1 /*
2 * Copyright (c) 2012, 2023, 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
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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.temporal.ChronoField.DAY_OF_MONTH;
65 import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
66
67 import java.io.DataInput;
68 import java.io.DataOutput;
69 import java.io.IOException;
70 import java.io.InvalidObjectException;
71 import java.io.ObjectInputStream;
72 import java.io.Serializable;
73 import java.time.chrono.Chronology;
74 import java.time.chrono.IsoChronology;
75 import java.time.format.DateTimeFormatter;
76 import java.time.format.DateTimeFormatterBuilder;
77 import java.time.format.DateTimeParseException;
78 import java.time.temporal.ChronoField;
79 import java.time.temporal.Temporal;
80 import java.time.temporal.TemporalAccessor;
81 import java.time.temporal.TemporalAdjuster;
82 import java.time.temporal.TemporalField;
83 import java.time.temporal.TemporalQueries;
84 import java.time.temporal.TemporalQuery;
85 import java.time.temporal.UnsupportedTemporalTypeException;
86 import java.time.temporal.ValueRange;
87 import java.util.Objects;
88
89 /**
90 * A month-day in the ISO-8601 calendar system, such as {@code --12-03}.
91 * <p>
92 * {@code MonthDay} is an immutable date-time object that represents the combination
93 * of a month and day-of-month. Any field that can be derived from a month and day,
94 * such as quarter-of-year, can be obtained.
95 * <p>
96 * This class does not store or represent a year, time or time-zone.
97 * For example, the value "December 3rd" can be stored in a {@code MonthDay}.
98 * <p>
99 * Since a {@code MonthDay} does not possess a year, the leap day of
100 * February 29th is considered valid.
101 * <p>
102 * This class implements {@link TemporalAccessor} rather than {@link Temporal}.
103 * This is because it is not possible to define whether February 29th is valid or not
104 * without external information, preventing the implementation of plus/minus.
105 * Related to this, {@code MonthDay} only provides access to query and set the fields
106 * {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH}.
107 * <p>
108 * The ISO-8601 calendar system is the modern civil calendar system used today
109 * in most of the world. It is equivalent to the proleptic Gregorian calendar
110 * system, in which today's rules for leap years are applied for all time.
111 * For most applications written today, the ISO-8601 rules are entirely suitable.
112 * However, any application that makes use of historical dates, and requires them
113 * to be accurate will find the ISO-8601 approach unsuitable.
114 * <p>
115 * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
116 * class; programmers should treat instances that are {@linkplain #equals(Object) equal}
117 * as interchangeable and should not use instances for synchronization, mutexes, or
118 * with {@linkplain java.lang.ref.Reference object references}.
119 *
120 * <div class="preview-block">
121 * <div class="preview-comment">
122 * When preview features are enabled, {@code MonthDay} is a {@linkplain Class#isValue value class}.
123 * Use of value class instances for synchronization, mutexes, or with
124 * {@linkplain java.lang.ref.Reference object references} result in
125 * {@link IdentityException}.
126 * </div>
127 * </div>
128 *
129 * @implSpec
130 * This class is immutable and thread-safe.
131 *
132 * @since 1.8
133 */
134 @jdk.internal.ValueBased
135 @jdk.internal.MigratedValueClass
136 public final class MonthDay
137 implements TemporalAccessor, TemporalAdjuster, Comparable<MonthDay>, Serializable {
138
139 /**
140 * Serialization version.
141 */
142 @java.io.Serial
143 private static final long serialVersionUID = -939150713474957432L;
144 /**
145 * Parser.
146 */
147 private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder()
148 .appendLiteral("--")
149 .appendValue(MONTH_OF_YEAR, 2)
150 .appendLiteral('-')
151 .appendValue(DAY_OF_MONTH, 2)
152 .toFormatter();
153
154 /**
155 * The month-of-year, not null.
156 */
157 private final int month;
158 /**
159 * The day-of-month.
160 */
161 private final int day;
162
163 //-----------------------------------------------------------------------
164 /**
165 * Obtains the current month-day from the system clock in the default time-zone.
166 * <p>
167 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
168 * time-zone to obtain the current month-day.
169 * <p>
170 * Using this method will prevent the ability to use an alternate clock for testing
171 * because the clock is hard-coded.
172 *
173 * @return the current month-day using the system clock and default time-zone, not null
174 */
175 public static MonthDay now() {
176 return now(Clock.systemDefaultZone());
177 }
178
179 /**
180 * Obtains the current month-day from the system clock in the specified time-zone.
181 * <p>
182 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current month-day.
183 * Specifying the time-zone avoids dependence on the default time-zone.
184 * <p>
185 * Using this method will prevent the ability to use an alternate clock for testing
186 * because the clock is hard-coded.
187 *
188 * @param zone the zone ID to use, not null
189 * @return the current month-day using the system clock, not null
190 */
191 public static MonthDay now(ZoneId zone) {
192 return now(Clock.system(zone));
193 }
194
195 /**
196 * Obtains the current month-day from the specified clock.
197 * <p>
198 * This will query the specified clock to obtain the current month-day.
199 * Using this method allows the use of an alternate clock for testing.
200 * The alternate clock may be introduced using {@link Clock dependency injection}.
201 *
202 * @param clock the clock to use, not null
203 * @return the current month-day, not null
204 */
205 public static MonthDay now(Clock clock) {
206 final LocalDate now = LocalDate.now(clock); // called once
207 return MonthDay.of(now.getMonth(), now.getDayOfMonth());
208 }
209
210 //-----------------------------------------------------------------------
211 /**
212 * Obtains an instance of {@code MonthDay}.
213 * <p>
214 * The day-of-month must be valid for the month within a leap year.
215 * Hence, for February, day 29 is valid.
216 * <p>
217 * For example, passing in April and day 31 will throw an exception, as
218 * there can never be April 31st in any year. By contrast, passing in
219 * February 29th is permitted, as that month-day can sometimes be valid.
220 *
221 * @param month the month-of-year to represent, not null
222 * @param dayOfMonth the day-of-month to represent, from 1 to 31
223 * @return the month-day, not null
224 * @throws DateTimeException if the value of any field is out of range,
225 * or if the day-of-month is invalid for the month
226 */
227 public static MonthDay of(Month month, int dayOfMonth) {
228 Objects.requireNonNull(month, "month");
229 DAY_OF_MONTH.checkValidValue(dayOfMonth);
230 if (dayOfMonth > month.maxLength()) {
231 throw new DateTimeException("Illegal value for DayOfMonth field, value " + dayOfMonth +
232 " is not valid for month " + month.name());
233 }
234 return new MonthDay(month.getValue(), dayOfMonth);
235 }
236
237 /**
238 * Obtains an instance of {@code MonthDay}.
239 * <p>
240 * The day-of-month must be valid for the month within a leap year.
241 * Hence, for month 2 (February), day 29 is valid.
242 * <p>
243 * For example, passing in month 4 (April) and day 31 will throw an exception, as
244 * there can never be April 31st in any year. By contrast, passing in
245 * February 29th is permitted, as that month-day can sometimes be valid.
246 *
247 * @param month the month-of-year to represent, from 1 (January) to 12 (December)
248 * @param dayOfMonth the day-of-month to represent, from 1 to 31
249 * @return the month-day, not null
250 * @throws DateTimeException if the value of any field is out of range,
251 * or if the day-of-month is invalid for the month
252 */
253 public static MonthDay of(int month, int dayOfMonth) {
254 return of(Month.of(month), dayOfMonth);
255 }
256
257 //-----------------------------------------------------------------------
258 /**
259 * Obtains an instance of {@code MonthDay} from a temporal object.
260 * <p>
261 * This obtains a month-day based on the specified temporal.
262 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
263 * which this factory converts to an instance of {@code MonthDay}.
264 * <p>
265 * The conversion extracts the {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} and
266 * {@link ChronoField#DAY_OF_MONTH DAY_OF_MONTH} fields.
267 * The extraction is only permitted if the temporal object has an ISO
268 * chronology, or can be converted to a {@code LocalDate}.
269 * <p>
270 * This method matches the signature of the functional interface {@link TemporalQuery}
271 * allowing it to be used as a query via method reference, {@code MonthDay::from}.
272 *
273 * @param temporal the temporal object to convert, not null
274 * @return the month-day, not null
275 * @throws DateTimeException if unable to convert to a {@code MonthDay}
276 */
277 public static MonthDay from(TemporalAccessor temporal) {
278 if (temporal instanceof MonthDay) {
279 return (MonthDay) temporal;
280 }
281 try {
282 if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) {
283 temporal = LocalDate.from(temporal);
284 }
285 return of(temporal.get(MONTH_OF_YEAR), temporal.get(DAY_OF_MONTH));
286 } catch (DateTimeException ex) {
287 throw new DateTimeException("Unable to obtain MonthDay from TemporalAccessor: " +
288 temporal + " of type " + temporal.getClass().getName(), ex);
289 }
290 }
291
292 //-----------------------------------------------------------------------
293 /**
294 * Obtains an instance of {@code MonthDay} from a text string such as {@code --12-03}.
295 * <p>
296 * The string must represent a valid month-day.
297 * The format is {@code --MM-dd}.
298 *
299 * @param text the text to parse such as "--12-03", not null
300 * @return the parsed month-day, not null
301 * @throws DateTimeParseException if the text cannot be parsed
302 */
303 public static MonthDay parse(CharSequence text) {
304 return parse(text, PARSER);
305 }
306
307 /**
308 * Obtains an instance of {@code MonthDay} from a text string using a specific formatter.
309 * <p>
310 * The text is parsed using the formatter, returning a month-day.
311 *
312 * @param text the text to parse, not null
313 * @param formatter the formatter to use, not null
314 * @return the parsed month-day, not null
315 * @throws DateTimeParseException if the text cannot be parsed
316 */
317 public static MonthDay parse(CharSequence text, DateTimeFormatter formatter) {
318 Objects.requireNonNull(formatter, "formatter");
319 return formatter.parse(text, MonthDay::from);
320 }
321
322 //-----------------------------------------------------------------------
323 /**
324 * Constructor, previously validated.
325 *
326 * @param month the month-of-year to represent, validated from 1 to 12
327 * @param dayOfMonth the day-of-month to represent, validated from 1 to 29-31
328 */
329 private MonthDay(int month, int dayOfMonth) {
330 this.month = month;
331 this.day = dayOfMonth;
332 }
333
334 //-----------------------------------------------------------------------
335 /**
336 * Checks if the specified field is supported.
337 * <p>
338 * This checks if this month-day can be queried for the specified field.
339 * If false, then calling the {@link #range(TemporalField) range} and
340 * {@link #get(TemporalField) get} methods will throw an exception.
341 * <p>
342 * If the field is a {@link ChronoField} then the query is implemented here.
343 * The supported fields are:
344 * <ul>
345 * <li>{@code MONTH_OF_YEAR}
346 * <li>{@code YEAR}
347 * </ul>
348 * All other {@code ChronoField} instances will return false.
349 * <p>
350 * If the field is not a {@code ChronoField}, then the result of this method
351 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
352 * passing {@code this} as the argument.
353 * Whether the field is supported is determined by the field.
354 *
355 * @param field the field to check, null returns false
356 * @return true if the field is supported on this month-day, false if not
357 */
358 @Override
359 public boolean isSupported(TemporalField field) {
360 if (field instanceof ChronoField) {
361 return field == MONTH_OF_YEAR || field == DAY_OF_MONTH;
362 }
363 return field != null && field.isSupportedBy(this);
364 }
365
366 /**
367 * Gets the range of valid values for the specified field.
368 * <p>
369 * The range object expresses the minimum and maximum valid values for a field.
370 * This month-day is used to enhance the accuracy of the returned range.
371 * If it is not possible to return the range, because the field is not supported
372 * or for some other reason, an exception is thrown.
373 * <p>
374 * If the field is a {@link ChronoField} then the query is implemented here.
375 * The {@link #isSupported(TemporalField) supported fields} will return
376 * appropriate range instances.
377 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
378 * <p>
379 * If the field is not a {@code ChronoField}, then the result of this method
380 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
381 * passing {@code this} as the argument.
382 * Whether the range can be obtained is determined by the field.
383 *
384 * @param field the field to query the range for, not null
385 * @return the range of valid values for the field, not null
386 * @throws DateTimeException if the range for the field cannot be obtained
387 * @throws UnsupportedTemporalTypeException if the field is not supported
388 */
389 @Override
390 public ValueRange range(TemporalField field) {
391 if (field == MONTH_OF_YEAR) {
392 return field.range();
393 } else if (field == DAY_OF_MONTH) {
394 return ValueRange.of(1, getMonth().minLength(), getMonth().maxLength());
395 }
396 return TemporalAccessor.super.range(field);
397 }
398
399 /**
400 * Gets the value of the specified field from this month-day as an {@code int}.
401 * <p>
402 * This queries this month-day for the value of the specified field.
403 * The returned value will always be within the valid range of values for the field.
404 * If it is not possible to return the value, because the field is not supported
405 * or for some other reason, an exception is thrown.
406 * <p>
407 * If the field is a {@link ChronoField} then the query is implemented here.
408 * The {@link #isSupported(TemporalField) supported fields} will return valid
409 * values based on this month-day.
410 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
411 * <p>
412 * If the field is not a {@code ChronoField}, then the result of this method
413 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
414 * passing {@code this} as the argument. Whether the value can be obtained,
415 * and what the value represents, is determined by the field.
416 *
417 * @param field the field to get, not null
418 * @return the value for the field
419 * @throws DateTimeException if a value for the field cannot be obtained or
420 * the value is outside the range of valid values for the field
421 * @throws UnsupportedTemporalTypeException if the field is not supported or
422 * the range of values exceeds an {@code int}
423 * @throws ArithmeticException if numeric overflow occurs
424 */
425 @Override // override for Javadoc
426 public int get(TemporalField field) {
427 return range(field).checkValidIntValue(getLong(field), field);
428 }
429
430 /**
431 * Gets the value of the specified field from this month-day as a {@code long}.
432 * <p>
433 * This queries this month-day for the value of the specified field.
434 * If it is not possible to return the value, because the field is not supported
435 * or for some other reason, an exception is thrown.
436 * <p>
437 * If the field is a {@link ChronoField} then the query is implemented here.
438 * The {@link #isSupported(TemporalField) supported fields} will return valid
439 * values based on this month-day.
440 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
441 * <p>
442 * If the field is not a {@code ChronoField}, then the result of this method
443 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
444 * passing {@code this} as the argument. Whether the value can be obtained,
445 * and what the value represents, is determined by the field.
446 *
447 * @param field the field to get, not null
448 * @return the value for the field
449 * @throws DateTimeException if a value for the field cannot be obtained
450 * @throws UnsupportedTemporalTypeException if the field is not supported
451 * @throws ArithmeticException if numeric overflow occurs
452 */
453 @Override
454 public long getLong(TemporalField field) {
455 if (field instanceof ChronoField chronoField) {
456 return switch (chronoField) {
457 // alignedDOW and alignedWOM not supported because they cannot be set in with()
458 case DAY_OF_MONTH -> day;
459 case MONTH_OF_YEAR -> month;
460 default -> throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
461 };
462 }
463 return field.getFrom(this);
464 }
465
466 //-----------------------------------------------------------------------
467 /**
468 * Gets the month-of-year field from 1 to 12.
469 * <p>
470 * This method returns the month as an {@code int} from 1 to 12.
471 * Application code is frequently clearer if the enum {@link Month}
472 * is used by calling {@link #getMonth()}.
473 *
474 * @return the month-of-year, from 1 to 12
475 * @see #getMonth()
476 */
477 public int getMonthValue() {
478 return month;
479 }
480
481 /**
482 * Gets the month-of-year field using the {@code Month} enum.
483 * <p>
484 * This method returns the enum {@link Month} for the month.
485 * This avoids confusion as to what {@code int} values mean.
486 * If you need access to the primitive {@code int} value then the enum
487 * provides the {@link Month#getValue() int value}.
488 *
489 * @return the month-of-year, not null
490 * @see #getMonthValue()
491 */
492 public Month getMonth() {
493 return Month.of(month);
494 }
495
496 /**
497 * Gets the day-of-month field.
498 * <p>
499 * This method returns the primitive {@code int} value for the day-of-month.
500 *
501 * @return the day-of-month, from 1 to 31
502 */
503 public int getDayOfMonth() {
504 return day;
505 }
506
507 //-----------------------------------------------------------------------
508 /**
509 * Checks if the year is valid for this month-day.
510 * <p>
511 * This method checks whether this month and day and the input year form
512 * a valid date. This can only return false for February 29th.
513 *
514 * @param year the year to validate
515 * @return true if the year is valid for this month-day
516 * @see Year#isValidMonthDay(MonthDay)
517 */
518 public boolean isValidYear(int year) {
519 return (day == 29 && month == 2 && Year.isLeap(year) == false) == false;
520 }
521
522 //-----------------------------------------------------------------------
523 /**
524 * Returns a copy of this {@code MonthDay} with the month-of-year altered.
525 * <p>
526 * This returns a month-day with the specified month.
527 * If the day-of-month is invalid for the specified month, the day will
528 * be adjusted to the last valid day-of-month.
529 * <p>
530 * This instance is immutable and unaffected by this method call.
531 *
532 * @param month the month-of-year to set in the returned month-day, from 1 (January) to 12 (December)
533 * @return a {@code MonthDay} based on this month-day with the requested month, not null
534 * @throws DateTimeException if the month-of-year value is invalid
535 */
536 public MonthDay withMonth(int month) {
537 return with(Month.of(month));
538 }
539
540 /**
541 * Returns a copy of this {@code MonthDay} with the month-of-year altered.
542 * <p>
543 * This returns a month-day with the specified month.
544 * If the day-of-month is invalid for the specified month, the day will
545 * be adjusted to the last valid day-of-month.
546 * <p>
547 * This instance is immutable and unaffected by this method call.
548 *
549 * @param month the month-of-year to set in the returned month-day, not null
550 * @return a {@code MonthDay} based on this month-day with the requested month, not null
551 */
552 public MonthDay with(Month month) {
553 Objects.requireNonNull(month, "month");
554 if (month.getValue() == this.month) {
555 return this;
556 }
557 int day = Math.min(this.day, month.maxLength());
558 return new MonthDay(month.getValue(), day);
559 }
560
561 /**
562 * Returns a copy of this {@code MonthDay} with the day-of-month altered.
563 * <p>
564 * This returns a month-day with the specified day-of-month.
565 * If the day-of-month is invalid for the month, an exception is thrown.
566 * <p>
567 * This instance is immutable and unaffected by this method call.
568 *
569 * @param dayOfMonth the day-of-month to set in the return month-day, from 1 to 31
570 * @return a {@code MonthDay} based on this month-day with the requested day, not null
571 * @throws DateTimeException if the day-of-month value is invalid,
572 * or if the day-of-month is invalid for the month
573 */
574 public MonthDay withDayOfMonth(int dayOfMonth) {
575 if (dayOfMonth == this.day) {
576 return this;
577 }
578 return of(month, dayOfMonth);
579 }
580
581 //-----------------------------------------------------------------------
582 /**
583 * Queries this month-day using the specified query.
584 * <p>
585 * This queries this month-day using the specified query strategy object.
586 * The {@code TemporalQuery} object defines the logic to be used to
587 * obtain the result. Read the documentation of the query to understand
588 * what the result of this method will be.
589 * <p>
590 * The result of this method is obtained by invoking the
591 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
592 * specified query passing {@code this} as the argument.
593 *
594 * @param <R> the type of the result
595 * @param query the query to invoke, not null
596 * @return the query result, null may be returned (defined by the query)
597 * @throws DateTimeException if unable to query (defined by the query)
598 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
599 */
600 @SuppressWarnings("unchecked")
601 @Override
602 public <R> R query(TemporalQuery<R> query) {
603 if (query == TemporalQueries.chronology()) {
604 return (R) IsoChronology.INSTANCE;
605 }
606 return TemporalAccessor.super.query(query);
607 }
608
609 /**
610 * Adjusts the specified temporal object to have this month-day.
611 * <p>
612 * This returns a temporal object of the same observable type as the input
613 * with the month and day-of-month changed to be the same as this.
614 * <p>
615 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
616 * twice, passing {@link ChronoField#MONTH_OF_YEAR} and
617 * {@link ChronoField#DAY_OF_MONTH} as the fields.
618 * If the specified temporal object does not use the ISO calendar system then
619 * a {@code DateTimeException} is thrown.
620 * <p>
621 * In most cases, it is clearer to reverse the calling pattern by using
622 * {@link Temporal#with(TemporalAdjuster)}:
623 * <pre>
624 * // these two lines are equivalent, but the second approach is recommended
625 * temporal = thisMonthDay.adjustInto(temporal);
626 * temporal = temporal.with(thisMonthDay);
627 * </pre>
628 * <p>
629 * This instance is immutable and unaffected by this method call.
630 *
631 * @param temporal the target object to be adjusted, not null
632 * @return the adjusted object, not null
633 * @throws DateTimeException if unable to make the adjustment
634 * @throws ArithmeticException if numeric overflow occurs
635 */
636 @Override
637 public Temporal adjustInto(Temporal temporal) {
638 if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) {
639 throw new DateTimeException("Adjustment only supported on ISO date-time");
640 }
641 temporal = temporal.with(MONTH_OF_YEAR, month);
642 return temporal.with(DAY_OF_MONTH, Math.min(temporal.range(DAY_OF_MONTH).getMaximum(), day));
643 }
644
645 /**
646 * Formats this month-day using the specified formatter.
647 * <p>
648 * This month-day will be passed to the formatter to produce a string.
649 *
650 * @param formatter the formatter to use, not null
651 * @return the formatted month-day string, not null
652 * @throws DateTimeException if an error occurs during printing
653 */
654 public String format(DateTimeFormatter formatter) {
655 Objects.requireNonNull(formatter, "formatter");
656 return formatter.format(this);
657 }
658
659 //-----------------------------------------------------------------------
660 /**
661 * Combines this month-day with a year to create a {@code LocalDate}.
662 * <p>
663 * This returns a {@code LocalDate} formed from this month-day and the specified year.
664 * <p>
665 * A month-day of February 29th will be adjusted to February 28th in the resulting
666 * date if the year is not a leap year.
667 * <p>
668 * This instance is immutable and unaffected by this method call.
669 *
670 * @param year the year to use, from MIN_YEAR to MAX_YEAR
671 * @return the local date formed from this month-day and the specified year, not null
672 * @throws DateTimeException if the year is outside the valid range of years
673 */
674 public LocalDate atYear(int year) {
675 return LocalDate.of(year, month, isValidYear(year) ? day : 28);
676 }
677
678 //-----------------------------------------------------------------------
679 /**
680 * Compares this month-day to another month-day.
681 * <p>
682 * The comparison is based first on value of the month, then on the value of the day.
683 * It is "consistent with equals", as defined by {@link Comparable}.
684 *
685 * @param other the other month-day to compare to, not null
686 * @return the comparator value, that is less than zero if this is before {@code other},
687 * zero if they are equal, greater than zero if this is after {@code other}
688 * @see #isBefore
689 * @see #isAfter
690 */
691 @Override
692 public int compareTo(MonthDay other) {
693 int cmp = (month - other.month);
694 if (cmp == 0) {
695 cmp = (day - other.day);
696 }
697 return cmp;
698 }
699
700 /**
701 * Checks if this month-day is after the specified month-day.
702 *
703 * @param other the other month-day to compare to, not null
704 * @return true if this is after the specified month-day
705 */
706 public boolean isAfter(MonthDay other) {
707 return compareTo(other) > 0;
708 }
709
710 /**
711 * Checks if this month-day is before the specified month-day.
712 *
713 * @param other the other month-day to compare to, not null
714 * @return true if this point is before the specified month-day
715 */
716 public boolean isBefore(MonthDay other) {
717 return compareTo(other) < 0;
718 }
719
720 //-----------------------------------------------------------------------
721 /**
722 * Checks if this month-day is equal to another month-day.
723 * <p>
724 * The comparison is based on the time-line position of the month-day within a year.
725 *
726 * @param obj the object to check, null returns false
727 * @return true if this is equal to the other month-day
728 */
729 @Override
730 public boolean equals(Object obj) {
731 if (this == obj) {
732 return true;
733 }
734 return (obj instanceof MonthDay other)
735 && month == other.month
736 && day == other.day;
737 }
738
739 /**
740 * A hash code for this month-day.
741 *
742 * @return a suitable hash code
743 */
744 @Override
745 public int hashCode() {
746 return (month << 6) + day;
747 }
748
749 //-----------------------------------------------------------------------
750 /**
751 * Outputs this month-day as a {@code String}, such as {@code --12-03}.
752 * <p>
753 * The output will be in the format {@code --MM-dd}:
754 *
755 * @return a string representation of this month-day, not null
756 */
757 @Override
758 public String toString() {
759 return new StringBuilder(10).append("--")
760 .append(month < 10 ? "0" : "").append(month)
761 .append(day < 10 ? "-0" : "-").append(day)
762 .toString();
763 }
764
765 //-----------------------------------------------------------------------
766 /**
767 * Writes the object using a
768 * <a href="{@docRoot}/serialized-form.html#java.time.Ser">dedicated serialized form</a>.
769 * @serialData
770 * <pre>
771 * out.writeByte(13); // identifies a MonthDay
772 * out.writeByte(month);
773 * out.writeByte(day);
774 * </pre>
775 *
776 * @return the instance of {@code Ser}, not null
777 */
778 @java.io.Serial
779 private Object writeReplace() {
780 return new Ser(Ser.MONTH_DAY_TYPE, this);
781 }
782
783 /**
784 * Defend against malicious streams.
785 *
786 * @param s the stream to read
787 * @throws InvalidObjectException always
788 */
789 @java.io.Serial
790 private void readObject(ObjectInputStream s) throws InvalidObjectException {
791 throw new InvalidObjectException("Deserialization via serialization delegate");
792 }
793
794 void writeExternal(DataOutput out) throws IOException {
795 out.writeByte(month);
796 out.writeByte(day);
797 }
798
799 static MonthDay readExternal(DataInput in) throws IOException {
800 byte month = in.readByte();
801 byte day = in.readByte();
802 return MonthDay.of(month, day);
803 }
804
805 }