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.SECONDS_PER_DAY;
65 import static java.time.LocalTime.SECONDS_PER_HOUR;
66 import static java.time.LocalTime.SECONDS_PER_MINUTE;
67 import static java.time.temporal.ChronoField.INSTANT_SECONDS;
68 import static java.time.temporal.ChronoField.MICRO_OF_SECOND;
69 import static java.time.temporal.ChronoField.MILLI_OF_SECOND;
70 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
71 import static java.time.temporal.ChronoUnit.NANOS;
72
73 import java.io.DataInput;
74 import java.io.DataOutput;
75 import java.io.IOException;
76 import java.io.InvalidObjectException;
77 import java.io.ObjectStreamException;
78 import java.io.Serializable;
79 import java.time.format.DateTimeFormatters;
80 import java.time.format.DateTimeParseException;
81 import java.time.temporal.ChronoField;
82 import java.time.temporal.ChronoUnit;
83 import java.time.temporal.Queries;
84 import java.time.temporal.Temporal;
85 import java.time.temporal.TemporalAccessor;
86 import java.time.temporal.TemporalAdder;
87 import java.time.temporal.TemporalAdjuster;
88 import java.time.temporal.TemporalField;
89 import java.time.temporal.TemporalQuery;
90 import java.time.temporal.TemporalSubtractor;
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 * Constant for nanos per second.
230 */
231 private static final int NANOS_PER_SECOND = 1000_000_000;
232
233 /**
234 * The number of seconds from the epoch of 1970-01-01T00:00:00Z.
235 */
236 private final long seconds;
237 /**
238 * The number of nanoseconds, later along the time-line, from the seconds field.
239 * This is always positive, and never exceeds 999,999,999.
240 */
241 private final int nanos;
242
243 //-----------------------------------------------------------------------
244 /**
245 * Obtains the current instant from the system clock.
246 * <p>
247 * This will query the {@link Clock#systemUTC() system UTC clock} to
248 * obtain the current instant.
249 * <p>
250 * Using this method will prevent the ability to use an alternate time-source for
251 * testing because the clock is effectively hard-coded.
252 *
253 * @return the current instant using the system clock, not null
254 */
255 public static Instant now() {
256 return Clock.systemUTC().instant();
257 }
258
259 /**
260 * Obtains the current instant from the specified clock.
261 * <p>
262 * This will query the specified clock to obtain the current time.
263 * <p>
264 * Using this method allows the use of an alternate clock for testing.
265 * The alternate clock may be introduced using {@link Clock dependency injection}.
266 *
267 * @param clock the clock to use, not null
268 * @return the current instant, not null
269 */
270 public static Instant now(Clock clock) {
271 Objects.requireNonNull(clock, "clock");
272 return clock.instant();
273 }
274
275 //-----------------------------------------------------------------------
276 /**
277 * Obtains an instance of {@code Instant} using seconds from the
278 * epoch of 1970-01-01T00:00:00Z.
279 * <p>
280 * The nanosecond field is set to zero.
281 *
282 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
283 * @return an instant, not null
284 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
285 */
286 public static Instant ofEpochSecond(long epochSecond) {
287 return create(epochSecond, 0);
288 }
289
290 /**
291 * Obtains an instance of {@code Instant} using seconds from the
292 * epoch of 1970-01-01T00:00:00Z and nanosecond fraction of second.
293 * <p>
294 * This method allows an arbitrary number of nanoseconds to be passed in.
295 * The factory will alter the values of the second and nanosecond in order
296 * to ensure that the stored nanosecond is in the range 0 to 999,999,999.
297 * For example, the following will result in the exactly the same instant:
298 * <pre>
299 * Instant.ofSeconds(3, 1);
300 * Instant.ofSeconds(4, -999_999_999);
301 * Instant.ofSeconds(2, 1000_000_001);
302 * </pre>
303 *
304 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
305 * @param nanoAdjustment the nanosecond adjustment to the number of seconds, positive or negative
306 * @return an instant, not null
307 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
308 * @throws ArithmeticException if numeric overflow occurs
309 */
310 public static Instant ofEpochSecond(long epochSecond, long nanoAdjustment) {
311 long secs = Math.addExact(epochSecond, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND));
312 int nos = (int)Math.floorMod(nanoAdjustment, NANOS_PER_SECOND);
313 return create(secs, nos);
314 }
315
316 /**
317 * Obtains an instance of {@code Instant} using milliseconds from the
318 * epoch of 1970-01-01T00:00:00Z.
319 * <p>
320 * The seconds and nanoseconds are extracted from the specified milliseconds.
321 *
322 * @param epochMilli the number of milliseconds from 1970-01-01T00:00:00Z
323 * @return an instant, not null
324 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
325 */
326 public static Instant ofEpochMilli(long epochMilli) {
327 long secs = Math.floorDiv(epochMilli, 1000);
328 int mos = (int)Math.floorMod(epochMilli, 1000);
329 return create(secs, mos * 1000_000);
330 }
331
332 //-----------------------------------------------------------------------
333 /**
334 * Obtains an instance of {@code Instant} from a temporal object.
335 * <p>
336 * A {@code TemporalAccessor} represents some form of date and time information.
337 * This factory converts the arbitrary temporal object to an instance of {@code Instant}.
338 * <p>
339 * The conversion extracts the {@link ChronoField#INSTANT_SECONDS INSTANT_SECONDS}
340 * and {@link ChronoField#NANO_OF_SECOND NANO_OF_SECOND} fields.
341 * <p>
342 * This method matches the signature of the functional interface {@link TemporalQuery}
343 * allowing it to be used as a query via method reference, {@code Instant::from}.
344 *
345 * @param temporal the temporal object to convert, not null
346 * @return the instant, not null
347 * @throws DateTimeException if unable to convert to an {@code Instant}
348 */
349 public static Instant from(TemporalAccessor temporal) {
350 long instantSecs = temporal.getLong(INSTANT_SECONDS);
351 int nanoOfSecond = temporal.get(NANO_OF_SECOND);
352 return Instant.ofEpochSecond(instantSecs, nanoOfSecond);
353 }
354
355 //-----------------------------------------------------------------------
356 /**
357 * Obtains an instance of {@code Instant} from a text string such as
358 * {@code 2007-12-03T10:15:30:00}.
359 * <p>
360 * The string must represent a valid instant in UTC and is parsed using
361 * {@link DateTimeFormatters#isoInstant()}.
362 *
363 * @param text the text to parse, not null
364 * @return the parsed instant, not null
365 * @throws DateTimeParseException if the text cannot be parsed
366 */
367 public static Instant parse(final CharSequence text) {
368 return DateTimeFormatters.isoInstant().parse(text, Instant::from);
369 }
370
371 //-----------------------------------------------------------------------
372 /**
373 * Obtains an instance of {@code Instant} using seconds and nanoseconds.
374 *
375 * @param seconds the length of the duration in seconds
376 * @param nanoOfSecond the nano-of-second, from 0 to 999,999,999
377 * @throws DateTimeException if the instant exceeds the maximum or minimum instant
378 */
379 private static Instant create(long seconds, int nanoOfSecond) {
380 if ((seconds | nanoOfSecond) == 0) {
381 return EPOCH;
382 }
383 if (seconds < MIN_SECOND || seconds > MAX_SECOND) {
384 throw new DateTimeException("Instant exceeds minimum or maximum instant");
385 }
386 return new Instant(seconds, nanoOfSecond);
387 }
388
389 /**
390 * Constructs an instance of {@code Instant} using seconds from the epoch of
391 * 1970-01-01T00:00:00Z and nanosecond fraction of second.
392 *
393 * @param epochSecond the number of seconds from 1970-01-01T00:00:00Z
394 * @param nanos the nanoseconds within the second, must be positive
395 */
396 private Instant(long epochSecond, int nanos) {
397 super();
398 this.seconds = epochSecond;
399 this.nanos = nanos;
400 }
401
402 //-----------------------------------------------------------------------
403 /**
404 * Checks if the specified field is supported.
405 * <p>
406 * This checks if this instant can be queried for the specified field.
407 * If false, then calling the {@link #range(TemporalField) range} and
408 * {@link #get(TemporalField) get} methods will throw an exception.
409 * <p>
410 * If the field is a {@link ChronoField} then the query is implemented here.
411 * The supported fields are:
412 * <ul>
413 * <li>{@code NANO_OF_SECOND}
414 * <li>{@code MICRO_OF_SECOND}
415 * <li>{@code MILLI_OF_SECOND}
416 * <li>{@code INSTANT_SECONDS}
417 * </ul>
418 * All other {@code ChronoField} instances will return false.
419 * <p>
420 * If the field is not a {@code ChronoField}, then the result of this method
421 * is obtained by invoking {@code TemporalField.doIsSupported(TemporalAccessor)}
422 * passing {@code this} as the argument.
423 * Whether the field is supported is determined by the field.
424 *
425 * @param field the field to check, null returns false
426 * @return true if the field is supported on this instant, false if not
427 */
428 @Override
429 public boolean isSupported(TemporalField field) {
430 if (field instanceof ChronoField) {
431 return field == INSTANT_SECONDS || field == NANO_OF_SECOND || field == MICRO_OF_SECOND || field == MILLI_OF_SECOND;
432 }
433 return field != null && field.doIsSupported(this);
434 }
435
436 /**
437 * Gets the range of valid values for the specified field.
438 * <p>
439 * The range object expresses the minimum and maximum valid values for a field.
440 * This instant is used to enhance the accuracy of the returned range.
441 * If it is not possible to return the range, because the field is not supported
442 * or for some other reason, an exception is thrown.
443 * <p>
444 * If the field is a {@link ChronoField} then the query is implemented here.
445 * The {@link #isSupported(TemporalField) supported fields} will return
446 * appropriate range instances.
447 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
448 * <p>
449 * If the field is not a {@code ChronoField}, then the result of this method
450 * is obtained by invoking {@code TemporalField.doRange(TemporalAccessor)}
451 * passing {@code this} as the argument.
452 * Whether the range can be obtained is determined by the field.
453 *
454 * @param field the field to query the range for, not null
455 * @return the range of valid values for the field, not null
456 * @throws DateTimeException if the range for the field cannot be obtained
457 */
458 @Override // override for Javadoc
459 public ValueRange range(TemporalField field) {
460 return Temporal.super.range(field);
461 }
462
463 /**
464 * Gets the value of the specified field from this instant as an {@code int}.
465 * <p>
466 * This queries this instant for the value for the specified field.
467 * The returned value will always be within the valid range of values for the field.
468 * If it is not possible to return the value, because the field is not supported
469 * or for some other reason, an exception is thrown.
470 * <p>
471 * If the field is a {@link ChronoField} then the query is implemented here.
472 * The {@link #isSupported(TemporalField) supported fields} will return valid
473 * values based on this date-time, except {@code INSTANT_SECONDS} which is too
474 * large to fit in an {@code int} and throws a {@code DateTimeException}.
475 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
476 * <p>
477 * If the field is not a {@code ChronoField}, then the result of this method
478 * is obtained by invoking {@code TemporalField.doGet(TemporalAccessor)}
479 * passing {@code this} as the argument. Whether the value can be obtained,
480 * and what the value represents, is determined by the field.
481 *
482 * @param field the field to get, not null
483 * @return the value for the field
484 * @throws DateTimeException if a value for the field cannot be obtained
485 * @throws ArithmeticException if numeric overflow occurs
486 */
487 @Override // override for Javadoc and performance
488 public int get(TemporalField field) {
489 if (field instanceof ChronoField) {
490 switch ((ChronoField) field) {
491 case NANO_OF_SECOND: return nanos;
492 case MICRO_OF_SECOND: return nanos / 1000;
493 case MILLI_OF_SECOND: return nanos / 1000_000;
494 case INSTANT_SECONDS: INSTANT_SECONDS.checkValidIntValue(seconds);
495 }
496 throw new DateTimeException("Unsupported field: " + field.getName());
497 }
498 return range(field).checkValidIntValue(field.doGet(this), field);
499 }
500
501 /**
502 * Gets the value of the specified field from this instant as a {@code long}.
503 * <p>
504 * This queries this instant for the value for the specified field.
505 * If it is not possible to return the value, because the field is not supported
506 * or for some other reason, an exception is thrown.
507 * <p>
508 * If the field is a {@link ChronoField} then the query is implemented here.
509 * The {@link #isSupported(TemporalField) supported fields} will return valid
510 * values based on this date-time.
511 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
512 * <p>
513 * If the field is not a {@code ChronoField}, then the result of this method
514 * is obtained by invoking {@code TemporalField.doGet(TemporalAccessor)}
515 * passing {@code this} as the argument. Whether the value can be obtained,
516 * and what the value represents, is determined by the field.
517 *
518 * @param field the field to get, not null
519 * @return the value for the field
520 * @throws DateTimeException if a value for the field cannot be obtained
521 * @throws ArithmeticException if numeric overflow occurs
522 */
523 @Override
524 public long getLong(TemporalField field) {
525 if (field instanceof ChronoField) {
526 switch ((ChronoField) field) {
527 case NANO_OF_SECOND: return nanos;
528 case MICRO_OF_SECOND: return nanos / 1000;
529 case MILLI_OF_SECOND: return nanos / 1000_000;
530 case INSTANT_SECONDS: return seconds;
531 }
532 throw new DateTimeException("Unsupported field: " + field.getName());
533 }
534 return field.doGet(this);
535 }
536
537 //-----------------------------------------------------------------------
538 /**
539 * Gets the number of seconds from the Java epoch of 1970-01-01T00:00:00Z.
540 * <p>
541 * The epoch second count is a simple incrementing count of seconds where
542 * second 0 is 1970-01-01T00:00:00Z.
543 * The nanosecond part of the day is returned by {@code getNanosOfSecond}.
544 *
545 * @return the seconds from the epoch of 1970-01-01T00:00:00Z
546 */
547 public long getEpochSecond() {
548 return seconds;
549 }
550
551 /**
552 * Gets the number of nanoseconds, later along the time-line, from the start
553 * of the second.
554 * <p>
555 * The nanosecond-of-second value measures the total number of nanoseconds from
556 * the second returned by {@code getEpochSecond}.
557 *
558 * @return the nanoseconds within the second, always positive, never exceeds 999,999,999
559 */
560 public int getNano() {
561 return nanos;
562 }
563
564 //-------------------------------------------------------------------------
565 /**
566 * Returns an adjusted copy of this instant.
567 * <p>
568 * This returns a new {@code Instant}, based on this one, with the date adjusted.
569 * The adjustment takes place using the specified adjuster strategy object.
570 * Read the documentation of the adjuster to understand what adjustment will be made.
571 * <p>
572 * The result of this method is obtained by invoking the
573 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
574 * specified adjuster passing {@code this} as the argument.
575 * <p>
576 * This instance is immutable and unaffected by this method call.
577 *
578 * @param adjuster the adjuster to use, not null
579 * @return an {@code Instant} based on {@code this} with the adjustment made, not null
580 * @throws DateTimeException if the adjustment cannot be made
581 * @throws ArithmeticException if numeric overflow occurs
582 */
583 @Override
584 public Instant with(TemporalAdjuster adjuster) {
585 return (Instant) adjuster.adjustInto(this);
586 }
587
588 /**
589 * Returns a copy of this instant with the specified field set to a new value.
590 * <p>
591 * This returns a new {@code Instant}, based on this one, with the value
592 * for the specified field changed.
593 * If it is not possible to set the value, because the field is not supported or for
594 * some other reason, an exception is thrown.
595 * <p>
596 * If the field is a {@link ChronoField} then the adjustment is implemented here.
597 * The supported fields behave as follows:
598 * <ul>
599 * <li>{@code NANO_OF_SECOND} -
600 * Returns an {@code Instant} with the specified nano-of-second.
601 * The epoch-second will be unchanged.
602 * <li>{@code MICRO_OF_SECOND} -
603 * Returns an {@code Instant} with the nano-of-second replaced by the specified
604 * micro-of-second multiplied by 1,000. The epoch-second will be unchanged.
605 * <li>{@code MILLI_OF_SECOND} -
606 * Returns an {@code Instant} with the nano-of-second replaced by the specified
607 * milli-of-second multiplied by 1,000,000. The epoch-second will be unchanged.
608 * <li>{@code INSTANT_SECONDS} -
609 * Returns an {@code Instant} with the specified epoch-second.
610 * The nano-of-second will be unchanged.
611 * </ul>
612 * <p>
613 * In all cases, if the new value is outside the valid range of values for the field
614 * then a {@code DateTimeException} will be thrown.
615 * <p>
616 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
617 * <p>
618 * If the field is not a {@code ChronoField}, then the result of this method
619 * is obtained by invoking {@code TemporalField.doWith(Temporal, long)}
620 * passing {@code this} as the argument. In this case, the field determines
621 * whether and how to adjust the instant.
622 * <p>
623 * This instance is immutable and unaffected by this method call.
624 *
625 * @param field the field to set in the result, not null
626 * @param newValue the new value of the field in the result
627 * @return an {@code Instant} based on {@code this} with the specified field set, not null
628 * @throws DateTimeException if the field cannot be set
629 * @throws ArithmeticException if numeric overflow occurs
630 */
631 @Override
632 public Instant with(TemporalField field, long newValue) {
633 if (field instanceof ChronoField) {
634 ChronoField f = (ChronoField) field;
635 f.checkValidValue(newValue);
636 switch (f) {
637 case MILLI_OF_SECOND: {
638 int nval = (int) newValue * 1000_000;
639 return (nval != nanos ? create(seconds, nval) : this);
640 }
641 case MICRO_OF_SECOND: {
642 int nval = (int) newValue * 1000;
643 return (nval != nanos ? create(seconds, nval) : this);
644 }
645 case NANO_OF_SECOND: return (newValue != nanos ? create(seconds, (int) newValue) : this);
646 case INSTANT_SECONDS: return (newValue != seconds ? create(newValue, nanos) : this);
647 }
648 throw new DateTimeException("Unsupported field: " + field.getName());
649 }
650 return field.doWith(this, newValue);
651 }
652
653 //-----------------------------------------------------------------------
654 /**
655 * {@inheritDoc}
656 * @throws DateTimeException {@inheritDoc}
657 * @throws ArithmeticException {@inheritDoc}
658 */
659 @Override
660 public Instant plus(TemporalAdder adder) {
661 return (Instant) adder.addTo(this);
662 }
663
664 /**
665 * {@inheritDoc}
666 * @throws DateTimeException {@inheritDoc}
667 * @throws ArithmeticException {@inheritDoc}
668 */
669 @Override
670 public Instant plus(long amountToAdd, TemporalUnit unit) {
671 if (unit instanceof ChronoUnit) {
672 switch ((ChronoUnit) unit) {
673 case NANOS: return plusNanos(amountToAdd);
674 case MICROS: return plus(amountToAdd / 1000_000, (amountToAdd % 1000_000) * 1000);
675 case MILLIS: return plusMillis(amountToAdd);
676 case SECONDS: return plusSeconds(amountToAdd);
677 case MINUTES: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_MINUTE));
678 case HOURS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_HOUR));
679 case HALF_DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY / 2));
680 case DAYS: return plusSeconds(Math.multiplyExact(amountToAdd, SECONDS_PER_DAY));
681 }
682 throw new DateTimeException("Unsupported unit: " + unit.getName());
683 }
684 return unit.doPlus(this, amountToAdd);
685 }
686
687 //-----------------------------------------------------------------------
688 /**
689 * Returns a copy of this instant with the specified duration in seconds added.
690 * <p>
691 * This instance is immutable and unaffected by this method call.
692 *
693 * @param secondsToAdd the seconds to add, positive or negative
694 * @return an {@code Instant} based on this instant with the specified seconds added, not null
695 * @throws DateTimeException if the result exceeds the maximum or minimum instant
696 * @throws ArithmeticException if numeric overflow occurs
697 */
698 public Instant plusSeconds(long secondsToAdd) {
699 return plus(secondsToAdd, 0);
700 }
701
702 /**
703 * Returns a copy of this instant with the specified duration in milliseconds added.
704 * <p>
705 * This instance is immutable and unaffected by this method call.
706 *
707 * @param millisToAdd the milliseconds to add, positive or negative
708 * @return an {@code Instant} based on this instant with the specified milliseconds added, not null
709 * @throws DateTimeException if the result exceeds the maximum or minimum instant
710 * @throws ArithmeticException if numeric overflow occurs
711 */
712 public Instant plusMillis(long millisToAdd) {
713 return plus(millisToAdd / 1000, (millisToAdd % 1000) * 1000_000);
714 }
715
716 /**
717 * Returns a copy of this instant with the specified duration in nanoseconds added.
718 * <p>
719 * This instance is immutable and unaffected by this method call.
720 *
721 * @param nanosToAdd the nanoseconds to add, positive or negative
722 * @return an {@code Instant} based on this instant with the specified nanoseconds added, not null
723 * @throws DateTimeException if the result exceeds the maximum or minimum instant
724 * @throws ArithmeticException if numeric overflow occurs
725 */
726 public Instant plusNanos(long nanosToAdd) {
727 return plus(0, nanosToAdd);
728 }
729
730 /**
731 * Returns a copy of this instant with the specified duration added.
732 * <p>
733 * This instance is immutable and unaffected by this method call.
734 *
735 * @param secondsToAdd the seconds to add, positive or negative
736 * @param nanosToAdd the nanos to add, positive or negative
737 * @return an {@code Instant} based on this instant with the specified seconds added, not null
738 * @throws DateTimeException if the result exceeds the maximum or minimum instant
739 * @throws ArithmeticException if numeric overflow occurs
740 */
741 private Instant plus(long secondsToAdd, long nanosToAdd) {
742 if ((secondsToAdd | nanosToAdd) == 0) {
743 return this;
744 }
745 long epochSec = Math.addExact(seconds, secondsToAdd);
746 epochSec = Math.addExact(epochSec, nanosToAdd / NANOS_PER_SECOND);
747 nanosToAdd = nanosToAdd % NANOS_PER_SECOND;
748 long nanoAdjustment = nanos + nanosToAdd; // safe int+NANOS_PER_SECOND
749 return ofEpochSecond(epochSec, nanoAdjustment);
750 }
751
752 //-----------------------------------------------------------------------
753 /**
754 * {@inheritDoc}
755 * @throws DateTimeException {@inheritDoc}
756 * @throws ArithmeticException {@inheritDoc}
757 */
758 @Override
759 public Instant minus(TemporalSubtractor subtractor) {
760 return (Instant) subtractor.subtractFrom(this);
761 }
762
763 /**
764 * {@inheritDoc}
765 * @throws DateTimeException {@inheritDoc}
766 * @throws ArithmeticException {@inheritDoc}
767 */
768 @Override
769 public Instant minus(long amountToSubtract, TemporalUnit unit) {
770 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
771 }
772
773 //-----------------------------------------------------------------------
774 /**
775 * Returns a copy of this instant with the specified duration in seconds subtracted.
776 * <p>
777 * This instance is immutable and unaffected by this method call.
778 *
779 * @param secondsToSubtract the seconds to subtract, positive or negative
780 * @return an {@code Instant} based on this instant with the specified seconds subtracted, not null
781 * @throws DateTimeException if the result exceeds the maximum or minimum instant
782 * @throws ArithmeticException if numeric overflow occurs
783 */
784 public Instant minusSeconds(long secondsToSubtract) {
785 if (secondsToSubtract == Long.MIN_VALUE) {
786 return plusSeconds(Long.MAX_VALUE).plusSeconds(1);
787 }
788 return plusSeconds(-secondsToSubtract);
789 }
790
791 /**
792 * Returns a copy of this instant with the specified duration in milliseconds subtracted.
793 * <p>
794 * This instance is immutable and unaffected by this method call.
795 *
796 * @param millisToSubtract the milliseconds to subtract, positive or negative
797 * @return an {@code Instant} based on this instant with the specified milliseconds subtracted, 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 minusMillis(long millisToSubtract) {
802 if (millisToSubtract == Long.MIN_VALUE) {
803 return plusMillis(Long.MAX_VALUE).plusMillis(1);
804 }
805 return plusMillis(-millisToSubtract);
806 }
807
808 /**
809 * Returns a copy of this instant with the specified duration in nanoseconds subtracted.
810 * <p>
811 * This instance is immutable and unaffected by this method call.
812 *
813 * @param nanosToSubtract the nanoseconds to subtract, positive or negative
814 * @return an {@code Instant} based on this instant with the specified nanoseconds subtracted, not null
815 * @throws DateTimeException if the result exceeds the maximum or minimum instant
816 * @throws ArithmeticException if numeric overflow occurs
817 */
818 public Instant minusNanos(long nanosToSubtract) {
819 if (nanosToSubtract == Long.MIN_VALUE) {
820 return plusNanos(Long.MAX_VALUE).plusNanos(1);
821 }
822 return plusNanos(-nanosToSubtract);
823 }
824
825 //-------------------------------------------------------------------------
826 /**
827 * Queries this instant using the specified query.
828 * <p>
829 * This queries this instant using the specified query strategy object.
830 * The {@code TemporalQuery} object defines the logic to be used to
831 * obtain the result. Read the documentation of the query to understand
832 * what the result of this method will be.
833 * <p>
834 * The result of this method is obtained by invoking the
835 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
836 * specified query passing {@code this} as the argument.
837 *
838 * @param <R> the type of the result
839 * @param query the query to invoke, not null
840 * @return the query result, null may be returned (defined by the query)
841 * @throws DateTimeException if unable to query (defined by the query)
842 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
843 */
844 @SuppressWarnings("unchecked")
845 @Override
846 public <R> R query(TemporalQuery<R> query) {
847 if (query == Queries.precision()) {
848 return (R) NANOS;
849 }
850 // inline TemporalAccessor.super.query(query) as an optimization
851 if (query == Queries.chrono() || query == Queries.zoneId() || query == Queries.zone() || query == Queries.offset()) {
852 return null;
853 }
854 return query.queryFrom(this);
855 }
856
857 /**
858 * Adjusts the specified temporal object to have this instant.
859 * <p>
860 * This returns a temporal object of the same observable type as the input
861 * with the instant changed to be the same as this.
862 * <p>
863 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
864 * twice, passing {@link ChronoField#INSTANT_SECONDS} and
865 * {@link ChronoField#NANO_OF_SECOND} as the fields.
866 * <p>
867 * In most cases, it is clearer to reverse the calling pattern by using
868 * {@link Temporal#with(TemporalAdjuster)}:
869 * <pre>
870 * // these two lines are equivalent, but the second approach is recommended
871 * temporal = thisInstant.adjustInto(temporal);
872 * temporal = temporal.with(thisInstant);
873 * </pre>
874 * <p>
875 * This instance is immutable and unaffected by this method call.
876 *
877 * @param temporal the target object to be adjusted, not null
878 * @return the adjusted object, not null
879 * @throws DateTimeException if unable to make the adjustment
880 * @throws ArithmeticException if numeric overflow occurs
881 */
882 @Override
883 public Temporal adjustInto(Temporal temporal) {
884 return temporal.with(INSTANT_SECONDS, seconds).with(NANO_OF_SECOND, nanos);
885 }
886
887 /**
888 * Calculates the period between this instant and another instant in
889 * terms of the specified unit.
890 * <p>
891 * This calculates the period between two instants in terms of a single unit.
892 * The start and end points are {@code this} and the specified instant.
893 * The result will be negative if the end is before the start.
894 * The calculation returns a whole number, representing the number of
895 * complete units between the two instants.
896 * The {@code Temporal} passed to this method must be an {@code Instant}.
897 * For example, the period in days between two dates can be calculated
898 * using {@code startInstant.periodUntil(endInstant, SECONDS)}.
899 * <p>
900 * This method operates in association with {@link TemporalUnit#between}.
901 * The result of this method is a {@code long} representing the amount of
902 * the specified unit. By contrast, the result of {@code between} is an
903 * object that can be used directly in addition/subtraction:
904 * <pre>
905 * long period = start.periodUntil(end, SECONDS); // this method
906 * dateTime.plus(SECONDS.between(start, end)); // use in plus/minus
907 * </pre>
908 * <p>
909 * The calculation is implemented in this method for {@link ChronoUnit}.
910 * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
911 * {@code MINUTES}, {@code HOURS}, {@code HALF_DAYS} and {@code DAYS}
912 * are supported. Other {@code ChronoUnit} values will throw an exception.
913 * <p>
914 * If the unit is not a {@code ChronoUnit}, then the result of this method
915 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
916 * passing {@code this} as the first argument and the input temporal as
917 * the second argument.
918 * <p>
919 * This instance is immutable and unaffected by this method call.
920 *
921 * @param endInstant the end date, which must be a {@code LocalDate}, not null
922 * @param unit the unit to measure the period in, not null
923 * @return the amount of the period between this date and the end date
924 * @throws DateTimeException if the period cannot be calculated
925 * @throws ArithmeticException if numeric overflow occurs
926 */
927 @Override
928 public long periodUntil(Temporal endInstant, TemporalUnit unit) {
929 if (endInstant instanceof Instant == false) {
930 Objects.requireNonNull(endInstant, "endInstant");
931 throw new DateTimeException("Unable to calculate period between objects of two different types");
932 }
933 Instant end = (Instant) endInstant;
934 if (unit instanceof ChronoUnit) {
935 ChronoUnit f = (ChronoUnit) unit;
936 switch (f) {
937 case NANOS: return nanosUntil(end);
938 case MICROS: return nanosUntil(end) / 1000;
939 case MILLIS: return Math.subtractExact(end.toEpochMilli(), toEpochMilli());
940 case SECONDS: return secondsUntil(end);
941 case MINUTES: return secondsUntil(end) / SECONDS_PER_MINUTE;
942 case HOURS: return secondsUntil(end) / SECONDS_PER_HOUR;
943 case HALF_DAYS: return secondsUntil(end) / (12 * SECONDS_PER_HOUR);
944 case DAYS: return secondsUntil(end) / (SECONDS_PER_DAY);
945 }
946 throw new DateTimeException("Unsupported unit: " + unit.getName());
947 }
948 return unit.between(this, endInstant).getAmount();
949 }
950
951 private long nanosUntil(Instant end) {
952 long secs = Math.multiplyExact(secondsUntil(end), NANOS_PER_SECOND);
953 return Math.addExact(secs, end.nanos - nanos);
954 }
955
956 private long secondsUntil(Instant end) {
957 return Math.subtractExact(end.seconds, seconds);
958 }
959
960 //-----------------------------------------------------------------------
961 /**
962 * Converts this instant to the number of milliseconds from the epoch
963 * of 1970-01-01T00:00:00Z.
964 * <p>
965 * If this instant represents a point on the time-line too far in the future
966 * or past to fit in a {@code long} milliseconds, then an exception is thrown.
967 * <p>
968 * If this instant has greater than millisecond precision, then the conversion
969 * will drop any excess precision information as though the amount in nanoseconds
970 * was subject to integer division by one million.
971 *
972 * @return the number of milliseconds since the epoch of 1970-01-01T00:00:00Z
973 * @throws ArithmeticException if numeric overflow occurs
974 */
975 public long toEpochMilli() {
976 long millis = Math.multiplyExact(seconds, 1000);
977 return millis + nanos / 1000_000;
978 }
979
980 //-----------------------------------------------------------------------
981 /**
982 * Compares this instant to the specified instant.
983 * <p>
984 * The comparison is based on the time-line position of the instants.
985 * It is "consistent with equals", as defined by {@link Comparable}.
986 *
987 * @param otherInstant the other instant to compare to, not null
988 * @return the comparator value, negative if less, positive if greater
989 * @throws NullPointerException if otherInstant is null
990 */
991 @Override
992 public int compareTo(Instant otherInstant) {
993 int cmp = Long.compare(seconds, otherInstant.seconds);
994 if (cmp != 0) {
995 return cmp;
996 }
997 return nanos - otherInstant.nanos;
998 }
999
1000 /**
1001 * Checks if this instant is after the specified instant.
1002 * <p>
1003 * The comparison is based on the time-line position of the instants.
1004 *
1005 * @param otherInstant the other instant to compare to, not null
1006 * @return true if this instant is after the specified instant
1007 * @throws NullPointerException if otherInstant is null
1008 */
1009 public boolean isAfter(Instant otherInstant) {
1010 return compareTo(otherInstant) > 0;
1011 }
1012
1013 /**
1014 * Checks if this instant is before the specified instant.
1015 * <p>
1016 * The comparison is based on the time-line position of the instants.
1017 *
1018 * @param otherInstant the other instant to compare to, not null
1019 * @return true if this instant is before the specified instant
1020 * @throws NullPointerException if otherInstant is null
1021 */
1022 public boolean isBefore(Instant otherInstant) {
1023 return compareTo(otherInstant) < 0;
1024 }
1025
1026 //-----------------------------------------------------------------------
1027 /**
1028 * Checks if this instant is equal to the specified instant.
1029 * <p>
1030 * The comparison is based on the time-line position of the instants.
1031 *
1032 * @param otherInstant the other instant, null returns false
1033 * @return true if the other instant is equal to this one
1034 */
1035 @Override
1036 public boolean equals(Object otherInstant) {
1037 if (this == otherInstant) {
1038 return true;
1039 }
1040 if (otherInstant instanceof Instant) {
1041 Instant other = (Instant) otherInstant;
1042 return this.seconds == other.seconds &&
1043 this.nanos == other.nanos;
1044 }
1045 return false;
1046 }
1047
1048 /**
1049 * Returns a hash code for this instant.
1050 *
1051 * @return a suitable hash code
1052 */
1053 @Override
1054 public int hashCode() {
1055 return ((int) (seconds ^ (seconds >>> 32))) + 51 * nanos;
1056 }
1057
1058 //-----------------------------------------------------------------------
1059 /**
1060 * A string representation of this instant using ISO-8601 representation.
1061 * <p>
1062 * The format used is the same as {@link DateTimeFormatters#isoInstant()}.
1063 *
1064 * @return an ISO-8601 representation of this instant, not null
1065 */
1066 @Override
1067 public String toString() {
1068 return DateTimeFormatters.isoInstant().print(this);
1069 }
1070
1071 // -----------------------------------------------------------------------
1072 /**
1073 * Writes the object using a
1074 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1075 * <pre>
1076 * out.writeByte(2); // identifies this as an Instant
1077 * out.writeLong(seconds);
1078 * out.writeInt(nanos);
1079 * </pre>
1080 *
1081 * @return the instance of {@code Ser}, not null
1082 */
1083 private Object writeReplace() {
1084 return new Ser(Ser.INSTANT_TYPE, this);
1085 }
1086
1087 /**
1088 * Defend against malicious streams.
1089 * @return never
1090 * @throws InvalidObjectException always
1091 */
1092 private Object readResolve() throws ObjectStreamException {
1093 throw new InvalidObjectException("Deserialization via serialization delegate");
1094 }
1095
1096 void writeExternal(DataOutput out) throws IOException {
1097 out.writeLong(seconds);
1098 out.writeInt(nanos);
1099 }
1100
1101 static Instant readExternal(DataInput in) throws IOException {
1102 long seconds = in.readLong();
1103 int nanos = in.readInt();
1104 return Instant.ofEpochSecond(seconds, nanos);
1105 }
1106
1107 }