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.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_MONTH;
66 import static java.time.temporal.ChronoField.ALIGNED_DAY_OF_WEEK_IN_YEAR;
67 import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_MONTH;
68 import static java.time.temporal.ChronoField.ALIGNED_WEEK_OF_YEAR;
69 import static java.time.temporal.ChronoField.DAY_OF_MONTH;
70 import static java.time.temporal.ChronoField.DAY_OF_YEAR;
71 import static java.time.temporal.ChronoField.EPOCH_DAY;
72 import static java.time.temporal.ChronoField.EPOCH_MONTH;
73 import static java.time.temporal.ChronoField.ERA;
74 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
75 import static java.time.temporal.ChronoField.YEAR;
76
77 import java.io.DataInput;
78 import java.io.DataOutput;
79 import java.io.IOException;
80 import java.io.InvalidObjectException;
81 import java.io.ObjectStreamException;
82 import java.io.Serializable;
83 import java.time.format.DateTimeBuilder;
84 import java.time.format.DateTimeFormatter;
85 import java.time.format.DateTimeFormatters;
86 import java.time.format.DateTimeParseException;
87 import java.time.temporal.ChronoField;
88 import java.time.temporal.ChronoLocalDate;
89 import java.time.temporal.ChronoUnit;
90 import java.time.temporal.Era;
91 import java.time.temporal.ISOChrono;
92 import java.time.temporal.OffsetDate;
93 import java.time.temporal.Temporal;
94 import java.time.temporal.TemporalAccessor;
95 import java.time.temporal.TemporalAdder;
96 import java.time.temporal.TemporalAdjuster;
97 import java.time.temporal.TemporalField;
98 import java.time.temporal.TemporalQuery;
99 import java.time.temporal.TemporalSubtractor;
100 import java.time.temporal.TemporalUnit;
101 import java.time.temporal.ValueRange;
102 import java.time.temporal.Year;
103 import java.time.zone.ZoneOffsetTransition;
104 import java.time.zone.ZoneRules;
105 import java.util.Objects;
106
107 /**
108 * A date without a time-zone in the ISO-8601 calendar system,
109 * such as {@code 2007-12-03}.
110 * <p>
111 * {@code LocalDate} is an immutable date-time object that represents a date,
112 * often viewed as year-month-day. Other date fields, such as day-of-year,
113 * day-of-week and week-of-year, can also be accessed.
114 * For example, the value "2nd October 2007" can be stored in a {@code LocalDate}.
115 * <p>
116 * This class does not store or represent a time or time-zone.
117 * Instead, it is a description of the date, as used for birthdays.
118 * It cannot represent an instant on the time-line without additional information
119 * such as an offset or time-zone.
120 * <p>
121 * The ISO-8601 calendar system is the modern civil calendar system used today
122 * in most of the world. It is equivalent to the proleptic Gregorian calendar
123 * system, in which today's rules for leap years are applied for all time.
124 * For most applications written today, the ISO-8601 rules are entirely suitable.
125 * However, any application that makes use of historical dates, and requires them
126 * to be accurate will find the ISO-8601 approach unsuitable.
127 *
128 * <h3>Specification for implementors</h3>
129 * This class is immutable and thread-safe.
130 *
131 * @since 1.8
132 */
133 public final class LocalDate
134 implements Temporal, TemporalAdjuster, ChronoLocalDate<ISOChrono>, Serializable {
135
136 /**
137 * The minimum supported {@code LocalDate}, '-999999999-01-01'.
138 * This could be used by an application as a "far past" date.
139 */
140 public static final LocalDate MIN = LocalDate.of(Year.MIN_VALUE, 1, 1);
141 /**
142 * The maximum supported {@code LocalDate}, '+999999999-12-31'.
143 * This could be used by an application as a "far future" date.
144 */
145 public static final LocalDate MAX = LocalDate.of(Year.MAX_VALUE, 12, 31);
146
147 /**
148 * Serialization version.
149 */
150 private static final long serialVersionUID = 2942565459149668126L;
151 /**
152 * The number of days in a 400 year cycle.
153 */
154 private static final int DAYS_PER_CYCLE = 146097;
155 /**
156 * The number of days from year zero to year 1970.
157 * There are five 400 year cycles from year zero to 2000.
158 * There are 7 leap years from 1970 to 2000.
159 */
160 static final long DAYS_0000_TO_1970 = (DAYS_PER_CYCLE * 5L) - (30L * 365L + 7L);
161
162 /**
163 * The year.
164 */
165 private final int year;
166 /**
167 * The month-of-year.
168 */
169 private final short month;
170 /**
171 * The day-of-month.
172 */
173 private final short day;
174
175 //-----------------------------------------------------------------------
176 /**
177 * Obtains the current date from the system clock in the default time-zone.
178 * <p>
179 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
180 * time-zone to obtain the current date.
181 * <p>
182 * Using this method will prevent the ability to use an alternate clock for testing
183 * because the clock is hard-coded.
184 *
185 * @return the current date using the system clock and default time-zone, not null
186 */
187 public static LocalDate now() {
188 return now(Clock.systemDefaultZone());
189 }
190
191 /**
192 * Obtains the current date from the system clock in the specified time-zone.
193 * <p>
194 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
195 * Specifying the time-zone avoids dependence on the default time-zone.
196 * <p>
197 * Using this method will prevent the ability to use an alternate clock for testing
198 * because the clock is hard-coded.
199 *
200 * @param zone the zone ID to use, not null
201 * @return the current date using the system clock, not null
202 */
203 public static LocalDate now(ZoneId zone) {
204 return now(Clock.system(zone));
205 }
206
207 /**
208 * Obtains the current date from the specified clock.
209 * <p>
210 * This will query the specified clock to obtain the current date - today.
211 * Using this method allows the use of an alternate clock for testing.
212 * The alternate clock may be introduced using {@link Clock dependency injection}.
213 *
214 * @param clock the clock to use, not null
215 * @return the current date, not null
216 */
217 public static LocalDate now(Clock clock) {
218 Objects.requireNonNull(clock, "clock");
219 // inline OffsetDate factory to avoid creating object and InstantProvider checks
220 final Instant now = clock.instant(); // called once
221 ZoneOffset offset = clock.getZone().getRules().getOffset(now);
222 long epochSec = now.getEpochSecond() + offset.getTotalSeconds(); // overflow caught later
223 long epochDay = Math.floorDiv(epochSec, SECONDS_PER_DAY);
224 return LocalDate.ofEpochDay(epochDay);
225 }
226
227 //-----------------------------------------------------------------------
228 /**
229 * Obtains an instance of {@code LocalDate} from a year, month and day.
230 * <p>
231 * The day must be valid for the year and month, otherwise an exception will be thrown.
232 *
233 * @param year the year to represent, from MIN_YEAR to MAX_YEAR
234 * @param month the month-of-year to represent, not null
235 * @param dayOfMonth the day-of-month to represent, from 1 to 31
236 * @return the local date, not null
237 * @throws DateTimeException if the value of any field is out of range
238 * @throws DateTimeException if the day-of-month is invalid for the month-year
239 */
240 public static LocalDate of(int year, Month month, int dayOfMonth) {
241 YEAR.checkValidValue(year);
242 Objects.requireNonNull(month, "month");
243 DAY_OF_MONTH.checkValidValue(dayOfMonth);
244 return create(year, month, dayOfMonth);
245 }
246
247 /**
248 * Obtains an instance of {@code LocalDate} from a year, month and day.
249 * <p>
250 * The day must be valid for the year and month, otherwise an exception will be thrown.
251 *
252 * @param year the year to represent, from MIN_YEAR to MAX_YEAR
253 * @param month the month-of-year to represent, from 1 (January) to 12 (December)
254 * @param dayOfMonth the day-of-month to represent, from 1 to 31
255 * @return the local date, not null
256 * @throws DateTimeException if the value of any field is out of range
257 * @throws DateTimeException if the day-of-month is invalid for the month-year
258 */
259 public static LocalDate of(int year, int month, int dayOfMonth) {
260 YEAR.checkValidValue(year);
261 MONTH_OF_YEAR.checkValidValue(month);
262 DAY_OF_MONTH.checkValidValue(dayOfMonth);
263 return create(year, Month.of(month), dayOfMonth);
264 }
265
266 //-----------------------------------------------------------------------
267 /**
268 * Obtains an instance of {@code LocalDate} from a year and day-of-year.
269 * <p>
270 * The day-of-year must be valid for the year, otherwise an exception will be thrown.
271 *
272 * @param year the year to represent, from MIN_YEAR to MAX_YEAR
273 * @param dayOfYear the day-of-year to represent, from 1 to 366
274 * @return the local date, not null
275 * @throws DateTimeException if the value of any field is out of range
276 * @throws DateTimeException if the day-of-year is invalid for the month-year
277 */
278 public static LocalDate ofYearDay(int year, int dayOfYear) {
279 YEAR.checkValidValue(year);
280 DAY_OF_YEAR.checkValidValue(dayOfYear);
281 boolean leap = ISOChrono.INSTANCE.isLeapYear(year);
282 if (dayOfYear == 366 && leap == false) {
283 throw new DateTimeException("Invalid date 'DayOfYear 366' as '" + year + "' is not a leap year");
284 }
285 Month moy = Month.of((dayOfYear - 1) / 31 + 1);
286 int monthEnd = moy.firstDayOfYear(leap) + moy.length(leap) - 1;
287 if (dayOfYear > monthEnd) {
288 moy = moy.plus(1);
289 }
290 int dom = dayOfYear - moy.firstDayOfYear(leap) + 1;
291 return create(year, moy, dom);
292 }
293
294 //-----------------------------------------------------------------------
295 /**
296 * Obtains an instance of {@code LocalDate} from the epoch day count.
297 * <p>
298 * The Epoch Day count is a simple incrementing count of days
299 * where day 0 is 1970-01-01. Negative numbers represent earlier days.
300 *
301 * @param epochDay the Epoch Day to convert, based on the epoch 1970-01-01
302 * @return the local date, not null
303 * @throws DateTimeException if the epoch days exceeds the supported date range
304 */
305 public static LocalDate ofEpochDay(long epochDay) {
306 long zeroDay = epochDay + DAYS_0000_TO_1970;
307 // find the march-based year
308 zeroDay -= 60; // adjust to 0000-03-01 so leap day is at end of four year cycle
309 long adjust = 0;
310 if (zeroDay < 0) {
311 // adjust negative years to positive for calculation
312 long adjustCycles = (zeroDay + 1) / DAYS_PER_CYCLE - 1;
313 adjust = adjustCycles * 400;
314 zeroDay += -adjustCycles * DAYS_PER_CYCLE;
315 }
316 long yearEst = (400 * zeroDay + 591) / DAYS_PER_CYCLE;
317 long doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
318 if (doyEst < 0) {
319 // fix estimate
320 yearEst--;
321 doyEst = zeroDay - (365 * yearEst + yearEst / 4 - yearEst / 100 + yearEst / 400);
322 }
323 yearEst += adjust; // reset any negative year
324 int marchDoy0 = (int) doyEst;
325
326 // convert march-based values back to january-based
327 int marchMonth0 = (marchDoy0 * 5 + 2) / 153;
328 int month = (marchMonth0 + 2) % 12 + 1;
329 int dom = marchDoy0 - (marchMonth0 * 306 + 5) / 10 + 1;
330 yearEst += marchMonth0 / 10;
331
332 // check year now we are certain it is correct
333 int year = YEAR.checkValidIntValue(yearEst);
334 return new LocalDate(year, month, dom);
335 }
336
337 //-----------------------------------------------------------------------
338 /**
339 * Obtains an instance of {@code LocalDate} from a temporal object.
340 * <p>
341 * A {@code TemporalAccessor} represents some form of date and time information.
342 * This factory converts the arbitrary temporal object to an instance of {@code LocalDate}.
343 * <p>
344 * The conversion extracts the {@link ChronoField#EPOCH_DAY EPOCH_DAY} field.
345 * <p>
346 * This method matches the signature of the functional interface {@link TemporalQuery}
347 * allowing it to be used as a query via method reference, {@code LocalDate::from}.
348 *
349 * @param temporal the temporal object to convert, not null
350 * @return the local date, not null
351 * @throws DateTimeException if unable to convert to a {@code LocalDate}
352 */
353 public static LocalDate from(TemporalAccessor temporal) {
354 if (temporal instanceof LocalDate) {
355 return (LocalDate) temporal;
356 } else if (temporal instanceof LocalDateTime) {
357 return ((LocalDateTime) temporal).getDate();
358 } else if (temporal instanceof ZonedDateTime) {
359 return ((ZonedDateTime) temporal).getDate();
360 }
361 // handle builder as a special case
362 if (temporal instanceof DateTimeBuilder) {
363 DateTimeBuilder builder = (DateTimeBuilder) temporal;
364 LocalDate date = builder.extract(LocalDate.class);
365 if (date != null) {
366 return date;
367 }
368 }
369 try {
370 return ofEpochDay(temporal.getLong(EPOCH_DAY));
371 } catch (DateTimeException ex) {
372 throw new DateTimeException("Unable to obtain LocalDate from TemporalAccessor: " + temporal.getClass(), ex);
373 }
374 }
375
376 //-----------------------------------------------------------------------
377 /**
378 * Obtains an instance of {@code LocalDate} from a text string such as {@code 2007-12-03}.
379 * <p>
380 * The string must represent a valid date and is parsed using
381 * {@link java.time.format.DateTimeFormatters#isoLocalDate()}.
382 *
383 * @param text the text to parse such as "2007-12-03", not null
384 * @return the parsed local date, not null
385 * @throws DateTimeParseException if the text cannot be parsed
386 */
387 public static LocalDate parse(CharSequence text) {
388 return parse(text, DateTimeFormatters.isoLocalDate());
389 }
390
391 /**
392 * Obtains an instance of {@code LocalDate} from a text string using a specific formatter.
393 * <p>
394 * The text is parsed using the formatter, returning a date.
395 *
396 * @param text the text to parse, not null
397 * @param formatter the formatter to use, not null
398 * @return the parsed local date, not null
399 * @throws DateTimeParseException if the text cannot be parsed
400 */
401 public static LocalDate parse(CharSequence text, DateTimeFormatter formatter) {
402 Objects.requireNonNull(formatter, "formatter");
403 return formatter.parse(text, LocalDate::from);
404 }
405
406 //-----------------------------------------------------------------------
407 /**
408 * Creates a local date from the year, month and day fields.
409 *
410 * @param year the year to represent, validated from MIN_YEAR to MAX_YEAR
411 * @param month the month-of-year to represent, validated not null
412 * @param dayOfMonth the day-of-month to represent, validated from 1 to 31
413 * @return the local date, not null
414 * @throws DateTimeException if the day-of-month is invalid for the month-year
415 */
416 private static LocalDate create(int year, Month month, int dayOfMonth) {
417 if (dayOfMonth > 28 && dayOfMonth > month.length(ISOChrono.INSTANCE.isLeapYear(year))) {
418 if (dayOfMonth == 29) {
419 throw new DateTimeException("Invalid date 'February 29' as '" + year + "' is not a leap year");
420 } else {
421 throw new DateTimeException("Invalid date '" + month.name() + " " + dayOfMonth + "'");
422 }
423 }
424 return new LocalDate(year, month.getValue(), dayOfMonth);
425 }
426
427 /**
428 * Resolves the date, resolving days past the end of month.
429 *
430 * @param year the year to represent, validated from MIN_YEAR to MAX_YEAR
431 * @param month the month-of-year to represent, validated from 1 to 12
432 * @param day the day-of-month to represent, validated from 1 to 31
433 * @return the resolved date, not null
434 */
435 private static LocalDate resolvePreviousValid(int year, int month, int day) {
436 switch (month) {
437 case 2:
438 day = Math.min(day, ISOChrono.INSTANCE.isLeapYear(year) ? 29 : 28);
439 break;
440 case 4:
441 case 6:
442 case 9:
443 case 11:
444 day = Math.min(day, 30);
445 break;
446 }
447 return LocalDate.of(year, month, day);
448 }
449
450 /**
451 * Constructor, previously validated.
452 *
453 * @param year the year to represent, from MIN_YEAR to MAX_YEAR
454 * @param month the month-of-year to represent, not null
455 * @param dayOfMonth the day-of-month to represent, valid for year-month, from 1 to 31
456 */
457 private LocalDate(int year, int month, int dayOfMonth) {
458 this.year = year;
459 this.month = (short) month;
460 this.day = (short) dayOfMonth;
461 }
462
463 //-----------------------------------------------------------------------
464 /**
465 * Checks if the specified field is supported.
466 * <p>
467 * This checks if this date can be queried for the specified field.
468 * If false, then calling the {@link #range(TemporalField) range} and
469 * {@link #get(TemporalField) get} methods will throw an exception.
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.
474 * The supported fields are:
475 * <ul>
476 * <li>{@code DAY_OF_WEEK}
477 * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
478 * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
479 * <li>{@code DAY_OF_MONTH}
480 * <li>{@code DAY_OF_YEAR}
481 * <li>{@code EPOCH_DAY}
482 * <li>{@code ALIGNED_WEEK_OF_MONTH}
483 * <li>{@code ALIGNED_WEEK_OF_YEAR}
484 * <li>{@code MONTH_OF_YEAR}
485 * <li>{@code EPOCH_MONTH}
486 * <li>{@code YEAR_OF_ERA}
487 * <li>{@code YEAR}
488 * <li>{@code ERA}
489 * </ul>
490 * All other {@code ChronoField} instances will return false.
491 * <p>
492 * If the field is not a {@code ChronoField}, then the result of this method
493 * is obtained by invoking {@code TemporalField.doIsSupported(TemporalAccessor)}
494 * passing {@code this} as the argument.
495 * Whether the field is supported is determined by the field.
496 *
497 * @param field the field to check, null returns false
498 * @return true if the field is supported on this date, false if not
499 */
500 @Override // override for Javadoc
501 public boolean isSupported(TemporalField field) {
502 return ChronoLocalDate.super.isSupported(field);
503 }
504
505 /**
506 * Gets the range of valid values for the specified field.
507 * <p>
508 * The range object expresses the minimum and maximum valid values for a field.
509 * This date is used to enhance the accuracy of the returned range.
510 * If it is not possible to return the range, because the field is not supported
511 * or for some other reason, an exception is thrown.
512 * <p>
513 * If the field is a {@link ChronoField} then the query is implemented here.
514 * The {@link #isSupported(TemporalField) supported fields} will return
515 * appropriate range instances.
516 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
517 * <p>
518 * If the field is not a {@code ChronoField}, then the result of this method
519 * is obtained by invoking {@code TemporalField.doRange(TemporalAccessor)}
520 * passing {@code this} as the argument.
521 * Whether the range can be obtained is determined by the field.
522 *
523 * @param field the field to query the range for, not null
524 * @return the range of valid values for the field, not null
525 * @throws DateTimeException if the range for the field cannot be obtained
526 */
527 @Override
528 public ValueRange range(TemporalField field) {
529 if (field instanceof ChronoField) {
530 ChronoField f = (ChronoField) field;
531 if (f.isDateField()) {
532 switch (f) {
533 case DAY_OF_MONTH: return ValueRange.of(1, lengthOfMonth());
534 case DAY_OF_YEAR: return ValueRange.of(1, lengthOfYear());
535 case ALIGNED_WEEK_OF_MONTH: return ValueRange.of(1, getMonth() == Month.FEBRUARY && isLeapYear() == false ? 4 : 5);
536 case YEAR_OF_ERA:
537 return (getYear() <= 0 ? ValueRange.of(1, Year.MAX_VALUE + 1) : ValueRange.of(1, Year.MAX_VALUE));
538 }
539 return field.range();
540 }
541 throw new DateTimeException("Unsupported field: " + field.getName());
542 }
543 return field.doRange(this);
544 }
545
546 /**
547 * Gets the value of the specified field from this date as an {@code int}.
548 * <p>
549 * This queries this date for the value for the specified field.
550 * The returned value will always be within the valid range of values for the field.
551 * If it is not possible to return the value, because the field is not supported
552 * or for some other reason, an exception is thrown.
553 * <p>
554 * If the field is a {@link ChronoField} then the query is implemented here.
555 * The {@link #isSupported(TemporalField) supported fields} will return valid
556 * values based on this date, except {@code EPOCH_DAY} and {@code EPOCH_MONTH}
557 * which are too large to fit in an {@code int} and throw a {@code DateTimeException}.
558 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
559 * <p>
560 * If the field is not a {@code ChronoField}, then the result of this method
561 * is obtained by invoking {@code TemporalField.doGet(TemporalAccessor)}
562 * passing {@code this} as the argument. Whether the value can be obtained,
563 * and what the value represents, is determined by the field.
564 *
565 * @param field the field to get, not null
566 * @return the value for the field
567 * @throws DateTimeException if a value for the field cannot be obtained
568 * @throws ArithmeticException if numeric overflow occurs
569 */
570 @Override // override for Javadoc and performance
571 public int get(TemporalField field) {
572 if (field instanceof ChronoField) {
573 return get0(field);
574 }
575 return ChronoLocalDate.super.get(field);
576 }
577
578 /**
579 * Gets the value of the specified field from this date as a {@code long}.
580 * <p>
581 * This queries this date for the value for the specified field.
582 * If it is not possible to return the value, because the field is not supported
583 * or for some other reason, an exception is thrown.
584 * <p>
585 * If the field is a {@link ChronoField} then the query is implemented here.
586 * The {@link #isSupported(TemporalField) supported fields} will return valid
587 * values based on this date.
588 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
589 * <p>
590 * If the field is not a {@code ChronoField}, then the result of this method
591 * is obtained by invoking {@code TemporalField.doGet(TemporalAccessor)}
592 * passing {@code this} as the argument. Whether the value can be obtained,
593 * and what the value represents, is determined by the field.
594 *
595 * @param field the field to get, not null
596 * @return the value for the field
597 * @throws DateTimeException if a value for the field cannot be obtained
598 * @throws ArithmeticException if numeric overflow occurs
599 */
600 @Override
601 public long getLong(TemporalField field) {
602 if (field instanceof ChronoField) {
603 if (field == EPOCH_DAY) {
604 return toEpochDay();
605 }
606 if (field == EPOCH_MONTH) {
607 return getEpochMonth();
608 }
609 return get0(field);
610 }
611 return field.doGet(this);
612 }
613
614 private int get0(TemporalField field) {
615 switch ((ChronoField) field) {
616 case DAY_OF_WEEK: return getDayOfWeek().getValue();
617 case ALIGNED_DAY_OF_WEEK_IN_MONTH: return ((day - 1) % 7) + 1;
618 case ALIGNED_DAY_OF_WEEK_IN_YEAR: return ((getDayOfYear() - 1) % 7) + 1;
619 case DAY_OF_MONTH: return day;
620 case DAY_OF_YEAR: return getDayOfYear();
621 case EPOCH_DAY: throw new DateTimeException("Field too large for an int: " + field);
622 case ALIGNED_WEEK_OF_MONTH: return ((day - 1) / 7) + 1;
623 case ALIGNED_WEEK_OF_YEAR: return ((getDayOfYear() - 1) / 7) + 1;
624 case MONTH_OF_YEAR: return month;
625 case EPOCH_MONTH: throw new DateTimeException("Field too large for an int: " + field);
626 case YEAR_OF_ERA: return (year >= 1 ? year : 1 - year);
627 case YEAR: return year;
628 case ERA: return (year >= 1 ? 1 : 0);
629 }
630 throw new DateTimeException("Unsupported field: " + field.getName());
631 }
632
633 private long getEpochMonth() {
634 return ((year - 1970) * 12L) + (month - 1);
635 }
636
637 //-----------------------------------------------------------------------
638 /**
639 * Gets the chronology of this date, which is the ISO calendar system.
640 * <p>
641 * The {@code Chrono} represents the calendar system in use.
642 * The ISO-8601 calendar system is the modern civil calendar system used today
643 * in most of the world. It is equivalent to the proleptic Gregorian calendar
644 * system, in which todays's rules for leap years are applied for all time.
645 *
646 * @return the ISO chronology, not null
647 */
648 @Override
649 public ISOChrono getChrono() {
650 return ISOChrono.INSTANCE;
651 }
652
653 /**
654 * Gets the era applicable at this date.
655 * <p>
656 * The official ISO-8601 standard does not define eras, however {@code ISOChrono} does.
657 * It defines two eras, 'CE' from year one onwards and 'BCE' from year zero backwards.
658 * Since dates before the Julian-Gregorian cutover are not in line with history,
659 * the cutover between 'BCE' and 'CE' is also not aligned with the commonly used
660 * eras, often referred to using 'BC' and 'AD'.
661 * <p>
662 * Users of this class should typically ignore this method as it exists primarily
663 * to fulfill the {@link ChronoLocalDate} contract where it is necessary to support
664 * the Japanese calendar system.
665 * <p>
666 * The returned era will be a singleton capable of being compared with the constants
667 * in {@link ISOChrono} using the {@code ==} operator.
668 *
669 * @return the {@code ISOChrono} era constant applicable at this date, not null
670 */
671 @Override // override for Javadoc
672 public Era<ISOChrono> getEra() {
673 return ChronoLocalDate.super.getEra();
674 }
675
676 /**
677 * Gets the year field.
678 * <p>
679 * This method returns the primitive {@code int} value for the year.
680 * <p>
681 * The year returned by this method is proleptic as per {@code get(YEAR)}.
682 * To obtain the year-of-era, use {@code get(YEAR_OF_ERA}.
683 *
684 * @return the year, from MIN_YEAR to MAX_YEAR
685 */
686 public int getYear() {
687 return year;
688 }
689
690 /**
691 * Gets the month-of-year field from 1 to 12.
692 * <p>
693 * This method returns the month as an {@code int} from 1 to 12.
694 * Application code is frequently clearer if the enum {@link Month}
695 * is used by calling {@link #getMonth()}.
696 *
697 * @return the month-of-year, from 1 to 12
698 * @see #getMonth()
699 */
700 public int getMonthValue() {
701 return month;
702 }
703
704 /**
705 * Gets the month-of-year field using the {@code Month} enum.
706 * <p>
707 * This method returns the enum {@link Month} for the month.
708 * This avoids confusion as to what {@code int} values mean.
709 * If you need access to the primitive {@code int} value then the enum
710 * provides the {@link Month#getValue() int value}.
711 *
712 * @return the month-of-year, not null
713 * @see #getMonthValue()
714 */
715 public Month getMonth() {
716 return Month.of(month);
717 }
718
719 /**
720 * Gets the day-of-month field.
721 * <p>
722 * This method returns the primitive {@code int} value for the day-of-month.
723 *
724 * @return the day-of-month, from 1 to 31
725 */
726 public int getDayOfMonth() {
727 return day;
728 }
729
730 /**
731 * Gets the day-of-year field.
732 * <p>
733 * This method returns the primitive {@code int} value for the day-of-year.
734 *
735 * @return the day-of-year, from 1 to 365, or 366 in a leap year
736 */
737 public int getDayOfYear() {
738 return getMonth().firstDayOfYear(isLeapYear()) + day - 1;
739 }
740
741 /**
742 * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
743 * <p>
744 * This method returns the enum {@link DayOfWeek} for the day-of-week.
745 * This avoids confusion as to what {@code int} values mean.
746 * If you need access to the primitive {@code int} value then the enum
747 * provides the {@link DayOfWeek#getValue() int value}.
748 * <p>
749 * Additional information can be obtained from the {@code DayOfWeek}.
750 * This includes textual names of the values.
751 *
752 * @return the day-of-week, not null
753 */
754 public DayOfWeek getDayOfWeek() {
755 int dow0 = (int)Math.floorMod(toEpochDay() + 3, 7);
756 return DayOfWeek.of(dow0 + 1);
757 }
758
759 //-----------------------------------------------------------------------
760 /**
761 * Checks if the year is a leap year, according to the ISO proleptic
762 * calendar system rules.
763 * <p>
764 * This method applies the current rules for leap years across the whole time-line.
765 * In general, a year is a leap year if it is divisible by four without
766 * remainder. However, years divisible by 100, are not leap years, with
767 * the exception of years divisible by 400 which are.
768 * <p>
769 * For example, 1904 is a leap year it is divisible by 4.
770 * 1900 was not a leap year as it is divisible by 100, however 2000 was a
771 * leap year as it is divisible by 400.
772 * <p>
773 * The calculation is proleptic - applying the same rules into the far future and far past.
774 * This is historically inaccurate, but is correct for the ISO-8601 standard.
775 *
776 * @return true if the year is leap, false otherwise
777 */
778 @Override // override for Javadoc and performance
779 public boolean isLeapYear() {
780 return ISOChrono.INSTANCE.isLeapYear(year);
781 }
782
783 /**
784 * Returns the length of the month represented by this date.
785 * <p>
786 * This returns the length of the month in days.
787 * For example, a date in January would return 31.
788 *
789 * @return the length of the month in days
790 */
791 @Override
792 public int lengthOfMonth() {
793 switch (month) {
794 case 2:
795 return (isLeapYear() ? 29 : 28);
796 case 4:
797 case 6:
798 case 9:
799 case 11:
800 return 30;
801 default:
802 return 31;
803 }
804 }
805
806 /**
807 * Returns the length of the year represented by this date.
808 * <p>
809 * This returns the length of the year in days, either 365 or 366.
810 *
811 * @return 366 if the year is leap, 365 otherwise
812 */
813 @Override // override for Javadoc and performance
814 public int lengthOfYear() {
815 return (isLeapYear() ? 366 : 365);
816 }
817
818 //-----------------------------------------------------------------------
819 /**
820 * Returns an adjusted copy of this date.
821 * <p>
822 * This returns a new {@code LocalDate}, based on this one, with the date adjusted.
823 * The adjustment takes place using the specified adjuster strategy object.
824 * Read the documentation of the adjuster to understand what adjustment will be made.
825 * <p>
826 * A simple adjuster might simply set the one of the fields, such as the year field.
827 * A more complex adjuster might set the date to the last day of the month.
828 * A selection of common adjustments is provided in {@link java.time.temporal.Adjusters}.
829 * These include finding the "last day of the month" and "next Wednesday".
830 * Key date-time classes also implement the {@code TemporalAdjuster} interface,
831 * such as {@link Month} and {@link java.time.temporal.MonthDay MonthDay}.
832 * The adjuster is responsible for handling special cases, such as the varying
833 * lengths of month and leap years.
834 * <p>
835 * For example this code returns a date on the last day of July:
836 * <pre>
837 * import static java.time.Month.*;
838 * import static java.time.temporal.Adjusters.*;
839 *
840 * result = localDate.with(JULY).with(lastDayOfMonth());
841 * </pre>
842 * <p>
843 * The result of this method is obtained by invoking the
844 * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
845 * specified adjuster passing {@code this} as the argument.
846 * <p>
847 * This instance is immutable and unaffected by this method call.
848 *
849 * @param adjuster the adjuster to use, not null
850 * @return a {@code LocalDate} based on {@code this} with the adjustment made, not null
851 * @throws DateTimeException if the adjustment cannot be made
852 * @throws ArithmeticException if numeric overflow occurs
853 */
854 @Override
855 public LocalDate with(TemporalAdjuster adjuster) {
856 // optimizations
857 if (adjuster instanceof LocalDate) {
858 return (LocalDate) adjuster;
859 }
860 return (LocalDate) adjuster.adjustInto(this);
861 }
862
863 /**
864 * Returns a copy of this date with the specified field set to a new value.
865 * <p>
866 * This returns a new {@code LocalDate}, based on this one, with the value
867 * for the specified field changed.
868 * This can be used to change any supported field, such as the year, month or day-of-month.
869 * If it is not possible to set the value, because the field is not supported or for
870 * some other reason, an exception is thrown.
871 * <p>
872 * In some cases, changing the specified field can cause the resulting date to become invalid,
873 * such as changing the month from 31st January to February would make the day-of-month invalid.
874 * In cases like this, the field is responsible for resolving the date. Typically it will choose
875 * the previous valid date, which would be the last valid day of February in this example.
876 * <p>
877 * If the field is a {@link ChronoField} then the adjustment is implemented here.
878 * The supported fields behave as follows:
879 * <ul>
880 * <li>{@code DAY_OF_WEEK} -
881 * Returns a {@code LocalDate} with the specified day-of-week.
882 * The date is adjusted up to 6 days forward or backward within the boundary
883 * of a Monday to Sunday week.
884 * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
885 * Returns a {@code LocalDate} with the specified aligned-day-of-week.
886 * The date is adjusted to the specified month-based aligned-day-of-week.
887 * Aligned weeks are counted such that the first week of a given month starts
888 * on the first day of that month.
889 * This may cause the date to be moved up to 6 days into the following month.
890 * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
891 * Returns a {@code LocalDate} with the specified aligned-day-of-week.
892 * The date is adjusted to the specified year-based aligned-day-of-week.
893 * Aligned weeks are counted such that the first week of a given year starts
894 * on the first day of that year.
895 * This may cause the date to be moved up to 6 days into the following year.
896 * <li>{@code DAY_OF_MONTH} -
897 * Returns a {@code LocalDate} with the specified day-of-month.
898 * The month and year will be unchanged. If the day-of-month is invalid for the
899 * year and month, then a {@code DateTimeException} is thrown.
900 * <li>{@code DAY_OF_YEAR} -
901 * Returns a {@code LocalDate} with the specified day-of-year.
902 * The year will be unchanged. If the day-of-year is invalid for the
903 * year, then a {@code DateTimeException} is thrown.
904 * <li>{@code EPOCH_DAY} -
905 * Returns a {@code LocalDate} with the specified epoch-day.
906 * This completely replaces the date and is equivalent to {@link #ofEpochDay(long)}.
907 * <li>{@code ALIGNED_WEEK_OF_MONTH} -
908 * Returns a {@code LocalDate} with the specified aligned-week-of-month.
909 * Aligned weeks are counted such that the first week of a given month starts
910 * on the first day of that month.
911 * This adjustment moves the date in whole week chunks to match the specified week.
912 * The result will have the same day-of-week as this date.
913 * This may cause the date to be moved into the following month.
914 * <li>{@code ALIGNED_WEEK_OF_YEAR} -
915 * Returns a {@code LocalDate} with the specified aligned-week-of-year.
916 * Aligned weeks are counted such that the first week of a given year starts
917 * on the first day of that year.
918 * This adjustment moves the date in whole week chunks to match the specified week.
919 * The result will have the same day-of-week as this date.
920 * This may cause the date to be moved into the following year.
921 * <li>{@code MONTH_OF_YEAR} -
922 * Returns a {@code LocalDate} with the specified month-of-year.
923 * The year will be unchanged. The day-of-month will also be unchanged,
924 * unless it would be invalid for the new month and year. In that case, the
925 * day-of-month is adjusted to the maximum valid value for the new month and year.
926 * <li>{@code EPOCH_MONTH} -
927 * Returns a {@code LocalDate} with the specified epoch-month.
928 * The day-of-month will be unchanged, unless it would be invalid for the new month
929 * and year. In that case, the day-of-month is adjusted to the maximum valid value
930 * for the new month and year.
931 * <li>{@code YEAR_OF_ERA} -
932 * Returns a {@code LocalDate} with the specified year-of-era.
933 * The era and month will be unchanged. The day-of-month will also be unchanged,
934 * unless it would be invalid for the new month and year. In that case, the
935 * day-of-month is adjusted to the maximum valid value for the new month and year.
936 * <li>{@code YEAR} -
937 * Returns a {@code LocalDate} with the specified year.
938 * The month will be unchanged. The day-of-month will also be unchanged,
939 * unless it would be invalid for the new month and year. In that case, the
940 * day-of-month is adjusted to the maximum valid value for the new month and year.
941 * <li>{@code ERA} -
942 * Returns a {@code LocalDate} with the specified era.
943 * The year-of-era and month will be unchanged. The day-of-month will also be unchanged,
944 * unless it would be invalid for the new month and year. In that case, the
945 * day-of-month is adjusted to the maximum valid value for the new month and year.
946 * </ul>
947 * <p>
948 * In all cases, if the new value is outside the valid range of values for the field
949 * then a {@code DateTimeException} will be thrown.
950 * <p>
951 * All other {@code ChronoField} instances will throw a {@code DateTimeException}.
952 * <p>
953 * If the field is not a {@code ChronoField}, then the result of this method
954 * is obtained by invoking {@code TemporalField.doWith(Temporal, long)}
955 * passing {@code this} as the argument. In this case, the field determines
956 * whether and how to adjust the instant.
957 * <p>
958 * This instance is immutable and unaffected by this method call.
959 *
960 * @param field the field to set in the result, not null
961 * @param newValue the new value of the field in the result
962 * @return a {@code LocalDate} based on {@code this} with the specified field set, not null
963 * @throws DateTimeException if the field cannot be set
964 * @throws ArithmeticException if numeric overflow occurs
965 */
966 @Override
967 public LocalDate with(TemporalField field, long newValue) {
968 if (field instanceof ChronoField) {
969 ChronoField f = (ChronoField) field;
970 f.checkValidValue(newValue);
971 switch (f) {
972 case DAY_OF_WEEK: return plusDays(newValue - getDayOfWeek().getValue());
973 case ALIGNED_DAY_OF_WEEK_IN_MONTH: return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_MONTH));
974 case ALIGNED_DAY_OF_WEEK_IN_YEAR: return plusDays(newValue - getLong(ALIGNED_DAY_OF_WEEK_IN_YEAR));
975 case DAY_OF_MONTH: return withDayOfMonth((int) newValue);
976 case DAY_OF_YEAR: return withDayOfYear((int) newValue);
977 case EPOCH_DAY: return LocalDate.ofEpochDay(newValue);
978 case ALIGNED_WEEK_OF_MONTH: return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_MONTH));
979 case ALIGNED_WEEK_OF_YEAR: return plusWeeks(newValue - getLong(ALIGNED_WEEK_OF_YEAR));
980 case MONTH_OF_YEAR: return withMonth((int) newValue);
981 case EPOCH_MONTH: return plusMonths(newValue - getLong(EPOCH_MONTH));
982 case YEAR_OF_ERA: return withYear((int) (year >= 1 ? newValue : 1 - newValue));
983 case YEAR: return withYear((int) newValue);
984 case ERA: return (getLong(ERA) == newValue ? this : withYear(1 - year));
985 }
986 throw new DateTimeException("Unsupported field: " + field.getName());
987 }
988 return field.doWith(this, newValue);
989 }
990
991 //-----------------------------------------------------------------------
992 /**
993 * Returns a copy of this date with the year altered.
994 * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
995 * <p>
996 * This instance is immutable and unaffected by this method call.
997 *
998 * @param year the year to set in the result, from MIN_YEAR to MAX_YEAR
999 * @return a {@code LocalDate} based on this date with the requested year, not null
1000 * @throws DateTimeException if the year value is invalid
1001 */
1002 public LocalDate withYear(int year) {
1003 if (this.year == year) {
1004 return this;
1005 }
1006 YEAR.checkValidValue(year);
1007 return resolvePreviousValid(year, month, day);
1008 }
1009
1010 /**
1011 * Returns a copy of this date with the month-of-year altered.
1012 * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
1013 * <p>
1014 * This instance is immutable and unaffected by this method call.
1015 *
1016 * @param month the month-of-year to set in the result, from 1 (January) to 12 (December)
1017 * @return a {@code LocalDate} based on this date with the requested month, not null
1018 * @throws DateTimeException if the month-of-year value is invalid
1019 */
1020 public LocalDate withMonth(int month) {
1021 if (this.month == month) {
1022 return this;
1023 }
1024 MONTH_OF_YEAR.checkValidValue(month);
1025 return resolvePreviousValid(year, month, day);
1026 }
1027
1028 /**
1029 * Returns a copy of this date with the day-of-month altered.
1030 * If the resulting date is invalid, an exception is thrown.
1031 * <p>
1032 * This instance is immutable and unaffected by this method call.
1033 *
1034 * @param dayOfMonth the day-of-month to set in the result, from 1 to 28-31
1035 * @return a {@code LocalDate} based on this date with the requested day, not null
1036 * @throws DateTimeException if the day-of-month value is invalid
1037 * @throws DateTimeException if the day-of-month is invalid for the month-year
1038 */
1039 public LocalDate withDayOfMonth(int dayOfMonth) {
1040 if (this.day == dayOfMonth) {
1041 return this;
1042 }
1043 return of(year, month, dayOfMonth);
1044 }
1045
1046 /**
1047 * Returns a copy of this date with the day-of-year altered.
1048 * If the resulting date is invalid, an exception is thrown.
1049 * <p>
1050 * This instance is immutable and unaffected by this method call.
1051 *
1052 * @param dayOfYear the day-of-year to set in the result, from 1 to 365-366
1053 * @return a {@code LocalDate} based on this date with the requested day, not null
1054 * @throws DateTimeException if the day-of-year value is invalid
1055 * @throws DateTimeException if the day-of-year is invalid for the year
1056 */
1057 public LocalDate withDayOfYear(int dayOfYear) {
1058 if (this.getDayOfYear() == dayOfYear) {
1059 return this;
1060 }
1061 return ofYearDay(year, dayOfYear);
1062 }
1063
1064 //-----------------------------------------------------------------------
1065 /**
1066 * Returns a copy of this date with the specified period added.
1067 * <p>
1068 * This method returns a new date based on this date with the specified period added.
1069 * The adder is typically {@link Period} but may be any other type implementing
1070 * the {@link TemporalAdder} interface.
1071 * The calculation is delegated to the specified adjuster, which typically calls
1072 * back to {@link #plus(long, TemporalUnit)}.
1073 * <p>
1074 * This instance is immutable and unaffected by this method call.
1075 *
1076 * @param adder the adder to use, not null
1077 * @return a {@code LocalDate} based on this date with the addition made, not null
1078 * @throws DateTimeException if the addition cannot be made
1079 * @throws ArithmeticException if numeric overflow occurs
1080 */
1081 @Override
1082 public LocalDate plus(TemporalAdder adder) {
1083 return (LocalDate) adder.addTo(this);
1084 }
1085
1086 /**
1087 * Returns a copy of this date with the specified period added.
1088 * <p>
1089 * This method returns a new date based on this date with the specified period added.
1090 * This can be used to add any period that is defined by a unit, for example to add years, months or days.
1091 * The unit is responsible for the details of the calculation, including the resolution
1092 * of any edge cases in the calculation.
1093 * <p>
1094 * This instance is immutable and unaffected by this method call.
1095 *
1096 * @param amountToAdd the amount of the unit to add to the result, may be negative
1097 * @param unit the unit of the period to add, not null
1098 * @return a {@code LocalDate} based on this date with the specified period added, not null
1099 * @throws DateTimeException if the unit cannot be added to this type
1100 */
1101 @Override
1102 public LocalDate plus(long amountToAdd, TemporalUnit unit) {
1103 if (unit instanceof ChronoUnit) {
1104 ChronoUnit f = (ChronoUnit) unit;
1105 switch (f) {
1106 case DAYS: return plusDays(amountToAdd);
1107 case WEEKS: return plusWeeks(amountToAdd);
1108 case MONTHS: return plusMonths(amountToAdd);
1109 case YEARS: return plusYears(amountToAdd);
1110 case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10));
1111 case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100));
1112 case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000));
1113 case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd));
1114 }
1115 throw new DateTimeException("Unsupported unit: " + unit.getName());
1116 }
1117 return unit.doPlus(this, amountToAdd);
1118 }
1119
1120 //-----------------------------------------------------------------------
1121 /**
1122 * Returns a copy of this {@code LocalDate} with the specified period in years added.
1123 * <p>
1124 * This method adds the specified amount to the years field in three steps:
1125 * <ol>
1126 * <li>Add the input years to the year field</li>
1127 * <li>Check if the resulting date would be invalid</li>
1128 * <li>Adjust the day-of-month to the last valid day if necessary</li>
1129 * </ol>
1130 * <p>
1131 * For example, 2008-02-29 (leap year) plus one year would result in the
1132 * invalid date 2009-02-29 (standard year). Instead of returning an invalid
1133 * result, the last valid day of the month, 2009-02-28, is selected instead.
1134 * <p>
1135 * This instance is immutable and unaffected by this method call.
1136 *
1137 * @param yearsToAdd the years to add, may be negative
1138 * @return a {@code LocalDate} based on this date with the years added, not null
1139 * @throws DateTimeException if the result exceeds the supported date range
1140 */
1141 public LocalDate plusYears(long yearsToAdd) {
1142 if (yearsToAdd == 0) {
1143 return this;
1144 }
1145 int newYear = YEAR.checkValidIntValue(year + yearsToAdd); // safe overflow
1146 return resolvePreviousValid(newYear, month, day);
1147 }
1148
1149 /**
1150 * Returns a copy of this {@code LocalDate} with the specified period in months added.
1151 * <p>
1152 * This method adds the specified amount to the months field in three steps:
1153 * <ol>
1154 * <li>Add the input months to the month-of-year field</li>
1155 * <li>Check if the resulting date would be invalid</li>
1156 * <li>Adjust the day-of-month to the last valid day if necessary</li>
1157 * </ol>
1158 * <p>
1159 * For example, 2007-03-31 plus one month would result in the invalid date
1160 * 2007-04-31. Instead of returning an invalid result, the last valid day
1161 * of the month, 2007-04-30, is selected instead.
1162 * <p>
1163 * This instance is immutable and unaffected by this method call.
1164 *
1165 * @param monthsToAdd the months to add, may be negative
1166 * @return a {@code LocalDate} based on this date with the months added, not null
1167 * @throws DateTimeException if the result exceeds the supported date range
1168 */
1169 public LocalDate plusMonths(long monthsToAdd) {
1170 if (monthsToAdd == 0) {
1171 return this;
1172 }
1173 long monthCount = year * 12L + (month - 1);
1174 long calcMonths = monthCount + monthsToAdd; // safe overflow
1175 int newYear = YEAR.checkValidIntValue(Math.floorDiv(calcMonths, 12));
1176 int newMonth = (int)Math.floorMod(calcMonths, 12) + 1;
1177 return resolvePreviousValid(newYear, newMonth, day);
1178 }
1179
1180 /**
1181 * Returns a copy of this {@code LocalDate} with the specified period in weeks added.
1182 * <p>
1183 * This method adds the specified amount in weeks to the days field incrementing
1184 * the month and year fields as necessary to ensure the result remains valid.
1185 * The result is only invalid if the maximum/minimum year is exceeded.
1186 * <p>
1187 * For example, 2008-12-31 plus one week would result in 2009-01-07.
1188 * <p>
1189 * This instance is immutable and unaffected by this method call.
1190 *
1191 * @param weeksToAdd the weeks to add, may be negative
1192 * @return a {@code LocalDate} based on this date with the weeks added, not null
1193 * @throws DateTimeException if the result exceeds the supported date range
1194 */
1195 public LocalDate plusWeeks(long weeksToAdd) {
1196 return plusDays(Math.multiplyExact(weeksToAdd, 7));
1197 }
1198
1199 /**
1200 * Returns a copy of this {@code LocalDate} with the specified number of days added.
1201 * <p>
1202 * This method adds the specified amount to the days field incrementing the
1203 * month and year fields as necessary to ensure the result remains valid.
1204 * The result is only invalid if the maximum/minimum year is exceeded.
1205 * <p>
1206 * For example, 2008-12-31 plus one day would result in 2009-01-01.
1207 * <p>
1208 * This instance is immutable and unaffected by this method call.
1209 *
1210 * @param daysToAdd the days to add, may be negative
1211 * @return a {@code LocalDate} based on this date with the days added, not null
1212 * @throws DateTimeException if the result exceeds the supported date range
1213 */
1214 public LocalDate plusDays(long daysToAdd) {
1215 if (daysToAdd == 0) {
1216 return this;
1217 }
1218 long mjDay = Math.addExact(toEpochDay(), daysToAdd);
1219 return LocalDate.ofEpochDay(mjDay);
1220 }
1221
1222 //-----------------------------------------------------------------------
1223 /**
1224 * Returns a copy of this date with the specified period subtracted.
1225 * <p>
1226 * This method returns a new date based on this date with the specified period subtracted.
1227 * The subtractor is typically {@link Period} but may be any other type implementing
1228 * the {@link TemporalSubtractor} interface.
1229 * The calculation is delegated to the specified adjuster, which typically calls
1230 * back to {@link #minus(long, TemporalUnit)}.
1231 * <p>
1232 * This instance is immutable and unaffected by this method call.
1233 *
1234 * @param subtractor the subtractor to use, not null
1235 * @return a {@code LocalDate} based on this date with the subtraction made, not null
1236 * @throws DateTimeException if the subtraction cannot be made
1237 * @throws ArithmeticException if numeric overflow occurs
1238 */
1239 @Override
1240 public LocalDate minus(TemporalSubtractor subtractor) {
1241 return (LocalDate) subtractor.subtractFrom(this);
1242 }
1243
1244 /**
1245 * Returns a copy of this date with the specified period subtracted.
1246 * <p>
1247 * This method returns a new date based on this date with the specified period subtracted.
1248 * This can be used to subtract any period that is defined by a unit, for example to subtract years, months or days.
1249 * The unit is responsible for the details of the calculation, including the resolution
1250 * of any edge cases in the calculation.
1251 * <p>
1252 * This instance is immutable and unaffected by this method call.
1253 *
1254 * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
1255 * @param unit the unit of the period to subtract, not null
1256 * @return a {@code LocalDate} based on this date with the specified period subtracted, not null
1257 * @throws DateTimeException if the unit cannot be added to this type
1258 */
1259 @Override
1260 public LocalDate minus(long amountToSubtract, TemporalUnit unit) {
1261 return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
1262 }
1263
1264 //-----------------------------------------------------------------------
1265 /**
1266 * Returns a copy of this {@code LocalDate} with the specified period in years subtracted.
1267 * <p>
1268 * This method subtracts the specified amount from the years field in three steps:
1269 * <ol>
1270 * <li>Subtract the input years to the year field</li>
1271 * <li>Check if the resulting date would be invalid</li>
1272 * <li>Adjust the day-of-month to the last valid day if necessary</li>
1273 * </ol>
1274 * <p>
1275 * For example, 2008-02-29 (leap year) minus one year would result in the
1276 * invalid date 2007-02-29 (standard year). Instead of returning an invalid
1277 * result, the last valid day of the month, 2007-02-28, is selected instead.
1278 * <p>
1279 * This instance is immutable and unaffected by this method call.
1280 *
1281 * @param yearsToSubtract the years to subtract, may be negative
1282 * @return a {@code LocalDate} based on this date with the years subtracted, not null
1283 * @throws DateTimeException if the result exceeds the supported date range
1284 */
1285 public LocalDate minusYears(long yearsToSubtract) {
1286 return (yearsToSubtract == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-yearsToSubtract));
1287 }
1288
1289 /**
1290 * Returns a copy of this {@code LocalDate} with the specified period in months subtracted.
1291 * <p>
1292 * This method subtracts the specified amount from the months field in three steps:
1293 * <ol>
1294 * <li>Subtract the input months to the month-of-year field</li>
1295 * <li>Check if the resulting date would be invalid</li>
1296 * <li>Adjust the day-of-month to the last valid day if necessary</li>
1297 * </ol>
1298 * <p>
1299 * For example, 2007-03-31 minus one month would result in the invalid date
1300 * 2007-02-31. Instead of returning an invalid result, the last valid day
1301 * of the month, 2007-02-28, is selected instead.
1302 * <p>
1303 * This instance is immutable and unaffected by this method call.
1304 *
1305 * @param monthsToSubtract the months to subtract, may be negative
1306 * @return a {@code LocalDate} based on this date with the months subtracted, not null
1307 * @throws DateTimeException if the result exceeds the supported date range
1308 */
1309 public LocalDate minusMonths(long monthsToSubtract) {
1310 return (monthsToSubtract == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-monthsToSubtract));
1311 }
1312
1313 /**
1314 * Returns a copy of this {@code LocalDate} with the specified period in weeks subtracted.
1315 * <p>
1316 * This method subtracts the specified amount in weeks from the days field decrementing
1317 * the month and year fields as necessary to ensure the result remains valid.
1318 * The result is only invalid if the maximum/minimum year is exceeded.
1319 * <p>
1320 * For example, 2009-01-07 minus one week would result in 2008-12-31.
1321 * <p>
1322 * This instance is immutable and unaffected by this method call.
1323 *
1324 * @param weeksToSubtract the weeks to subtract, may be negative
1325 * @return a {@code LocalDate} based on this date with the weeks subtracted, not null
1326 * @throws DateTimeException if the result exceeds the supported date range
1327 */
1328 public LocalDate minusWeeks(long weeksToSubtract) {
1329 return (weeksToSubtract == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1) : plusWeeks(-weeksToSubtract));
1330 }
1331
1332 /**
1333 * Returns a copy of this {@code LocalDate} with the specified number of days subtracted.
1334 * <p>
1335 * This method subtracts the specified amount from the days field decrementing the
1336 * month and year fields as necessary to ensure the result remains valid.
1337 * The result is only invalid if the maximum/minimum year is exceeded.
1338 * <p>
1339 * For example, 2009-01-01 minus one day would result in 2008-12-31.
1340 * <p>
1341 * This instance is immutable and unaffected by this method call.
1342 *
1343 * @param daysToSubtract the days to subtract, may be negative
1344 * @return a {@code LocalDate} based on this date with the days subtracted, not null
1345 * @throws DateTimeException if the result exceeds the supported date range
1346 */
1347 public LocalDate minusDays(long daysToSubtract) {
1348 return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract));
1349 }
1350
1351 //-----------------------------------------------------------------------
1352 /**
1353 * Queries this date using the specified query.
1354 * <p>
1355 * This queries this date using the specified query strategy object.
1356 * The {@code TemporalQuery} object defines the logic to be used to
1357 * obtain the result. Read the documentation of the query to understand
1358 * what the result of this method will be.
1359 * <p>
1360 * The result of this method is obtained by invoking the
1361 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
1362 * specified query passing {@code this} as the argument.
1363 *
1364 * @param <R> the type of the result
1365 * @param query the query to invoke, not null
1366 * @return the query result, null may be returned (defined by the query)
1367 * @throws DateTimeException if unable to query (defined by the query)
1368 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
1369 */
1370 @Override // override for Javadoc
1371 public <R> R query(TemporalQuery<R> query) {
1372 return ChronoLocalDate.super.query(query);
1373 }
1374
1375 /**
1376 * Adjusts the specified temporal object to have the same date as this object.
1377 * <p>
1378 * This returns a temporal object of the same observable type as the input
1379 * with the date changed to be the same as this.
1380 * <p>
1381 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
1382 * passing {@link ChronoField#EPOCH_DAY} as the field.
1383 * <p>
1384 * In most cases, it is clearer to reverse the calling pattern by using
1385 * {@link Temporal#with(TemporalAdjuster)}:
1386 * <pre>
1387 * // these two lines are equivalent, but the second approach is recommended
1388 * temporal = thisLocalDate.adjustInto(temporal);
1389 * temporal = temporal.with(thisLocalDate);
1390 * </pre>
1391 * <p>
1392 * This instance is immutable and unaffected by this method call.
1393 *
1394 * @param temporal the target object to be adjusted, not null
1395 * @return the adjusted object, not null
1396 * @throws DateTimeException if unable to make the adjustment
1397 * @throws ArithmeticException if numeric overflow occurs
1398 */
1399 @Override // override for Javadoc
1400 public Temporal adjustInto(Temporal temporal) {
1401 return ChronoLocalDate.super.adjustInto(temporal);
1402 }
1403
1404 /**
1405 * Calculates the period between this date and another date in
1406 * terms of the specified unit.
1407 * <p>
1408 * This calculates the period between two dates in terms of a single unit.
1409 * The start and end points are {@code this} and the specified date.
1410 * The result will be negative if the end is before the start.
1411 * The {@code Temporal} passed to this method must be a {@code LocalDate}.
1412 * For example, the period in days between two dates can be calculated
1413 * using {@code startDate.periodUntil(endDate, DAYS)}.
1414 * <p>
1415 * The calculation returns a whole number, representing the number of
1416 * complete units between the two dates.
1417 * For example, the period in months between 2012-06-15 and 2012-08-14
1418 * will only be one month as it is one day short of two months.
1419 * <p>
1420 * This method operates in association with {@link TemporalUnit#between}.
1421 * The result of this method is a {@code long} representing the amount of
1422 * the specified unit. By contrast, the result of {@code between} is an
1423 * object that can be used directly in addition/subtraction:
1424 * <pre>
1425 * long period = start.periodUntil(end, MONTHS); // this method
1426 * dateTime.plus(MONTHS.between(start, end)); // use in plus/minus
1427 * </pre>
1428 * <p>
1429 * The calculation is implemented in this method for {@link ChronoUnit}.
1430 * The units {@code DAYS}, {@code WEEKS}, {@code MONTHS}, {@code YEARS},
1431 * {@code DECADES}, {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS}
1432 * are supported. Other {@code ChronoUnit} values will throw an exception.
1433 * <p>
1434 * If the unit is not a {@code ChronoUnit}, then the result of this method
1435 * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
1436 * passing {@code this} as the first argument and the input temporal as
1437 * the second argument.
1438 * <p>
1439 * This instance is immutable and unaffected by this method call.
1440 *
1441 * @param endDate the end date, which must be a {@code LocalDate}, not null
1442 * @param unit the unit to measure the period in, not null
1443 * @return the amount of the period between this date and the end date
1444 * @throws DateTimeException if the period cannot be calculated
1445 * @throws ArithmeticException if numeric overflow occurs
1446 */
1447 @Override
1448 public long periodUntil(Temporal endDate, TemporalUnit unit) {
1449 if (endDate instanceof LocalDate == false) {
1450 Objects.requireNonNull(endDate, "endDate");
1451 throw new DateTimeException("Unable to calculate period between objects of two different types");
1452 }
1453 LocalDate end = (LocalDate) endDate;
1454 if (unit instanceof ChronoUnit) {
1455 switch ((ChronoUnit) unit) {
1456 case DAYS: return daysUntil(end);
1457 case WEEKS: return daysUntil(end) / 7;
1458 case MONTHS: return monthsUntil(end);
1459 case YEARS: return monthsUntil(end) / 12;
1460 case DECADES: return monthsUntil(end) / 120;
1461 case CENTURIES: return monthsUntil(end) / 1200;
1462 case MILLENNIA: return monthsUntil(end) / 12000;
1463 case ERAS: return end.getLong(ERA) - getLong(ERA);
1464 }
1465 throw new DateTimeException("Unsupported unit: " + unit.getName());
1466 }
1467 return unit.between(this, endDate).getAmount();
1468 }
1469
1470 long daysUntil(LocalDate end) {
1471 return end.toEpochDay() - toEpochDay(); // no overflow
1472 }
1473
1474 private long monthsUntil(LocalDate end) {
1475 long packed1 = getEpochMonth() * 32L + getDayOfMonth(); // no overflow
1476 long packed2 = end.getEpochMonth() * 32L + end.getDayOfMonth(); // no overflow
1477 return (packed2 - packed1) / 32;
1478 }
1479
1480 //-----------------------------------------------------------------------
1481 /**
1482 * Returns a local date-time formed from this date at the specified time.
1483 * <p>
1484 * This combines this date with the specified time to form a {@code LocalDateTime}.
1485 * All possible combinations of date and time are valid.
1486 * <p>
1487 * This instance is immutable and unaffected by this method call.
1488 *
1489 * @param time the time to combine with, not null
1490 * @return the local date-time formed from this date and the specified time, not null
1491 */
1492 @Override
1493 public LocalDateTime atTime(LocalTime time) {
1494 return LocalDateTime.of(this, time);
1495 }
1496
1497 /**
1498 * Returns a local date-time formed from this date at the specified time.
1499 * <p>
1500 * This combines this date with the specified time to form a {@code LocalDateTime}.
1501 * The individual time fields must be within their valid range.
1502 * All possible combinations of date and time are valid.
1503 * <p>
1504 * This instance is immutable and unaffected by this method call.
1505 *
1506 * @param hour the hour-of-day to use, from 0 to 23
1507 * @param minute the minute-of-hour to use, from 0 to 59
1508 * @return the local date-time formed from this date and the specified time, not null
1509 * @throws DateTimeException if the value of any field is out of range
1510 */
1511 public LocalDateTime atTime(int hour, int minute) {
1512 return atTime(LocalTime.of(hour, minute));
1513 }
1514
1515 /**
1516 * Returns a local date-time formed from this date at the specified time.
1517 * <p>
1518 * This combines this date with the specified time to form a {@code LocalDateTime}.
1519 * The individual time fields must be within their valid range.
1520 * All possible combinations of date and time are valid.
1521 * <p>
1522 * This instance is immutable and unaffected by this method call.
1523 *
1524 * @param hour the hour-of-day to use, from 0 to 23
1525 * @param minute the minute-of-hour to use, from 0 to 59
1526 * @param second the second-of-minute to represent, from 0 to 59
1527 * @return the local date-time formed from this date and the specified time, not null
1528 * @throws DateTimeException if the value of any field is out of range
1529 */
1530 public LocalDateTime atTime(int hour, int minute, int second) {
1531 return atTime(LocalTime.of(hour, minute, second));
1532 }
1533
1534 /**
1535 * Returns a local date-time formed from this date at the specified time.
1536 * <p>
1537 * This combines this date with the specified time to form a {@code LocalDateTime}.
1538 * The individual time fields must be within their valid range.
1539 * All possible combinations of date and time are valid.
1540 * <p>
1541 * This instance is immutable and unaffected by this method call.
1542 *
1543 * @param hour the hour-of-day to use, from 0 to 23
1544 * @param minute the minute-of-hour to use, from 0 to 59
1545 * @param second the second-of-minute to represent, from 0 to 59
1546 * @param nanoOfSecond the nano-of-second to represent, from 0 to 999,999,999
1547 * @return the local date-time formed from this date and the specified time, not null
1548 * @throws DateTimeException if the value of any field is out of range
1549 */
1550 public LocalDateTime atTime(int hour, int minute, int second, int nanoOfSecond) {
1551 return atTime(LocalTime.of(hour, minute, second, nanoOfSecond));
1552 }
1553
1554 /**
1555 * Returns an offset date formed from this date and the specified offset.
1556 * <p>
1557 * This combines this date with the specified offset to form an {@code OffsetDate}.
1558 * All possible combinations of date and offset are valid.
1559 * <p>
1560 * This instance is immutable and unaffected by this method call.
1561 *
1562 * @param offset the offset to combine with, not null
1563 * @return the offset date formed from this date and the specified offset, not null
1564 */
1565 public OffsetDate atOffset(ZoneOffset offset) {
1566 return OffsetDate.of(this, offset);
1567 }
1568
1569 /**
1570 * Returns a zoned date-time from this date at the earliest valid time according
1571 * to the rules in the time-zone.
1572 * <p>
1573 * Time-zone rules, such as daylight savings, mean that not every local date-time
1574 * is valid for the specified zone, thus the local date-time may not be midnight.
1575 * <p>
1576 * In most cases, there is only one valid offset for a local date-time.
1577 * In the case of an overlap, there are two valid offsets, and the earlier one is used,
1578 * corresponding to the first occurrence of midnight on the date.
1579 * In the case of a gap, the zoned date-time will represent the instant just after the gap.
1580 * <p>
1581 * If the zone ID is a {@link ZoneOffset}, then the result always has a time of midnight.
1582 * <p>
1583 * To convert to a specific time in a given time-zone call {@link #atTime(LocalTime)}
1584 * followed by {@link LocalDateTime#atZone(ZoneId)}.
1585 * <p>
1586 * This instance is immutable and unaffected by this method call.
1587 *
1588 * @param zone the zone ID to use, not null
1589 * @return the zoned date-time formed from this date and the earliest valid time for the zone, not null
1590 */
1591 public ZonedDateTime atStartOfDay(ZoneId zone) {
1592 Objects.requireNonNull(zone, "zone");
1593 // need to handle case where there is a gap from 11:30 to 00:30
1594 // standard ZDT factory would result in 01:00 rather than 00:30
1595 LocalDateTime ldt = atTime(LocalTime.MIDNIGHT);
1596 if (zone instanceof ZoneOffset == false) {
1597 ZoneRules rules = zone.getRules();
1598 ZoneOffsetTransition trans = rules.getTransition(ldt);
1599 if (trans != null && trans.isGap()) {
1600 ldt = trans.getDateTimeAfter();
1601 }
1602 }
1603 return ZonedDateTime.of(ldt, zone);
1604 }
1605
1606 //-----------------------------------------------------------------------
1607 @Override
1608 public long toEpochDay() {
1609 long y = year;
1610 long m = month;
1611 long total = 0;
1612 total += 365 * y;
1613 if (y >= 0) {
1614 total += (y + 3) / 4 - (y + 99) / 100 + (y + 399) / 400;
1615 } else {
1616 total -= y / -4 - y / -100 + y / -400;
1617 }
1618 total += ((367 * m - 362) / 12);
1619 total += day - 1;
1620 if (m > 2) {
1621 total--;
1622 if (isLeapYear() == false) {
1623 total--;
1624 }
1625 }
1626 return total - DAYS_0000_TO_1970;
1627 }
1628
1629 //-----------------------------------------------------------------------
1630 /**
1631 * Compares this date to another date.
1632 * <p>
1633 * The comparison is primarily based on the date, from earliest to latest.
1634 * It is "consistent with equals", as defined by {@link Comparable}.
1635 * <p>
1636 * If all the dates being compared are instances of {@code LocalDate},
1637 * then the comparison will be entirely based on the date.
1638 * If some dates being compared are in different chronologies, then the
1639 * chronology is also considered, see {@link java.time.temporal.ChronoLocalDate#compareTo}.
1640 *
1641 * @param other the other date to compare to, not null
1642 * @return the comparator value, negative if less, positive if greater
1643 */
1644 @Override // override for Javadoc and performance
1645 public int compareTo(ChronoLocalDate<?> other) {
1646 if (other instanceof LocalDate) {
1647 return compareTo0((LocalDate) other);
1648 }
1649 return ChronoLocalDate.super.compareTo(other);
1650 }
1651
1652 int compareTo0(LocalDate otherDate) {
1653 int cmp = (year - otherDate.year);
1654 if (cmp == 0) {
1655 cmp = (month - otherDate.month);
1656 if (cmp == 0) {
1657 cmp = (day - otherDate.day);
1658 }
1659 }
1660 return cmp;
1661 }
1662
1663 /**
1664 * Checks if this date is after the specified date.
1665 * <p>
1666 * This checks to see if this date represents a point on the
1667 * local time-line after the other date.
1668 * <pre>
1669 * LocalDate a = LocalDate.of(2012, 6, 30);
1670 * LocalDate b = LocalDate.of(2012, 7, 1);
1671 * a.isAfter(b) == false
1672 * a.isAfter(a) == false
1673 * b.isAfter(a) == true
1674 * </pre>
1675 * <p>
1676 * This method only considers the position of the two dates on the local time-line.
1677 * It does not take into account the chronology, or calendar system.
1678 * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
1679 * but is the same approach as {@link #DATE_COMPARATOR}.
1680 *
1681 * @param other the other date to compare to, not null
1682 * @return true if this date is after the specified date
1683 */
1684 @Override // override for Javadoc and performance
1685 public boolean isAfter(ChronoLocalDate<?> other) {
1686 if (other instanceof LocalDate) {
1687 return compareTo0((LocalDate) other) > 0;
1688 }
1689 return ChronoLocalDate.super.isAfter(other);
1690 }
1691
1692 /**
1693 * Checks if this date is before the specified date.
1694 * <p>
1695 * This checks to see if this date represents a point on the
1696 * local time-line before the other date.
1697 * <pre>
1698 * LocalDate a = LocalDate.of(2012, 6, 30);
1699 * LocalDate b = LocalDate.of(2012, 7, 1);
1700 * a.isBefore(b) == true
1701 * a.isBefore(a) == false
1702 * b.isBefore(a) == false
1703 * </pre>
1704 * <p>
1705 * This method only considers the position of the two dates on the local time-line.
1706 * It does not take into account the chronology, or calendar system.
1707 * This is different from the comparison in {@link #compareTo(ChronoLocalDate)},
1708 * but is the same approach as {@link #DATE_COMPARATOR}.
1709 *
1710 * @param other the other date to compare to, not null
1711 * @return true if this date is before the specified date
1712 */
1713 @Override // override for Javadoc and performance
1714 public boolean isBefore(ChronoLocalDate<?> other) {
1715 if (other instanceof LocalDate) {
1716 return compareTo0((LocalDate) other) < 0;
1717 }
1718 return ChronoLocalDate.super.isBefore(other);
1719 }
1720
1721 /**
1722 * Checks if this date is equal to the specified date.
1723 * <p>
1724 * This checks to see if this date represents the same point on the
1725 * local time-line as the other date.
1726 * <pre>
1727 * LocalDate a = LocalDate.of(2012, 6, 30);
1728 * LocalDate b = LocalDate.of(2012, 7, 1);
1729 * a.isEqual(b) == false
1730 * a.isEqual(a) == true
1731 * b.isEqual(a) == false
1732 * </pre>
1733 * <p>
1734 * This method only considers the position of the two dates on the local time-line.
1735 * It does not take into account the chronology, or calendar system.
1736 * This is different from the comparison in {@link #compareTo(ChronoLocalDate)}
1737 * but is the same approach as {@link #DATE_COMPARATOR}.
1738 *
1739 * @param other the other date to compare to, not null
1740 * @return true if this date is equal to the specified date
1741 */
1742 @Override // override for Javadoc and performance
1743 public boolean isEqual(ChronoLocalDate<?> other) {
1744 if (other instanceof LocalDate) {
1745 return compareTo0((LocalDate) other) == 0;
1746 }
1747 return ChronoLocalDate.super.isEqual(other);
1748 }
1749
1750 //-----------------------------------------------------------------------
1751 /**
1752 * Checks if this date is equal to another date.
1753 * <p>
1754 * Compares this {@code LocalDate} with another ensuring that the date is the same.
1755 * <p>
1756 * Only objects of type {@code LocalDate} are compared, other types return false.
1757 * To compare the dates of two {@code TemporalAccessor} instances, including dates
1758 * in two different chronologies, use {@link ChronoField#EPOCH_DAY} as a comparator.
1759 *
1760 * @param obj the object to check, null returns false
1761 * @return true if this is equal to the other date
1762 */
1763 @Override
1764 public boolean equals(Object obj) {
1765 if (this == obj) {
1766 return true;
1767 }
1768 if (obj instanceof LocalDate) {
1769 return compareTo0((LocalDate) obj) == 0;
1770 }
1771 return false;
1772 }
1773
1774 /**
1775 * A hash code for this date.
1776 *
1777 * @return a suitable hash code
1778 */
1779 @Override
1780 public int hashCode() {
1781 int yearValue = year;
1782 int monthValue = month;
1783 int dayValue = day;
1784 return (yearValue & 0xFFFFF800) ^ ((yearValue << 11) + (monthValue << 6) + (dayValue));
1785 }
1786
1787 //-----------------------------------------------------------------------
1788 /**
1789 * Outputs this date as a {@code String}, such as {@code 2007-12-03}.
1790 * <p>
1791 * The output will be in the ISO-8601 format {@code yyyy-MM-dd}.
1792 *
1793 * @return a string representation of this date, not null
1794 */
1795 @Override
1796 public String toString() {
1797 int yearValue = year;
1798 int monthValue = month;
1799 int dayValue = day;
1800 int absYear = Math.abs(yearValue);
1801 StringBuilder buf = new StringBuilder(10);
1802 if (absYear < 1000) {
1803 if (yearValue < 0) {
1804 buf.append(yearValue - 10000).deleteCharAt(1);
1805 } else {
1806 buf.append(yearValue + 10000).deleteCharAt(0);
1807 }
1808 } else {
1809 if (yearValue > 9999) {
1810 buf.append('+');
1811 }
1812 buf.append(yearValue);
1813 }
1814 return buf.append(monthValue < 10 ? "-0" : "-")
1815 .append(monthValue)
1816 .append(dayValue < 10 ? "-0" : "-")
1817 .append(dayValue)
1818 .toString();
1819 }
1820
1821 /**
1822 * Outputs this date as a {@code String} using the formatter.
1823 * <p>
1824 * This date will be passed to the formatter
1825 * {@link DateTimeFormatter#print(TemporalAccessor) print method}.
1826 *
1827 * @param formatter the formatter to use, not null
1828 * @return the formatted date string, not null
1829 * @throws DateTimeException if an error occurs during printing
1830 */
1831 @Override // override for Javadoc
1832 public String toString(DateTimeFormatter formatter) {
1833 return ChronoLocalDate.super.toString(formatter);
1834 }
1835
1836 //-----------------------------------------------------------------------
1837 /**
1838 * Writes the object using a
1839 * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1840 * <pre>
1841 * out.writeByte(3); // identifies this as a LocalDate
1842 * out.writeInt(year);
1843 * out.writeByte(month);
1844 * out.writeByte(day);
1845 * </pre>
1846 *
1847 * @return the instance of {@code Ser}, not null
1848 */
1849 private Object writeReplace() {
1850 return new Ser(Ser.LOCAL_DATE_TYPE, this);
1851 }
1852
1853 /**
1854 * Defend against malicious streams.
1855 * @return never
1856 * @throws InvalidObjectException always
1857 */
1858 private Object readResolve() throws ObjectStreamException {
1859 throw new InvalidObjectException("Deserialization via serialization delegate");
1860 }
1861
1862 void writeExternal(DataOutput out) throws IOException {
1863 out.writeInt(year);
1864 out.writeByte(month);
1865 out.writeByte(day);
1866 }
1867
1868 static LocalDate readExternal(DataInput in) throws IOException {
1869 int year = in.readInt();
1870 int month = in.readByte();
1871 int dayOfMonth = in.readByte();
1872 return LocalDate.of(year, month, dayOfMonth);
1873 }
1874
1875 }