
1124 public ZonedDateTime atZone(ZoneId zone) {
1125 return ZonedDateTime.ofInstant(this, zone);
1126 }
1127
1128 //-----------------------------------------------------------------------
1129 /**
1130 * Converts this instant to the number of milliseconds from the epoch
1131 * of 1970-01-01T00:00:00Z.
1132 * <p>
1133 * If this instant represents a point on the time-line too far in the future
1134 * or past to fit in a {@code long} milliseconds, then an exception is thrown.
1135 * <p>
1136 * If this instant has greater than millisecond precision, then the conversion
1137 * will drop any excess precision information as though the amount in nanoseconds
1138 * was subject to integer division by one million.
1139 *
1140 * @return the number of milliseconds since the epoch of 1970-01-01T00:00:00Z
1141 * @throws ArithmeticException if numeric overflow occurs
1142 */
1143 public long toEpochMilli() {
1144 long millis = Math.multiplyExact(seconds, 1000);
1145 return millis + nanos / 1000_000;
1146 }
1147
1148 //-----------------------------------------------------------------------
1149 /**
1150 * Compares this instant to the specified instant.
1151 * <p>
1152 * The comparison is based on the time-line position of the instants.
1153 * It is "consistent with equals", as defined by {@link Comparable}.
1154 *
1155 * @param otherInstant the other instant to compare to, not null
1156 * @return the comparator value, negative if less, positive if greater
1157 * @throws NullPointerException if otherInstant is null
1158 */
1159 @Override
1160 public int compareTo(Instant otherInstant) {
1161 int cmp = Long.compare(seconds, otherInstant.seconds);
1162 if (cmp != 0) {
1163 return cmp;
1164 }
1165 return nanos - otherInstant.nanos;
1166 }
1167
1168 /**
1169 * Checks if this instant is after the specified instant.
1170 * <p>
1171 * The comparison is based on the time-line position of the instants.
1172 *
1173 * @param otherInstant the other instant to compare to, not null
1174 * @return true if this instant is after the specified instant
1175 * @throws NullPointerException if otherInstant is null
1176 */
1177 public boolean isAfter(Instant otherInstant) {
1178 return compareTo(otherInstant) > 0;
1179 }
1180
1181 /**
1182 * Checks if this instant is before the specified instant.
1183 * <p>
1184 * The comparison is based on the time-line position of the instants.
1185 *
1186 * @param otherInstant the other instant to compare to, not null
1187 * @return true if this instant is before the specified instant
1188 * @throws NullPointerException if otherInstant is null
1189 */
1190 public boolean isBefore(Instant otherInstant) {
1191 return compareTo(otherInstant) < 0;
1192 }
1193
1194 //-----------------------------------------------------------------------
1195 /**
1196 * Checks if this instant is equal to the specified instant.
1197 * <p>
1198 * The comparison is based on the time-line position of the instants.
1199 *
1200 * @param otherInstant the other instant, null returns false
1201 * @return true if the other instant is equal to this one
1202 */
1203 @Override
1204 public boolean equals(Object otherInstant) {
1205 if (this == otherInstant) {
1206 return true;
1207 }
1208 if (otherInstant instanceof Instant) {
1209 Instant other = (Instant) otherInstant;
1210 return this.seconds == other.seconds &&
1211 this.nanos == other.nanos;
1212 }
1213 return false;
1214 }
1215
1216 /**
1217 * Returns a hash code for this instant.
1218 *
1219 * @return a suitable hash code
1220 */
1221 @Override
1222 public int hashCode() {
1223 return ((int) (seconds ^ (seconds >>> 32))) + 51 * nanos;
1224 }
1225
1226 //-----------------------------------------------------------------------
1227 /**
1228 * A string representation of this instant using ISO-8601 representation.
1229 * <p>
1230 * The format used is the same as {@link DateTimeFormatter#ISO_INSTANT}.
1231 *
1232 * @return an ISO-8601 representation of this instant, not null
1233 */
1234 @Override
1235 public String toString() {
1236 return DateTimeFormatter.ISO_INSTANT.format(this);
1237 }
1238
1239 // -----------------------------------------------------------------------
1240 /**
1241 * Writes the object using a
1242 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1243 * <pre>
1244 * out.writeByte(2); // identifies this as an Instant
1245 * out.writeLong(seconds);
1246 * out.writeInt(nanos);
1247 * </pre>
1248 *
1249 * @return the instance of {@code Ser}, not null
1250 */
1251 private Object writeReplace() {
1252 return new Ser(Ser.INSTANT_TYPE, this);
1253 }
1254
1255 /**
1256 * Defend against malicious streams.
1257 * @return never
1258 * @throws InvalidObjectException always
1259 */
1260 private Object readResolve() throws ObjectStreamException {
1261 throw new InvalidObjectException("Deserialization via serialization delegate");
1262 }
1263
1264 void writeExternal(DataOutput out) throws IOException {
1265 out.writeLong(seconds);
1266 out.writeInt(nanos);
1267 }
1268
1269 static Instant readExternal(DataInput in) throws IOException {
1270 long seconds = in.readLong();
1271 int nanos = in.readInt();
1272 return Instant.ofEpochSecond(seconds, nanos);
1273 }
1274
1275 }