1 /*
2 * Copyright (c) 2012, 2018, 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.DAYS;
73 import static java.time.temporal.ChronoUnit.NANOS;
74
75 import java.io.DataInput;
76 import java.io.DataOutput;
77 import java.io.IOException;
78 import java.io.InvalidObjectException;
79 import java.io.ObjectInputStream;
80 import java.io.Serializable;
81 import java.time.format.DateTimeFormatter;
82 import java.time.format.DateTimeParseException;
83 import java.time.temporal.ChronoField;
84 import java.time.temporal.ChronoUnit;
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.TemporalQueries;
91 import java.time.temporal.TemporalQuery;
92 import java.time.temporal.TemporalUnit;
93 import java.time.temporal.UnsupportedTemporalTypeException;
94 import java.time.temporal.ValueRange;
95 import java.util.Objects;
96
97 /**
98 * An instantaneous point on the time-line.
99 * <p>
100 * This class models a single instantaneous point on the time-line.
101 * This might be used to record event time-stamps in the application.
102 * <p>
103 * The range of an instant requires the storage of a number larger than a {@code long}.
104 * To achieve this, the class stores a {@code long} representing epoch-seconds and an
105 * {@code int} representing nanosecond-of-second, which will always be between 0 and 999,999,999.
106 * The epoch-seconds are measured from the standard Java epoch of {@code 1970-01-01T00:00:00Z}
107 * where instants after the epoch have positive values, and earlier instants have negative values.
108 * For both the epoch-second and nanosecond parts, a larger value is always later on the time-line
109 * than a smaller value.
110 *
111 * <h3>Time-scale</h3>
112 * <p>
113 * The length of the solar day is the standard way that humans measure time.
114 * This has traditionally been subdivided into 24 hours of 60 minutes of 60 seconds,
115 * forming a 86400 second day.
116 * <p>
117 * Modern timekeeping is based on atomic clocks which precisely define an SI second
118 * relative to the transitions of a Caesium atom. The length of an SI second was defined
119 * to be very close to the 86400th fraction of a day.
120 * <p>
121 * Unfortunately, as the Earth rotates the length of the day varies.
122 * In addition, over time the average length of the day is getting longer as the Earth slows.
123 * As a result, the length of a solar day in 2012 is slightly longer than 86400 SI seconds.
124 * The actual length of any given day and the amount by which the Earth is slowing
125 * are not predictable and can only be determined by measurement.
126 * The UT1 time-scale captures the accurate length of day, but is only available some
127 * time after the day has completed.
128 * <p>
129 * The UTC time-scale is a standard approach to bundle up all the additional fractions
130 * of a second from UT1 into whole seconds, known as <i>leap-seconds</i>.
131 * A leap-second may be added or removed depending on the Earth's rotational changes.
132 * As such, UTC permits a day to have 86399 SI seconds or 86401 SI seconds where
133 * necessary in order to keep the day aligned with the Sun.
134 * <p>
135 * The modern UTC time-scale was introduced in 1972, introducing the concept of whole leap-seconds.
136 * Between 1958 and 1972, the definition of UTC was complex, with minor sub-second leaps and
137 * alterations to the length of the notional second. As of 2012, discussions are underway
138 * to change the definition of UTC again, with the potential to remove leap seconds or
139 * introduce other changes.
140 * <p>
141 * Given the complexity of accurate timekeeping described above, this Java API defines
142 * its own time-scale, the <i>Java Time-Scale</i>.
143 * <p>
144 * The Java Time-Scale divides each calendar day into exactly 86400
145 * subdivisions, known as seconds. These seconds may differ from the
146 * SI second. It closely matches the de facto international civil time
147 * scale, the definition of which changes from time to time.
148 * <p>
149 * The Java Time-Scale has slightly different definitions for different
150 * segments of the time-line, each based on the consensus international
151 * time scale that is used as the basis for civil time. Whenever the
152 * internationally-agreed time scale is modified or replaced, a new
153 * segment of the Java Time-Scale must be defined for it. Each segment
154 * must meet these requirements:
155 * <ul>
156 * <li>the Java Time-Scale shall closely match the underlying international
157 * civil time scale;</li>
158 * <li>the Java Time-Scale shall exactly match the international civil
159 * time scale at noon each day;</li>
160 * <li>the Java Time-Scale shall have a precisely-defined relationship to
161 * the international civil time scale.</li>
162 * </ul>
163 * There are currently, as of 2013, two segments in the Java time-scale.
164 * <p>
165 * For the segment from 1972-11-03 (exact boundary discussed below) until
166 * further notice, the consensus international time scale is UTC (with
167 * leap seconds). In this segment, the Java Time-Scale is identical to
168 * <a href="http://www.cl.cam.ac.uk/~mgk25/time/utc-sls/">UTC-SLS</a>.
169 * This is identical to UTC on days that do not have a leap second.
170 * On days that do have a leap second, the leap second is spread equally
171 * over the last 1000 seconds of the day, maintaining the appearance of
172 * exactly 86400 seconds per day.
173 * <p>
174 * For the segment prior to 1972-11-03, extending back arbitrarily far,
175 * the consensus international time scale is defined to be UT1, applied
176 * proleptically, which is equivalent to the (mean) solar time on the
177 * prime meridian (Greenwich). In this segment, the Java Time-Scale is
178 * identical to the consensus international time scale. The exact
179 * boundary between the two segments is the instant where UT1 = UTC
180 * between 1972-11-03T00:00 and 1972-11-04T12:00.
181 * <p>
182 * Implementations of the Java time-scale using the JSR-310 API are not
183 * required to provide any clock that is sub-second accurate, or that
184 * progresses monotonically or smoothly. Implementations are therefore
185 * not required to actually perform the UTC-SLS slew or to otherwise be
186 * aware of leap seconds. JSR-310 does, however, require that
187 * implementations must document the approach they use when defining a
188 * clock representing the current instant.
189 * See {@link Clock} for details on the available clocks.
190 * <p>
191 * The Java time-scale is used for all date-time classes.
192 * This includes {@code Instant}, {@code LocalDate}, {@code LocalTime}, {@code OffsetDateTime},
193 * {@code ZonedDateTime} and {@code Duration}.
194 *
195 * <p>
196 * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
197 * class; use of identity-sensitive operations (including reference equality
198 * ({@code ==}), identity hash code, or synchronization) on instances of
199 * {@code Instant} may have unpredictable results and should be avoided.
200 * The {@code equals} method should be used for comparisons.
201 *
202 * @implSpec
203 * This class is immutable and thread-safe.
204 *
205 * @since 1.8
206 */
207 public final class Instant
208 implements Temporal, TemporalAdjuster, Comparable<Instant>, Serializable {
209
210 /**
211 * Constant for the 1970-01-01T00:00:00Z epoch instant.
212 */
213 public static final Instant EPOCH = new Instant(0, 0);
214 /**
215 * The minimum supported epoch second.
216 */
217 private static final long MIN_SECOND = -31557014167219200L;
218 /**
219 * The maximum supported epoch second.
220 */
221 private static final long MAX_SECOND = 31556889864403199L;
222 /**
223 * The minimum supported {@code Instant}, '-1000000000-01-01T00:00Z'.
224 * This could be used by an application as a "far past" instant.
225 * <p>
226 * This is one year earlier than the minimum {@code LocalDateTime}.
227 * This provides sufficient values to handle the range of {@code ZoneOffset}
228 * which affect the instant in addition to the local date-time.
229 * The value is also chosen such that the value of the year fits in
230 * an {@code int}.
231 */
232 public static final Instant MIN = Instant.ofEpochSecond(MIN_SECOND, 0);
233 /**
234 * The maximum supported {@code Instant}, '1000000000-12-31T23:59:59.999999999Z'.
235 * This could be used by an application as a "far future" instant.
236 * <p>
237 * This is one year later than the maximum {@code LocalDateTime}.
238 * This provides sufficient values to handle the range of {@code ZoneOffset}
239 * which affect the instant in addition to the local date-time.
240 * The value is also chosen such that the value of the year fits in
241 * an {@code int}.
242 */
243 public static final Instant MAX = Instant.ofEpochSecond(MAX_SECOND, 999_999_999);
244
245 /**
246 * Serialization version.
247 */
248 private static final long serialVersionUID = -665713676816604388L;
249
250 /**
251 * The number of seconds from the epoch of 1970-01-01T00:00:00Z.
252 */
253 private final long seconds;
254 /**
255 * The number of nanoseconds, later along the time-line, from the seconds field.
256 * This is always positive, and never exceeds 999,999,999.
257 */
258 private final int nanos;
259
260 //-----------------------------------------------------------------------
261 /**
262 * Obtains the current instant from the system clock.
263 * <p>
264 * This will query the {@link Clock#systemUTC() system UTC clock} to
265 * obtain the current instant.
266 * <p>
267 * Using this method will prevent the ability to use an alternate time-source for
268 * testing because the clock is effectively hard-coded.
269 *
270 * @return the current instant using the system clock, not null
271 */
272 public static Instant now() {
273 return Clock.systemUTC().instant();
274 }
275
276 /**
277 * Obtains the current instant from the specified clock.
278 * <p>
279 * This will query the specified clock to obtain the current time.
280 * <p>
281 * Using this method allows the use of an alternate clock for testing.
282 * The alternate clock may be introduced using {@link Clock dependency injection}.
283 *
284 * @param clock the clock to use, not null
285 * @return the current instant, not null
286 */
287 public static Instant now(Clock clock) {
288 Objects.requireNonNull(clock, "clock");
289 return clock.instant();
290 }
291
292 //-----------------------------------------------------------------------
293 /**
294 * Obtains an instance of {@code Instant} using seconds from the
295 * epoch of 1970-01-01T00:00:00Z.
296 * <p>
297 * The nanosecond field is set to zero.
298 *
299 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
300 * @return an instant, not null
301 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
302 */
303 public static Instant ofEpochSecond(long epochSecond) {
304 return create(epochSecond, 0);
305 }
306
307 /**
308 * Obtains an instance of {@code Instant} using seconds from the
309 * epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.
310 * <p>
311 * This method allows an arbitrary number of nanoseconds to be passed in.
312 * The factory will alter the values of the second and nanosecond in order
313 * to ensure that the stored nanosecond is in the range 0 to 999,999,999.
314 * For example, the following will result in exactly the same instant:
315 * <pre>
316 * Instant.ofEpochSecond(3, 1);
317 * Instant.ofEpochSecond(4, -999_999_999);
318 * Instant.ofEpochSecond(2, 1000_000_001);
319 * </pre>
320 *
321 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
322 * @param nanoAdjustment the nanosecond adjustment to the number of seconds, positive or negative
323 * @return an instant, not null
324 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
325 * @throws ArithmeticException if numeric overflow occurs
326 */
327 public static Instant ofEpochSecond(long epochSecond, long nanoAdjustment) {
328 long secs = Math.addExact(epochSecond, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND));
329 int nos = (int)Math.floorMod(nanoAdjustment, NANOS_PER_SECOND);
330 return create(secs, nos);
331 }
332
333 /**
334 * Obtains an instance of {@code Instant} using milliseconds from the
335 * epoch of 1970-01-01T00:00:00Z.
336 * <p>
337 * The seconds and nanoseconds are extracted from the specified milliseconds.
338 *
339 * @param epochMilli the number of milliseconds from 1970-01-01T00:00:00Z
340 * @return an instant, not null
341 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
342 */
343 public static Instant ofEpochMilli(long epochMilli) {
344 long secs = Math.floorDiv(epochMilli, 1000);
345 int mos = Math.floorMod(epochMilli, 1000);
346 return create(secs, mos * 1000_000);
347 }
348
349 //-----------------------------------------------------------------------
350 /**
351 * Obtains an instance of {@code Instant} from a temporal object.
352 * <p>
353 * This obtains an instant based on the specified temporal.
354 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
355 * which this factory converts to an instance of {@code Instant}.
356 * <p>
357 * The conversion extracts the {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS}
358 * and {@link ChronoField#NANO_OF_SECOND NANO_OF_SECOND} fields.
359 * <p>
360 * This method matches the signature of the functional interface {@link TemporalQuery}
361 * allowing it to be used as a query via method reference, {@code Instant::from}.
362 *
363 * @param temporal the temporal object to convert, not null
364 * @return the instant, not null
365 * @throws DateTimeException if unable to convert to an {@code Instant}
366 */
367 public static Instant from(TemporalAccessor temporal) {
368 if (temporal instanceof Instant) {
369 return (Instant) temporal;
370 }
371 Objects.requireNonNull(temporal, "temporal");
372 try {
373 long instantSecs = temporal.getLong(INSTANT_SECONDS);
374 int nanoOfSecond = temporal.get(NANO_OF_SECOND);
375 return Instant.ofEpochSecond(instantSecs, nanoOfSecond);
376 } catch (DateTimeException ex) {
377 throw new DateTimeException("Unable to obtain Instant from TemporalAccessor: " +
378 temporal + " of type " + temporal.getClass().getName(), ex);
379 }
380 }
381
382 //-----------------------------------------------------------------------
383 /**
384 * Obtains an instance of {@code Instant} from a text string such as
385 * {@code 2007-12-03T10:15:30.00Z}.
386 * <p>
387 * The string must represent a valid instant in UTC and is parsed using
388 * {@link DateTimeFormatter#ISO_INSTANT}.
389 *
390 * @param text the text to parse, not null
391 * @return the parsed instant, not null
392 * @throws DateTimeParseException if the text cannot be parsed
393 */
394 public static Instant parse(final CharSequence text) {
395 return DateTimeFormatter.ISO_INSTANT.parse(text, Instant::from);
396 }
397
398 //-----------------------------------------------------------------------
399 /**
400 * Obtains an instance of {@code Instant} using seconds and nanoseconds.
401 *
402 * @param seconds the length of the duration in seconds
403 * @param nanoOfSecond the nano-of-second, from 0 to 999,999,999
404 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
405 */
406 private static Instant create(long seconds, int nanoOfSecond) {
407 if ((seconds | nanoOfSecond) == 0) {
408 return EPOCH;
409 }
410 if (seconds < MIN_SECOND || seconds > MAX_SECOND) {
411 throw new DateTimeException("Instant exceeds minimum or maximum instant");
412 }
413 return new Instant(seconds, nanoOfSecond);
414 }
415
416 /**
417 * Constructs an instance of {@code Instant} using seconds from the epoch of
418 * 1970-01-01T00:00:00Z and nanosecond fraction of second.
419 *
420 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
421 * @param nanos the nanoseconds within the second, must be positive
422 */
423 private Instant(long epochSecond, int nanos) {
424 super();
425 this.seconds = epochSecond;
426 this.nanos = nanos;
427 }
428
429 //-----------------------------------------------------------------------
430 /**
431 * Checks if the specified field is supported.
432 * <p>
433 * This checks if this instant can be queried for the specified field.
434 * If false, then calling the {@link #range(TemporalField) range},
435 * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
436 * methods will throw an exception.
437 * <p>
438 * If the field is a {@link ChronoField} then the query is implemented here.
439 * The supported fields are:
440 * <ul>
441 * <li>{@code NANO_OF_SECOND}
442 * <li>{@code MICRO_OF_SECOND}
443 * <li>{@code MILLI_OF_SECOND}
444 * <li>{@code INSTANT_SECONDS}
445 * </ul>
446 * All other {@code ChronoField} instances will return false.
447 * <p>
448 * If the field is not a {@code ChronoField}, then the result of this method
449 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
450 * passing {@code this} as the argument.
451 * Whether the field is supported is determined by the field.
452 *
453 * @param field the field to check, null returns false
454 * @return true if the field is supported on this instant, false if not
455 */
456 @Override
457 public boolean isSupported(TemporalField field) {
458 if (field instanceof ChronoField) {
459 return field == INSTANT_SECONDS || field == NANO_OF_SECOND || field == MICRO_OF_SECOND || field == MILLI_OF_SECOND;
460 }
461 return field != null && field.isSupportedBy(this);
462 }
463
464 /**
465 * Checks if the specified unit is supported.
466 * <p>
467 * This checks if the specified unit can be added to, or subtracted from, this date-time.
468 * If false, then calling the {@link #plus(long, TemporalUnit)} and
469 * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
470 * <p>
471 * If the unit is a {@link ChronoUnit} then the query is implemented here.
472 * The supported units are:
473 * <ul>
474 * <li>{@code NANOS}
475 * <li>{@code MICROS}
476 * <li>{@code MILLIS}
477 * <li>{@code SECONDS}
478 * <li>{@code MINUTES}
479 * <li>{@code HOURS}
480 * <li>{@code HALF_DAYS}
481 * <li>{@code DAYS}
482 * </ul>
483 * All other {@code ChronoUnit} instances will return false.
484 * <p>
485 * If the unit is not a {@code ChronoUnit}, then the result of this method
486 * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
487 * passing {@code this} as the argument.
488 * Whether the unit is supported is determined by the unit.
489 *
490 * @param unit the unit to check, null returns false
491 * @return true if the unit can be added/subtracted, false if not
492 */
493 @Override
494 public boolean isSupported(TemporalUnit unit) {
495 if (unit instanceof ChronoUnit) {
496 return unit.isTimeBased() || unit == DAYS;
497 }
498 return unit != null && unit.isSupportedBy(this);
499 }
500
501 //-----------------------------------------------------------------------
502 /**
503 * Gets the range of valid values for the specified field.
504 * <p>
505 * The range object expresses the minimum and maximum valid values for a field.
506 * This instant is used to enhance the accuracy of the returned range.
507 * If it is not possible to return the range, because the field is not supported
508 * or for some other reason, an exception is thrown.
509 * <p>
510 * If the field is a {@link ChronoField} then the query is implemented here.
511 * The {@link #isSupported(TemporalField) supported fields} will return
512 * appropriate range instances.
513 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
514 * <p>
515 * If the field is not a {@code ChronoField}, then the result of this method
516 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
517 * passing {@code this} as the argument.
518 * Whether the range can be obtained is determined by the field.
519 *
520 * @param field the field to query the range for, not null
521 * @return the range of valid values for the field, not null
522 * @throws DateTimeException if the range for the field cannot be obtained
523 * @throws UnsupportedTemporalTypeException if the field is not supported
524 */
525 @Override // override for Javadoc
526 public ValueRange range(TemporalField field) {
527 return Temporal.super.range(field);
528 }
529
530 /**
531 * Gets the value of the specified field from this instant as an {@code int}.
532 * <p>
533 * This queries this instant for the value of the specified field.
534 * The returned value will always be within the valid range of values for the field.
535 * If it is not possible to return the value, because the field is not supported
536 * or for some other reason, an exception is thrown.
537 * <p>
538 * If the field is a {@link ChronoField} then the query is implemented here.
539 * The {@link #isSupported(TemporalField) supported fields} will return valid
540 * values based on this date-time, except {@code INSTANT_SECONDS} which is too
541 * large to fit in an {@code int} and throws a {@code DateTimeException}.
542 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
543 * <p>
544 * If the field is not a {@code ChronoField}, then the result of this method
545 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
546 * passing {@code this} as the argument. Whether the value can be obtained,
547 * and what the value represents, is determined by the field.
548 *
549 * @param field the field to get, not null
550 * @return the value for the field
551 * @throws DateTimeException if a value for the field cannot be obtained or
552 * the value is outside the range of valid values for the field
553 * @throws UnsupportedTemporalTypeException if the field is not supported or
554 * the range of values exceeds an {@code int}
555 * @throws ArithmeticException if numeric overflow occurs
556 */
557 @Override // override for Javadoc and performance
558 public int get(TemporalField field) {
559 if (field instanceof ChronoField) {
560 switch ((ChronoField) field) {
561 case NANO_OF_SECOND: return nanos;
562 case MICRO_OF_SECOND: return nanos / 1000;
563 case MILLI_OF_SECOND: return nanos / 1000_000;
564 }
565 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
566 }
567 return range(field).checkValidIntValue(field.getFrom(this), field);
568 }
569
570 /**
571 * Gets the value of the specified field from this instant as a {@code long}.
572 * <p>
573 * This queries this instant for the value of the specified field.
574 * If it is not possible to return the value, because the field is not supported
575 * or for some other reason, an exception is thrown.
576 * <p>
577 * If the field is a {@link ChronoField} then the query is implemented here.
578 * The {@link #isSupported(TemporalField) supported fields} will return valid
579 * values based on this date-time.
580 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
581 * <p>
582 * If the field is not a {@code ChronoField}, then the result of this method
583 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
584 * passing {@code this} as the argument. Whether the value can be obtained,
585 * and what the value represents, is determined by the field.
586 *
587 * @param field the field to get, not null
588 * @return the value for the field
589 * @throws DateTimeException if a value for the field cannot be obtained
590 * @throws UnsupportedTemporalTypeException if the field is not supported
591 * @throws ArithmeticException if numeric overflow occurs
592 */
593 @Override
594 public long getLong(TemporalField field) {
595 if (field instanceof ChronoField) {
596 switch ((ChronoField) field) {
597 case NANO_OF_SECOND: return nanos;
598 case MICRO_OF_SECOND: return nanos / 1000;
599 case MILLI_OF_SECOND: return nanos / 1000_000;
600 case INSTANT_SECONDS: return seconds;
601 }
602 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
603 }
604 return field.getFrom(this);
605 }
606
607 //-----------------------------------------------------------------------
608 /**
609 * Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.
610 * <p>
611 * The epoch second count is a simple incrementing count of seconds where
612 * second 0 is 1970-01-01T00:00:00Z.
613 * The nanosecond part is returned by {@link #getNano}.
614 *
615 * @return the seconds from the epoch of 1970-01-01T00:00:00Z
616 */
617 public long getEpochSecond() {
618 return seconds;
619 }
620
621 /**
622 * Gets the number of nanoseconds, later along the time-line, from the start
623 * of the second.
624 * <p>
625 * The nanosecond-of-second value measures the total number of nanoseconds from
626 * the second returned by {@link #getEpochSecond}.
627 *
628 * @return the nanoseconds within the second, always positive, never exceeds 999,999,999
629 */
630 public int getNano() {
631 return nanos;
632 }
633
634 //-------------------------------------------------------------------------
635 /**
636 * Returns an adjusted copy of this instant.
637 * <p>
638 * This returns an {@code Instant}, based on this one, with the instant adjusted.
639 * The adjustment takes place using the specified adjuster strategy object.
640 * Read the documentation of the adjuster to understand what adjustment will be made.
641 * <p>
642 * The result of this method is obtained by invoking the
643 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
644 * specified adjuster passing {@code this} as the argument.
645 * <p>
646 * This instance is immutable and unaffected by this method call.
647 *
648 * @param adjuster the adjuster to use, not null
649 * @return an {@code Instant} based on {@code this} with the adjustment made, not null
650 * @throws DateTimeException if the adjustment cannot be made
651 * @throws ArithmeticException if numeric overflow occurs
652 */
653 @Override
654 public Instant with(TemporalAdjuster adjuster) {
655 return (Instant) adjuster.adjustInto(this);
656 }
657
658 /**
659 * Returns a copy of this instant with the specified field set to a new value.
660 * <p>
661 * This returns an {@code Instant}, based on this one, with the value
662 * for the specified field changed.
663 * If it is not possible to set the value, because the field is not supported or for
664 * some other reason, an exception is thrown.
665 * <p>
666 * If the field is a {@link ChronoField} then the adjustment is implemented here.
667 * The supported fields behave as follows:
668 * <ul>
669 * <li>{@code NANO_OF_SECOND} -
670 * Returns an {@code Instant} with the specified nano-of-second.
671 * The epoch-second will be unchanged.
672 * <li>{@code MICRO_OF_SECOND} -
673 * Returns an {@code Instant} with the nano-of-second replaced by the specified
674 * micro-of-second multiplied by 1,000. The epoch-second will be unchanged.
675 * <li>{@code MILLI_OF_SECOND} -
676 * Returns an {@code Instant} with the nano-of-second replaced by the specified
677 * milli-of-second multiplied by 1,000,000. The epoch-second will be unchanged.
678 * <li>{@code INSTANT_SECONDS} -
679 * Returns an {@code Instant} with the specified epoch-second.
680 * The nano-of-second will be unchanged.
681 * </ul>
682 * <p>
683 * In all cases, if the new value is outside the valid range of values for the field
684 * then a {@code DateTimeException} will be thrown.
685 * <p>
686 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
687 * <p>
688 * If the field is not a {@code ChronoField}, then the result of this method
689 * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
690 * passing {@code this} as the argument. In this case, the field determines
691 * whether and how to adjust the instant.
692 * <p>
693 * This instance is immutable and unaffected by this method call.
694 *
695 * @param field the field to set in the result, not null
696 * @param newValue the new value of the field in the result
697 * @return an {@code Instant} based on {@code this} with the specified field set, not null
698 * @throws DateTimeException if the field cannot be set
699 * @throws UnsupportedTemporalTypeException if the field is not supported
700 * @throws ArithmeticException if numeric overflow occurs
701 */
702 @Override
703 public Instant with(TemporalField field, long newValue) {
704 if (field instanceof ChronoField) {
705 ChronoField f = (ChronoField) field;
706 f.checkValidValue(newValue);
707 switch (f) {
708 case MILLI_OF_SECOND: {
709 int nval = (int) newValue * 1000_000;
710 return (nval != nanos ? create(seconds, nval) : this);
711 }
712 case MICRO_OF_SECOND: {
713 int nval = (int) newValue * 1000;
714 return (nval != nanos ? create(seconds, nval) : this);
715 }
716 case NANO_OF_SECOND: return (newValue != nanos ? create(seconds, (int) newValue) : this);
717 case INSTANT_SECONDS: return (newValue != seconds ? create(newValue, nanos) : this);
718 }
719 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
720 }
721 return field.adjustInto(this, newValue);
722 }
723
724 //-----------------------------------------------------------------------
725 /**
726 * Returns a copy of this {@code Instant} truncated to the specified unit.
727 * <p>
728 * Truncating the instant returns a copy of the original with fields
729 * smaller than the specified unit set to zero.
730 * The fields are calculated on the basis of using a UTC offset as seen
731 * in {@code toString}.
732 * For example, truncating with the {@link ChronoUnit#MINUTES MINUTES} unit will
733 * round down to the nearest minute, setting the seconds and nanoseconds to zero.
734 * <p>
735 * The unit must have a {@linkplain TemporalUnit#getDuration() duration}
736 * that divides into the length of a standard day without remainder.
737 * This includes all supplied time units on {@link ChronoUnit} and
738 * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception.
739 * <p>
740 * This instance is immutable and unaffected by this method call.
741 *
742 * @param unit the unit to truncate to, not null
743 * @return an {@code Instant} based on this instant with the time truncated, not null
744 * @throws DateTimeException if the unit is invalid for truncation
745 * @throws UnsupportedTemporalTypeException if the unit is not supported
746 */
747 public Instant truncatedTo(TemporalUnit unit) {
748 if (unit == ChronoUnit.NANOS) {
749 return this;
750 }
751 Duration unitDur = unit.getDuration();
752 if (unitDur.getSeconds() > LocalTime.SECONDS_PER_DAY) {
753 throw new UnsupportedTemporalTypeException("Unit is too large to be used for truncation");
754 }
755 long dur = unitDur.toNanos();
756 if ((LocalTime.NANOS_PER_DAY % dur) != 0) {
757 throw new UnsupportedTemporalTypeException("Unit must divide into a standard day without remainder");
758 }
759 long nod = (seconds % LocalTime.SECONDS_PER_DAY) * LocalTime.NANOS_PER_SECOND + nanos;
760 long result = Math.floorDiv(nod, dur) * dur;
761 return plusNanos(result - nod);
762 }
763
764 //-----------------------------------------------------------------------
765 /**
766 * Returns a copy of this instant with the specified amount added.
767 * <p>
768 * This returns an {@code Instant}, based on this one, with the specified amount added.
769 * The amount is typically {@link Duration} but may be any other type implementing
770 * the {@link TemporalAmount} interface.
771 * <p>
772 * The calculation is delegated to the amount object by calling
773 * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
774 * to implement the addition in any way it wishes, however it typically
775 * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
776 * of the amount implementation to determine if it can be successfully added.
777 * <p>
778 * This instance is immutable and unaffected by this method call.
779 *
780 * @param amountToAdd the amount to add, not null
781 * @return an {@code Instant} based on this instant with the addition made, not null
782 * @throws DateTimeException if the addition cannot be made
783 * @throws ArithmeticException if numeric overflow occurs
784 */
785 @Override
786 public Instant plus(TemporalAmount amountToAdd) {
787 return (Instant) amountToAdd.addTo(this);
788 }
789
790 /**
791 * Returns a copy of this instant with the specified amount added.
792 * <p>
793 * This returns an {@code Instant}, based on this one, with the amount
794 * in terms of the unit added. If it is not possible to add the amount, because the
795 * unit is not supported or for some other reason, an exception is thrown.
796 * <p>
797 * If the field is a {@link ChronoUnit} then the addition is implemented here.
798 * The supported fields behave as follows:
799 * <ul>
800 * <li>{@code NANOS} -
801 * Returns an {@code Instant} with the specified number of nanoseconds added.
802 * This is equivalent to {@link #plusNanos(long)}.
803 * <li>{@code MICROS} -
804 * Returns an {@code Instant} with the specified number of microseconds added.
805 * This is equivalent to {@link #plusNanos(long)} with the amount
806 * multiplied by 1,000.
807 * <li>{@code MILLIS} -
808 * Returns an {@code Instant} with the specified number of milliseconds added.
809 * This is equivalent to {@link #plusNanos(long)} with the amount
810 * multiplied by 1,000,000.
811 * <li>{@code SECONDS} -
812 * Returns an {@code Instant} with the specified number of seconds added.
813 * This is equivalent to {@link #plusSeconds(long)}.
814 * <li>{@code MINUTES} -
815 * Returns an {@code Instant} with the specified number of minutes added.
816 * This is equivalent to {@link #plusSeconds(long)} with the amount
817 * multiplied by 60.
818 * <li>{@code HOURS} -
819 * Returns an {@code Instant} with the specified number of hours added.
820 * This is equivalent to {@link #plusSeconds(long)} with the amount
821 * multiplied by 3,600.
822 * <li>{@code HALF_DAYS} -
823 * Returns an {@code Instant} with the specified number of half-days added.
824 * This is equivalent to {@link #plusSeconds(long)} with the amount
825 * multiplied by 43,200 (12 hours).
826 * <li>{@code DAYS} -
827 * Returns an {@code Instant} with the specified number of days added.
828 * This is equivalent to {@link #plusSeconds(long)} with the amount
829 * multiplied by 86,400 (24 hours).
830 * </ul>
831 * <p>
832 * All other {@code ChronoUnit} instances will throw an {@code UnsupportedTemporalTypeException}.
833 * <p>
834 * If the field is not a {@code ChronoUnit}, then the result of this method
835 * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
836 * passing {@code this} as the argument. In this case, the unit determines
837 * whether and how to perform the addition.
838 * <p>
839 * This instance is immutable and unaffected by this method call.
840 *
841 * @param amountToAdd the amount of the unit to add to the result, may be negative
842 * @param unit the unit of the amount to add, not null
843 * @return an {@code Instant} based on this instant with the specified amount added, not null
844 * @throws DateTimeException if the addition cannot be made
845 * @throws UnsupportedTemporalTypeException if the unit is not supported
846 * @throws ArithmeticException if numeric overflow occurs
847 */
848 @Override
849 public Instant plus(long amountToAdd, TemporalUnit unit) {
850 if (unit instanceof ChronoUnit) {
851 switch ((ChronoUnit) unit) {
852 case NANOS: return plusNanos(amountToAdd);
853 case MICROS: return plus(amountToAdd / 1000_000, (amountToAdd % 1000_000) * 1000);
854 case MILLIS: return plusMillis(amountToAdd);
855 case SECONDS: return plusSeconds(amountToAdd);
856 case MINUTES: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_MINUTE));
857 case HOURS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_HOUR));
858 case HALF_DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY / 2));
859 case DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY));
860 }
861 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
862 }
863 return unit.addTo(this, amountToAdd);
864 }
865
866 //-----------------------------------------------------------------------
867 /**
868 * Returns a copy of this instant with the specified duration in seconds added.
869 * <p>
870 * This instance is immutable and unaffected by this method call.
871 *
872 * @param secondsToAdd the seconds to add, positive or negative
873 * @return an {@code Instant} based on this instant with the specified seconds added, not null
874 * @throws DateTimeException if the result exceeds the maximum or minimum instant
875 * @throws ArithmeticException if numeric overflow occurs
876 */
877 public Instant plusSeconds(long secondsToAdd) {
878 return plus(secondsToAdd, 0);
879 }
880
881 /**
882 * Returns a copy of this instant with the specified duration in milliseconds added.
883 * <p>
884 * This instance is immutable and unaffected by this method call.
885 *
886 * @param millisToAdd the milliseconds to add, positive or negative
887 * @return an {@code Instant} based on this instant with the specified milliseconds added, not null
888 * @throws DateTimeException if the result exceeds the maximum or minimum instant
889 * @throws ArithmeticException if numeric overflow occurs
890 */
891 public Instant plusMillis(long millisToAdd) {
892 return plus(millisToAdd / 1000, (millisToAdd % 1000) * 1000_000);
893 }
894
895 /**
896 * Returns a copy of this instant with the specified duration in nanoseconds added.
897 * <p>
898 * This instance is immutable and unaffected by this method call.
899 *
900 * @param nanosToAdd the nanoseconds to add, positive or negative
901 * @return an {@code Instant} based on this instant with the specified nanoseconds added, not null
902 * @throws DateTimeException if the result exceeds the maximum or minimum instant
903 * @throws ArithmeticException if numeric overflow occurs
904 */
905 public Instant plusNanos(long nanosToAdd) {
906 return plus(0, nanosToAdd);
907 }
908
909 /**
910 * Returns a copy of this instant with the specified duration added.
911 * <p>
912 * This instance is immutable and unaffected by this method call.
913 *
914 * @param secondsToAdd the seconds to add, positive or negative
915 * @param nanosToAdd the nanos to add, positive or negative
916 * @return an {@code Instant} based on this instant with the specified seconds added, not null
917 * @throws DateTimeException if the result exceeds the maximum or minimum instant
918 * @throws ArithmeticException if numeric overflow occurs
919 */
920 private Instant plus(long secondsToAdd, long nanosToAdd) {
921 if ((secondsToAdd | nanosToAdd) == 0) {
922 return this;
923 }
924 long epochSec = Math.addExact(seconds, secondsToAdd);
925 epochSec = Math.addExact(epochSec, nanosToAdd / NANOS_PER_SECOND);
926 nanosToAdd = nanosToAdd % NANOS_PER_SECOND;
927 long nanoAdjustment = nanos + nanosToAdd; // safe int+NANOS_PER_SECOND
928 return ofEpochSecond(epochSec, nanoAdjustment);
929 }
930
931 //-----------------------------------------------------------------------
932 /**
933 * Returns a copy of this instant with the specified amount subtracted.
934 * <p>
935 * This returns an {@code Instant}, based on this one, with the specified amount subtracted.
936 * The amount is typically {@link Duration} but may be any other type implementing
937 * the {@link TemporalAmount} interface.
938 * <p>
939 * The calculation is delegated to the amount object by calling
940 * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
941 * to implement the subtraction in any way it wishes, however it typically
942 * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
943 * of the amount implementation to determine if it can be successfully subtracted.
944 * <p>
945 * This instance is immutable and unaffected by this method call.
946 *
947 * @param amountToSubtract the amount to subtract, not null
948 * @return an {@code Instant} based on this instant with the subtraction made, not null
949 * @throws DateTimeException if the subtraction cannot be made
950 * @throws ArithmeticException if numeric overflow occurs
951 */
952 @Override
953 public Instant minus(TemporalAmount amountToSubtract) {
954 return (Instant) amountToSubtract.subtractFrom(this);
955 }
956
957 /**
958 * Returns a copy of this instant with the specified amount subtracted.
959 * <p>
960 * This returns an {@code Instant}, based on this one, with the amount
961 * in terms of the unit subtracted. If it is not possible to subtract the amount,
962 * because the unit is not supported or for some other reason, an exception is thrown.
963 * <p>
964 * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
965 * See that method for a full description of how addition, and thus subtraction, works.
966 * <p>
967 * This instance is immutable and unaffected by this method call.
968 *
969 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
970 * @param unit the unit of the amount to subtract, not null
971 * @return an {@code Instant} based on this instant with the specified amount subtracted, not null
972 * @throws DateTimeException if the subtraction cannot be made
973 * @throws UnsupportedTemporalTypeException if the unit is not supported
974 * @throws ArithmeticException if numeric overflow occurs
975 */
976 @Override
977 public Instant minus(long amountToSubtract, TemporalUnit unit) {
978 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
979 }
980
981 //-----------------------------------------------------------------------
982 /**
983 * Returns a copy of this instant with the specified duration in seconds subtracted.
984 * <p>
985 * This instance is immutable and unaffected by this method call.
986 *
987 * @param secondsToSubtract the seconds to subtract, positive or negative
988 * @return an {@code Instant} based on this instant with the specified seconds subtracted, not null
989 * @throws DateTimeException if the result exceeds the maximum or minimum instant
990 * @throws ArithmeticException if numeric overflow occurs
991 */
992 public Instant minusSeconds(long secondsToSubtract) {
993 if (secondsToSubtract == Long.MIN_VALUE) {
994 return plusSeconds(Long.MAX_VALUE).plusSeconds(1);
995 }
996 return plusSeconds(-secondsToSubtract);
997 }
998
999 /**
1000 * Returns a copy of this instant with the specified duration in milliseconds subtracted.
1001 * <p>
1002 * This instance is immutable and unaffected by this method call.
1003 *
1004 * @param millisToSubtract the milliseconds to subtract, positive or negative
1005 * @return an {@code Instant} based on this instant with the specified milliseconds subtracted, not null
1006 * @throws DateTimeException if the result exceeds the maximum or minimum instant
1007 * @throws ArithmeticException if numeric overflow occurs
1008 */
1009 public Instant minusMillis(long millisToSubtract) {
1010 if (millisToSubtract == Long.MIN_VALUE) {
1011 return plusMillis(Long.MAX_VALUE).plusMillis(1);
1012 }
1013 return plusMillis(-millisToSubtract);
1014 }
1015
1016 /**
1017 * Returns a copy of this instant with the specified duration in nanoseconds subtracted.
1018 * <p>
1019 * This instance is immutable and unaffected by this method call.
1020 *
1021 * @param nanosToSubtract the nanoseconds to subtract, positive or negative
1022 * @return an {@code Instant} based on this instant with the specified nanoseconds subtracted, not null
1023 * @throws DateTimeException if the result exceeds the maximum or minimum instant
1024 * @throws ArithmeticException if numeric overflow occurs
1025 */
1026 public Instant minusNanos(long nanosToSubtract) {
1027 if (nanosToSubtract == Long.MIN_VALUE) {
1028 return plusNanos(Long.MAX_VALUE).plusNanos(1);
1029 }
1030 return plusNanos(-nanosToSubtract);
1031 }
1032
1033 //-------------------------------------------------------------------------
1034 /**
1035 * Queries this instant using the specified query.
1036 * <p>
1037 * This queries this instant using the specified query strategy object.
1038 * The {@code TemporalQuery} object defines the logic to be used to
1039 * obtain the result. Read the documentation of the query to understand
1040 * what the result of this method will be.
1041 * <p>
1042 * The result of this method is obtained by invoking the
1043 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
1044 * specified query passing {@code this} as the argument.
1045 *
1046 * @param <R> the type of the result
1047 * @param query the query to invoke, not null
1048 * @return the query result, null may be returned (defined by the query)
1049 * @throws DateTimeException if unable to query (defined by the query)
1050 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
1051 */
1052 @SuppressWarnings("unchecked")
1053 @Override
1054 public <R> R query(TemporalQuery<R> query) {
1055 if (query == TemporalQueries.precision()) {
1056 return (R) NANOS;
1057 }
1058 // inline TemporalAccessor.super.query(query) as an optimization
1059 if (query == TemporalQueries.chronology() || query == TemporalQueries.zoneId() ||
1060 query == TemporalQueries.zone() || query == TemporalQueries.offset() ||
1061 query == TemporalQueries.localDate() || query == TemporalQueries.localTime()) {
1062 return null;
1063 }
1064 return query.queryFrom(this);
1065 }
1066
1067 /**
1068 * Adjusts the specified temporal object to have this instant.
1069 * <p>
1070 * This returns a temporal object of the same observable type as the input
1071 * with the instant changed to be the same as this.
1072 * <p>
1073 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
1074 * twice, passing {@link ChronoField#INSTANT_SECONDS} and
1075 * {@link ChronoField#NANO_OF_SECOND} as the fields.
1076 * <p>
1077 * In most cases, it is clearer to reverse the calling pattern by using
1078 * {@link Temporal#with(TemporalAdjuster)}:
1079 * <pre>
1080 * // these two lines are equivalent, but the second approach is recommended
1081 * temporal = thisInstant.adjustInto(temporal);
1082 * temporal = temporal.with(thisInstant);
1083 * </pre>
1084 * <p>
1085 * This instance is immutable and unaffected by this method call.
1086 *
1087 * @param temporal the target object to be adjusted, not null
1088 * @return the adjusted object, not null
1089 * @throws DateTimeException if unable to make the adjustment
1090 * @throws ArithmeticException if numeric overflow occurs
1091 */
1092 @Override
1093 public Temporal adjustInto(Temporal temporal) {
1094 return temporal.with(INSTANT_SECONDS, seconds).with(NANO_OF_SECOND, nanos);
1095 }
1096
1097 /**
1098 * Calculates the amount of time until another instant in terms of the specified unit.
1099 * <p>
1100 * This calculates the amount of time between two {@code Instant}
1101 * objects in terms of a single {@code TemporalUnit}.
1102 * The start and end points are {@code this} and the specified instant.
1103 * The result will be negative if the end is before the start.
1104 * The calculation returns a whole number, representing the number of
1105 * complete units between the two instants.
1106 * The {@code Temporal} passed to this method is converted to a
1107 * {@code Instant} using {@link #from(TemporalAccessor)}.
1108 * For example, the amount in seconds between two dates can be calculated
1109 * using {@code startInstant.until(endInstant, SECONDS)}.
1110 * <p>
1111 * There are two equivalent ways of using this method.
1112 * The first is to invoke this method.
1113 * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
1114 * <pre>
1115 * // these two lines are equivalent
1116 * amount = start.until(end, SECONDS);
1117 * amount = SECONDS.between(start, end);
1118 * </pre>
1119 * The choice should be made based on which makes the code more readable.
1120 * <p>
1121 * The calculation is implemented in this method for {@link ChronoUnit}.
1122 * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
1123 * {@code MINUTES}, {@code HOURS}, {@code HALF_DAYS} and {@code DAYS}
1124 * are supported. Other {@code ChronoUnit} values will throw an exception.
1125 * <p>
1126 * If the unit is not a {@code ChronoUnit}, then the result of this method
1127 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
1128 * passing {@code this} as the first argument and the converted input temporal
1129 * as the second argument.
1130 * <p>
1131 * This instance is immutable and unaffected by this method call.
1132 *
1133 * @param endExclusive the end date, exclusive, which is converted to an {@code Instant}, not null
1134 * @param unit the unit to measure the amount in, not null
1135 * @return the amount of time between this instant and the end instant
1136 * @throws DateTimeException if the amount cannot be calculated, or the end
1137 * temporal cannot be converted to an {@code Instant}
1138 * @throws UnsupportedTemporalTypeException if the unit is not supported
1139 * @throws ArithmeticException if numeric overflow occurs
1140 */
1141 @Override
1142 public long until(Temporal endExclusive, TemporalUnit unit) {
1143 Instant end = Instant.from(endExclusive);
1144 if (unit instanceof ChronoUnit) {
1145 ChronoUnit f = (ChronoUnit) unit;
1146 switch (f) {
1147 case NANOS: return nanosUntil(end);
1148 case MICROS: return nanosUntil(end) / 1000;
1149 case MILLIS: return Math.subtractExact(end.toEpochMilli(), toEpochMilli());
1150 case SECONDS: return secondsUntil(end);
1151 case MINUTES: return secondsUntil(end) / SECONDS_PER_MINUTE;
1152 case HOURS: return secondsUntil(end) / SECONDS_PER_HOUR;
1153 case HALF_DAYS: return secondsUntil(end) / (12 * SECONDS_PER_HOUR);
1154 case DAYS: return secondsUntil(end) / (SECONDS_PER_DAY);
1155 }
1156 throw new UnsupportedTemporalTypeException("Unsupported unit: " + unit);
1157 }
1158 return unit.between(this, end);
1159 }
1160
1161 private long nanosUntil(Instant end) {
1162 long secsDiff = Math.subtractExact(end.seconds, seconds);
1163 long totalNanos = Math.multiplyExact(secsDiff, NANOS_PER_SECOND);
1164 return Math.addExact(totalNanos, end.nanos - nanos);
1165 }
1166
1167 private long secondsUntil(Instant end) {
1168 long secsDiff = Math.subtractExact(end.seconds, seconds);
1169 long nanosDiff = end.nanos - nanos;
1170 if (secsDiff > 0 && nanosDiff < 0) {
1171 secsDiff--;
1172 } else if (secsDiff < 0 && nanosDiff > 0) {
1173 secsDiff++;
1174 }
1175 return secsDiff;
1176 }
1177
1178 //-----------------------------------------------------------------------
1179 /**
1180 * Combines this instant with an offset to create an {@code OffsetDateTime}.
1181 * <p>
1182 * This returns an {@code OffsetDateTime} formed from this instant at the
1183 * specified offset from UTC/Greenwich. An exception will be thrown if the
1184 * instant is too large to fit into an offset date-time.
1185 * <p>
1186 * This method is equivalent to
1187 * {@link OffsetDateTime#ofInstant(Instant, ZoneId) OffsetDateTime.ofInstant(this, offset)}.
1188 *
1189 * @param offset the offset to combine with, not null
1190 * @return the offset date-time formed from this instant and the specified offset, not null
1191 * @throws DateTimeException if the result exceeds the supported range
1192 */
1193 public OffsetDateTime atOffset(ZoneOffset offset) {
1194 return OffsetDateTime.ofInstant(this, offset);
1195 }
1196
1197 /**
1198 * Combines this instant with a time-zone to create a {@code ZonedDateTime}.
1199 * <p>
1200 * This returns an {@code ZonedDateTime} formed from this instant at the
1201 * specified time-zone. An exception will be thrown if the instant is too
1202 * large to fit into a zoned date-time.
1203 * <p>
1204 * This method is equivalent to
1205 * {@link ZonedDateTime#ofInstant(Instant, ZoneId) ZonedDateTime.ofInstant(this, zone)}.
1206 *
1207 * @param zone the zone to combine with, not null
1208 * @return the zoned date-time formed from this instant and the specified zone, not null
1209 * @throws DateTimeException if the result exceeds the supported range
1210 */
1211 public ZonedDateTime atZone(ZoneId zone) {
1212 return ZonedDateTime.ofInstant(this, zone);
1213 }
1214
1215 //-----------------------------------------------------------------------
1216 /**
1217 * Converts this instant to the number of milliseconds from the epoch
1218 * of 1970-01-01T00:00:00Z.
1219 * <p>
1220 * If this instant represents a point on the time-line too far in the future
1221 * or past to fit in a {@code long} milliseconds, then an exception is thrown.
1222 * <p>
1223 * If this instant has greater than millisecond precision, then the conversion
1224 * will drop any excess precision information as though the amount in nanoseconds
1225 * was subject to integer division by one million.
1226 *
1227 * @return the number of milliseconds since the epoch of 1970-01-01T00:00:00Z
1228 * @throws ArithmeticException if numeric overflow occurs
1229 */
1230 public long toEpochMilli() {
1231 if (seconds < 0 && nanos > 0) {
1232 long millis = Math.multiplyExact(seconds+1, 1000);
1233 long adjustment = nanos / 1000_000 - 1000;
1234 return Math.addExact(millis, adjustment);
1235 } else {
1236 long millis = Math.multiplyExact(seconds, 1000);
1237 return Math.addExact(millis, nanos / 1000_000);
1238 }
1239 }
1240
1241 //-----------------------------------------------------------------------
1242 /**
1243 * Compares this instant to the specified instant.
1244 * <p>
1245 * The comparison is based on the time-line position of the instants.
1246 * It is "consistent with equals", as defined by {@link Comparable}.
1247 *
1248 * @param otherInstant the other instant to compare to, not null
1249 * @return the comparator value, negative if less, positive if greater
1250 * @throws NullPointerException if otherInstant is null
1251 */
1252 @Override
1253 public int compareTo(Instant otherInstant) {
1254 int cmp = Long.compare(seconds, otherInstant.seconds);
1255 if (cmp != 0) {
1256 return cmp;
1257 }
1258 return nanos - otherInstant.nanos;
1259 }
1260
1261 /**
1262 * Checks if this instant is after the specified instant.
1263 * <p>
1264 * The comparison is based on the time-line position of the instants.
1265 *
1266 * @param otherInstant the other instant to compare to, not null
1267 * @return true if this instant is after the specified instant
1268 * @throws NullPointerException if otherInstant is null
1269 */
1270 public boolean isAfter(Instant otherInstant) {
1271 return compareTo(otherInstant) > 0;
1272 }
1273
1274 /**
1275 * Checks if this instant is before the specified instant.
1276 * <p>
1277 * The comparison is based on the time-line position of the instants.
1278 *
1279 * @param otherInstant the other instant to compare to, not null
1280 * @return true if this instant is before the specified instant
1281 * @throws NullPointerException if otherInstant is null
1282 */
1283 public boolean isBefore(Instant otherInstant) {
1284 return compareTo(otherInstant) < 0;
1285 }
1286
1287 //-----------------------------------------------------------------------
1288 /**
1289 * Checks if this instant is equal to the specified instant.
1290 * <p>
1291 * The comparison is based on the time-line position of the instants.
1292 *
1293 * @param otherInstant the other instant, null returns false
1294 * @return true if the other instant is equal to this one
1295 */
1296 @Override
1297 public boolean equals(Object otherInstant) {
1298 if (this == otherInstant) {
1299 return true;
1300 }
1301 if (otherInstant instanceof Instant) {
1302 Instant other = (Instant) otherInstant;
1303 return this.seconds == other.seconds &&
1304 this.nanos == other.nanos;
1305 }
1306 return false;
1307 }
1308
1309 /**
1310 * Returns a hash code for this instant.
1311 *
1312 * @return a suitable hash code
1313 */
1314 @Override
1315 public int hashCode() {
1316 return ((int) (seconds ^ (seconds >>> 32))) + 51 * nanos;
1317 }
1318
1319 //-----------------------------------------------------------------------
1320 /**
1321 * A string representation of this instant using ISO-8601 representation.
1322 * <p>
1323 * The format used is the same as {@link DateTimeFormatter#ISO_INSTANT}.
1324 *
1325 * @return an ISO-8601 representation of this instant, not null
1326 */
1327 @Override
1328 public String toString() {
1329 return DateTimeFormatter.ISO_INSTANT.format(this);
1330 }
1331
1332 // -----------------------------------------------------------------------
1333 /**
1334 * Writes the object using a
1335 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1336 * @serialData
1337 * <pre>
1338 * out.writeByte(2); // identifies an Instant
1339 * out.writeLong(seconds);
1340 * out.writeInt(nanos);
1341 * </pre>
1342 *
1343 * @return the instance of {@code Ser}, not null
1344 */
1345 private Object writeReplace() {
1346 return new Ser(Ser.INSTANT_TYPE, this);
1347 }
1348
1349 /**
1350 * Defend against malicious streams.
1351 *
1352 * @param s the stream to read
1353 * @throws InvalidObjectException always
1354 */
1355 private void readObject(ObjectInputStream s) throws InvalidObjectException {
1356 throw new InvalidObjectException("Deserialization via serialization delegate");
1357 }
1358
1359 void writeExternal(DataOutput out) throws IOException {
1360 out.writeLong(seconds);
1361 out.writeInt(nanos);
1362 }
1363
1364 static Instant readExternal(DataInput in) throws IOException {
1365 long seconds = in.readLong();
1366 int nanos = in.readInt();
1367 return Instant.ofEpochSecond(seconds, nanos);
1368 }
1369
1370 }
1371