1 /*
2 * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
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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 *
115 * <p>
116 * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
117 * class; use of identity-sensitive operations (including reference equality
118 * ({@code ==}), identity hash code, or synchronization) on instances of
119 * {@code MonthDay} may have unpredictable results and should be avoided.
120 * The {@code equals} method should be used for comparisons.
121 *
122 * @implSpec
123 * This class is immutable and thread-safe.
124 *
125 * @since 1.8
126 */
127 public final class MonthDay
128 implements TemporalAccessor, TemporalAdjuster, Comparable<MonthDay>, Serializable {
129
130 /**
131 * Serialization version.
132 */
133 private static final long serialVersionUID = -939150713474957432L;
134 /**
135 * Parser.
136 */
137 private static final DateTimeFormatter PARSER = new DateTimeFormatterBuilder()
138 .appendLiteral("--")
139 .appendValue(MONTH_OF_YEAR, 2)
140 .appendLiteral('-')
141 .appendValue(DAY_OF_MONTH, 2)
142 .toFormatter();
143
144 /**
145 * The month-of-year, not null.
146 */
147 private final int month;
148 /**
149 * The day-of-month.
150 */
151 private final int day;
152
153 //-----------------------------------------------------------------------
154 /**
155 * Obtains the current month-day from the system clock in the default time-zone.
156 * <p>
157 * This will query the {@link Clock#systemDefaultZone() system clock} in the default
158 * time-zone to obtain the current month-day.
159 * <p>
160 * Using this method will prevent the ability to use an alternate clock for testing
161 * because the clock is hard-coded.
162 *
163 * @return the current month-day using the system clock and default time-zone, not null
164 */
165 public static MonthDay now() {
166 return now(Clock.systemDefaultZone());
167 }
168
169 /**
170 * Obtains the current month-day from the system clock in the specified time-zone.
171 * <p>
172 * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current month-day.
173 * Specifying the time-zone avoids dependence on the default time-zone.
174 * <p>
175 * Using this method will prevent the ability to use an alternate clock for testing
176 * because the clock is hard-coded.
177 *
178 * @param zone the zone ID to use, not null
179 * @return the current month-day using the system clock, not null
180 */
181 public static MonthDay now(ZoneId zone) {
182 return now(Clock.system(zone));
183 }
184
185 /**
186 * Obtains the current month-day from the specified clock.
187 * <p>
188 * This will query the specified clock to obtain the current month-day.
189 * Using this method allows the use of an alternate clock for testing.
190 * The alternate clock may be introduced using {@link Clock dependency injection}.
191 *
192 * @param clock the clock to use, not null
193 * @return the current month-day, not null
194 */
195 public static MonthDay now(Clock clock) {
196 final LocalDate now = LocalDate.now(clock); // called once
197 return MonthDay.of(now.getMonth(), now.getDayOfMonth());
198 }
199
200 //-----------------------------------------------------------------------
201 /**
202 * Obtains an instance of {@code MonthDay}.
203 * <p>
204 * The day-of-month must be valid for the month within a leap year.
205 * Hence, for February, day 29 is valid.
206 * <p>
207 * For example, passing in April and day 31 will throw an exception, as
208 * there can never be April 31st in any year. By contrast, passing in
209 * February 29th is permitted, as that month-day can sometimes be valid.
210 *
211 * @param month the month-of-year to represent, not null
212 * @param dayOfMonth the day-of-month to represent, from 1 to 31
213 * @return the month-day, not null
214 * @throws DateTimeException if the value of any field is out of range,
215 * or if the day-of-month is invalid for the month
216 */
217 public static MonthDay of(Month month, int dayOfMonth) {
218 Objects.requireNonNull(month, "month");
219 DAY_OF_MONTH.checkValidValue(dayOfMonth);
220 if (dayOfMonth > month.maxLength()) {
221 throw new DateTimeException("Illegal value for DayOfMonth field, value " + dayOfMonth +
222 " is not valid for month " + month.name());
223 }
224 return new MonthDay(month.getValue(), dayOfMonth);
225 }
226
227 /**
228 * Obtains an instance of {@code MonthDay}.
229 * <p>
230 * The day-of-month must be valid for the month within a leap year.
231 * Hence, for month 2 (February), day 29 is valid.
232 * <p>
233 * For example, passing in month 4 (April) and day 31 will throw an exception, as
234 * there can never be April 31st in any year. By contrast, passing in
235 * February 29th is permitted, as that month-day can sometimes be valid.
236 *
237 * @param month the month-of-year to represent, from 1 (January) to 12 (December)
238 * @param dayOfMonth the day-of-month to represent, from 1 to 31
239 * @return the month-day, not null
240 * @throws DateTimeException if the value of any field is out of range,
241 * or if the day-of-month is invalid for the month
242 */
243 public static MonthDay of(int month, int dayOfMonth) {
244 return of(Month.of(month), dayOfMonth);
245 }
246
247 //-----------------------------------------------------------------------
248 /**
249 * Obtains an instance of {@code MonthDay} from a temporal object.
250 * <p>
251 * This obtains a month-day based on the specified temporal.
252 * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
253 * which this factory converts to an instance of {@code MonthDay}.
254 * <p>
255 * The conversion extracts the {@link ChronoField#MONTH_OF_YEAR MONTH_OF_YEAR} and
256 * {@link ChronoField#DAY_OF_MONTH DAY_OF_MONTH} fields.
257 * The extraction is only permitted if the temporal object has an ISO
258 * chronology, or can be converted to a {@code LocalDate}.
259 * <p>
260 * This method matches the signature of the functional interface {@link TemporalQuery}
261 * allowing it to be used as a query via method reference, {@code MonthDay::from}.
262 *
263 * @param temporal the temporal object to convert, not null
264 * @return the month-day, not null
265 * @throws DateTimeException if unable to convert to a {@code MonthDay}
266 */
267 public static MonthDay from(TemporalAccessor temporal) {
268 if (temporal instanceof MonthDay) {
269 return (MonthDay) temporal;
270 }
271 try {
272 if (IsoChronology.INSTANCE.equals(Chronology.from(temporal)) == false) {
273 temporal = LocalDate.from(temporal);
274 }
275 return of(temporal.get(MONTH_OF_YEAR), temporal.get(DAY_OF_MONTH));
276 } catch (DateTimeException ex) {
277 throw new DateTimeException("Unable to obtain MonthDay from TemporalAccessor: " +
278 temporal + " of type " + temporal.getClass().getName(), ex);
279 }
280 }
281
282 //-----------------------------------------------------------------------
283 /**
284 * Obtains an instance of {@code MonthDay} from a text string such as {@code --12-03}.
285 * <p>
286 * The string must represent a valid month-day.
287 * The format is {@code --MM-dd}.
288 *
289 * @param text the text to parse such as "--12-03", not null
290 * @return the parsed month-day, not null
291 * @throws DateTimeParseException if the text cannot be parsed
292 */
293 public static MonthDay parse(CharSequence text) {
294 return parse(text, PARSER);
295 }
296
297 /**
298 * Obtains an instance of {@code MonthDay} from a text string using a specific formatter.
299 * <p>
300 * The text is parsed using the formatter, returning a month-day.
301 *
302 * @param text the text to parse, not null
303 * @param formatter the formatter to use, not null
304 * @return the parsed month-day, not null
305 * @throws DateTimeParseException if the text cannot be parsed
306 */
307 public static MonthDay parse(CharSequence text, DateTimeFormatter formatter) {
308 Objects.requireNonNull(formatter, "formatter");
309 return formatter.parse(text, MonthDay::from);
310 }
311
312 //-----------------------------------------------------------------------
313 /**
314 * Constructor, previously validated.
315 *
316 * @param month the month-of-year to represent, validated from 1 to 12
317 * @param dayOfMonth the day-of-month to represent, validated from 1 to 29-31
318 */
319 private MonthDay(int month, int dayOfMonth) {
320 this.month = month;
321 this.day = dayOfMonth;
322 }
323
324 //-----------------------------------------------------------------------
325 /**
326 * Checks if the specified field is supported.
327 * <p>
328 * This checks if this month-day can be queried for the specified field.
329 * If false, then calling the {@link #range(TemporalField) range} and
330 * {@link #get(TemporalField) get} methods will throw an exception.
331 * <p>
332 * If the field is a {@link ChronoField} then the query is implemented here.
333 * The supported fields are:
334 * <ul>
335 * <li>{@code MONTH_OF_YEAR}
336 * <li>{@code YEAR}
337 * </ul>
338 * All other {@code ChronoField} instances will return false.
339 * <p>
340 * If the field is not a {@code ChronoField}, then the result of this method
341 * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
342 * passing {@code this} as the argument.
343 * Whether the field is supported is determined by the field.
344 *
345 * @param field the field to check, null returns false
346 * @return true if the field is supported on this month-day, false if not
347 */
348 @Override
349 public boolean isSupported(TemporalField field) {
350 if (field instanceof ChronoField) {
351 return field == MONTH_OF_YEAR || field == DAY_OF_MONTH;
352 }
353 return field != null && field.isSupportedBy(this);
354 }
355
356 /**
357 * Gets the range of valid values for the specified field.
358 * <p>
359 * The range object expresses the minimum and maximum valid values for a field.
360 * This month-day is used to enhance the accuracy of the returned range.
361 * If it is not possible to return the range, because the field is not supported
362 * or for some other reason, an exception is thrown.
363 * <p>
364 * If the field is a {@link ChronoField} then the query is implemented here.
365 * The {@link #isSupported(TemporalField) supported fields} will return
366 * appropriate range instances.
367 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
368 * <p>
369 * If the field is not a {@code ChronoField}, then the result of this method
370 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
371 * passing {@code this} as the argument.
372 * Whether the range can be obtained is determined by the field.
373 *
374 * @param field the field to query the range for, not null
375 * @return the range of valid values for the field, not null
376 * @throws DateTimeException if the range for the field cannot be obtained
377 * @throws UnsupportedTemporalTypeException if the field is not supported
378 */
379 @Override
380 public ValueRange range(TemporalField field) {
381 if (field == MONTH_OF_YEAR) {
382 return field.range();
383 } else if (field == DAY_OF_MONTH) {
384 return ValueRange.of(1, getMonth().minLength(), getMonth().maxLength());
385 }
386 return TemporalAccessor.super.range(field);
387 }
388
389 /**
390 * Gets the value of the specified field from this month-day as an {@code int}.
391 * <p>
392 * This queries this month-day for the value of the specified field.
393 * The returned value will always be within the valid range of values for the field.
394 * If it is not possible to return the value, because the field is not supported
395 * or for some other reason, an exception is thrown.
396 * <p>
397 * If the field is a {@link ChronoField} then the query is implemented here.
398 * The {@link #isSupported(TemporalField) supported fields} will return valid
399 * values based on this month-day.
400 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
401 * <p>
402 * If the field is not a {@code ChronoField}, then the result of this method
403 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
404 * passing {@code this} as the argument. Whether the value can be obtained,
405 * and what the value represents, is determined by the field.
406 *
407 * @param field the field to get, not null
408 * @return the value for the field
409 * @throws DateTimeException if a value for the field cannot be obtained or
410 * the value is outside the range of valid values for the field
411 * @throws UnsupportedTemporalTypeException if the field is not supported or
412 * the range of values exceeds an {@code int}
413 * @throws ArithmeticException if numeric overflow occurs
414 */
415 @Override // override for Javadoc
416 public int get(TemporalField field) {
417 return range(field).checkValidIntValue(getLong(field), field);
418 }
419
420 /**
421 * Gets the value of the specified field from this month-day as a {@code long}.
422 * <p>
423 * This queries this month-day for the value of the specified field.
424 * If it is not possible to return the value, because the field is not supported
425 * or for some other reason, an exception is thrown.
426 * <p>
427 * If the field is a {@link ChronoField} then the query is implemented here.
428 * The {@link #isSupported(TemporalField) supported fields} will return valid
429 * values based on this month-day.
430 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
431 * <p>
432 * If the field is not a {@code ChronoField}, then the result of this method
433 * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
434 * passing {@code this} as the argument. Whether the value can be obtained,
435 * and what the value represents, is determined by the field.
436 *
437 * @param field the field to get, not null
438 * @return the value for the field
439 * @throws DateTimeException if a value for the field cannot be obtained
440 * @throws UnsupportedTemporalTypeException if the field is not supported
441 * @throws ArithmeticException if numeric overflow occurs
442 */
443 @Override
444 public long getLong(TemporalField field) {
445 if (field instanceof ChronoField) {
446 switch ((ChronoField) field) {
447 // alignedDOW and alignedWOM not supported because they cannot be set in with()
448 case DAY_OF_MONTH: return day;
449 case MONTH_OF_YEAR: return month;
450 }
451 throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
452 }
453 return field.getFrom(this);
454 }
455
456 //-----------------------------------------------------------------------
457 /**
458 * Gets the month-of-year field from 1 to 12.
459 * <p>
460 * This method returns the month as an {@code int} from 1 to 12.
461 * Application code is frequently clearer if the enum {@link Month}
462 * is used by calling {@link #getMonth()}.
463 *
464 * @return the month-of-year, from 1 to 12
465 * @see #getMonth()
466 */
467 public int getMonthValue() {
468 return month;
469 }
470
471 /**
472 * Gets the month-of-year field using the {@code Month} enum.
473 * <p>
474 * This method returns the enum {@link Month} for the month.
475 * This avoids confusion as to what {@code int} values mean.
476 * If you need access to the primitive {@code int} value then the enum
477 * provides the {@link Month#getValue() int value}.
478 *
479 * @return the month-of-year, not null
480 * @see #getMonthValue()
481 */
482 public Month getMonth() {
483 return Month.of(month);
484 }
485
486 /**
487 * Gets the day-of-month field.
488 * <p>
489 * This method returns the primitive {@code int} value for the day-of-month.
490 *
491 * @return the day-of-month, from 1 to 31
492 */
493 public int getDayOfMonth() {
494 return day;
495 }
496
497 //-----------------------------------------------------------------------
498 /**
499 * Checks if the year is valid for this month-day.
500 * <p>
501 * This method checks whether this month and day and the input year form
502 * a valid date. This can only return false for February 29th.
503 *
504 * @param year the year to validate
505 * @return true if the year is valid for this month-day
506 * @see Year#isValidMonthDay(MonthDay)
507 */
508 public boolean isValidYear(int year) {
509 return (day == 29 && month == 2 && Year.isLeap(year) == false) == false;
510 }
511
512 //-----------------------------------------------------------------------
513 /**
514 * Returns a copy of this {@code MonthDay} with the month-of-year altered.
515 * <p>
516 * This returns a month-day with the specified month.
517 * If the day-of-month is invalid for the specified month, the day will
518 * be adjusted to the last valid day-of-month.
519 * <p>
520 * This instance is immutable and unaffected by this method call.
521 *
522 * @param month the month-of-year to set in the returned month-day, from 1 (January) to 12 (December)
523 * @return a {@code MonthDay} based on this month-day with the requested month, not null
524 * @throws DateTimeException if the month-of-year value is invalid
525 */
526 public MonthDay withMonth(int month) {
527 return with(Month.of(month));
528 }
529
530 /**
531 * Returns a copy of this {@code MonthDay} with the month-of-year altered.
532 * <p>
533 * This returns a month-day with the specified month.
534 * If the day-of-month is invalid for the specified month, the day will
535 * be adjusted to the last valid day-of-month.
536 * <p>
537 * This instance is immutable and unaffected by this method call.
538 *
539 * @param month the month-of-year to set in the returned month-day, not null
540 * @return a {@code MonthDay} based on this month-day with the requested month, not null
541 */
542 public MonthDay with(Month month) {
543 Objects.requireNonNull(month, "month");
544 if (month.getValue() == this.month) {
545 return this;
546 }
547 int day = Math.min(this.day, month.maxLength());
548 return new MonthDay(month.getValue(), day);
549 }
550
551 /**
552 * Returns a copy of this {@code MonthDay} with the day-of-month altered.
553 * <p>
554 * This returns a month-day with the specified day-of-month.
555 * If the day-of-month is invalid for the month, an exception is thrown.
556 * <p>
557 * This instance is immutable and unaffected by this method call.
558 *
559 * @param dayOfMonth the day-of-month to set in the return month-day, from 1 to 31
560 * @return a {@code MonthDay} based on this month-day with the requested day, not null
561 * @throws DateTimeException if the day-of-month value is invalid,
562 * or if the day-of-month is invalid for the month
563 */
564 public MonthDay withDayOfMonth(int dayOfMonth) {
565 if (dayOfMonth == this.day) {
566 return this;
567 }
568 return of(month, dayOfMonth);
569 }
570
571 //-----------------------------------------------------------------------
572 /**
573 * Queries this month-day using the specified query.
574 * <p>
575 * This queries this month-day using the specified query strategy object.
576 * The {@code TemporalQuery} object defines the logic to be used to
577 * obtain the result. Read the documentation of the query to understand
578 * what the result of this method will be.
579 * <p>
580 * The result of this method is obtained by invoking the
581 * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
582 * specified query passing {@code this} as the argument.
583 *
584 * @param <R> the type of the result
585 * @param query the query to invoke, not null
586 * @return the query result, null may be returned (defined by the query)
587 * @throws DateTimeException if unable to query (defined by the query)
588 * @throws ArithmeticException if numeric overflow occurs (defined by the query)
589 */
590 @SuppressWarnings("unchecked")
591 @Override
592 public <R> R query(TemporalQuery<R> query) {
593 if (query == TemporalQueries.chronology()) {
594 return (R) IsoChronology.INSTANCE;
595 }
596 return TemporalAccessor.super.query(query);
597 }
598
599 /**
600 * Adjusts the specified temporal object to have this month-day.
601 * <p>
602 * This returns a temporal object of the same observable type as the input
603 * with the month and day-of-month changed to be the same as this.
604 * <p>
605 * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
606 * twice, passing {@link ChronoField#MONTH_OF_YEAR} and
607 * {@link ChronoField#DAY_OF_MONTH} as the fields.
608 * If the specified temporal object does not use the ISO calendar system then
609 * a {@code DateTimeException} is thrown.
610 * <p>
611 * In most cases, it is clearer to reverse the calling pattern by using
612 * {@link Temporal#with(TemporalAdjuster)}:
613 * <pre>
614 * // these two lines are equivalent, but the second approach is recommended
615 * temporal = thisMonthDay.adjustInto(temporal);
616 * temporal = temporal.with(thisMonthDay);
617 * </pre>
618 * <p>
619 * This instance is immutable and unaffected by this method call.
620 *
621 * @param temporal the target object to be adjusted, not null
622 * @return the adjusted object, not null
623 * @throws DateTimeException if unable to make the adjustment
624 * @throws ArithmeticException if numeric overflow occurs
625 */
626 @Override
627 public Temporal adjustInto(Temporal temporal) {
628 if (Chronology.from(temporal).equals(IsoChronology.INSTANCE) == false) {
629 throw new DateTimeException("Adjustment only supported on ISO date-time");
630 }
631 temporal = temporal.with(MONTH_OF_YEAR, month);
632 return temporal.with(DAY_OF_MONTH, Math.min(temporal.range(DAY_OF_MONTH).getMaximum(), day));
633 }
634
635 /**
636 * Formats this month-day using the specified formatter.
637 * <p>
638 * This month-day will be passed to the formatter to produce a string.
639 *
640 * @param formatter the formatter to use, not null
641 * @return the formatted month-day string, not null
642 * @throws DateTimeException if an error occurs during printing
643 */
644 public String format(DateTimeFormatter formatter) {
645 Objects.requireNonNull(formatter, "formatter");
646 return formatter.format(this);
647 }
648
649 //-----------------------------------------------------------------------
650 /**
651 * Combines this month-day with a year to create a {@code LocalDate}.
652 * <p>
653 * This returns a {@code LocalDate} formed from this month-day and the specified year.
654 * <p>
655 * A month-day of February 29th will be adjusted to February 28th in the resulting
656 * date if the year is not a leap year.
657 * <p>
658 * This instance is immutable and unaffected by this method call.
659 *
660 * @param year the year to use, from MIN_YEAR to MAX_YEAR
661 * @return the local date formed from this month-day and the specified year, not null
662 * @throws DateTimeException if the year is outside the valid range of years
663 */
664 public LocalDate atYear(int year) {
665 return LocalDate.of(year, month, isValidYear(year) ? day : 28);
666 }
667
668 //-----------------------------------------------------------------------
669 /**
670 * Compares this month-day to another month-day.
671 * <p>
672 * The comparison is based first on value of the month, then on the value of the day.
673 * It is "consistent with equals", as defined by {@link Comparable}.
674 *
675 * @param other the other month-day to compare to, not null
676 * @return the comparator value, negative if less, positive if greater
677 */
678 @Override
679 public int compareTo(MonthDay other) {
680 int cmp = (month - other.month);
681 if (cmp == 0) {
682 cmp = (day - other.day);
683 }
684 return cmp;
685 }
686
687 /**
688 * Checks if this month-day is after the specified month-day.
689 *
690 * @param other the other month-day to compare to, not null
691 * @return true if this is after the specified month-day
692 */
693 public boolean isAfter(MonthDay other) {
694 return compareTo(other) > 0;
695 }
696
697 /**
698 * Checks if this month-day is before the specified month-day.
699 *
700 * @param other the other month-day to compare to, not null
701 * @return true if this point is before the specified month-day
702 */
703 public boolean isBefore(MonthDay other) {
704 return compareTo(other) < 0;
705 }
706
707 //-----------------------------------------------------------------------
708 /**
709 * Checks if this month-day is equal to another month-day.
710 * <p>
711 * The comparison is based on the time-line position of the month-day within a year.
712 *
713 * @param obj the object to check, null returns false
714 * @return true if this is equal to the other month-day
715 */
716 @Override
717 public boolean equals(Object obj) {
718 if (this == obj) {
719 return true;
720 }
721 if (obj instanceof MonthDay) {
722 MonthDay other = (MonthDay) obj;
723 return month == other.month && day == other.day;
724 }
725 return false;
726 }
727
728 /**
729 * A hash code for this month-day.
730 *
731 * @return a suitable hash code
732 */
733 @Override
734 public int hashCode() {
735 return (month << 6) + day;
736 }
737
738 //-----------------------------------------------------------------------
739 /**
740 * Outputs this month-day as a {@code String}, such as {@code --12-03}.
741 * <p>
742 * The output will be in the format {@code --MM-dd}:
743 *
744 * @return a string representation of this month-day, not null
745 */
746 @Override
747 public String toString() {
748 return new StringBuilder(10).append("--")
749 .append(month < 10 ? "0" : "").append(month)
750 .append(day < 10 ? "-0" : "-").append(day)
751 .toString();
752 }
753
754 //-----------------------------------------------------------------------
755 /**
756 * Writes the object using a
757 * <a href="{@docRoot}/serialized-form.html#java.time.Ser">dedicated serialized form</a>.
758 * @serialData
759 * <pre>
760 * out.writeByte(13); // identifies a MonthDay
761 * out.writeByte(month);
762 * out.writeByte(day);
763 * </pre>
764 *
765 * @return the instance of {@code Ser}, not null
766 */
767 private Object writeReplace() {
768 return new Ser(Ser.MONTH_DAY_TYPE, this);
769 }
770
771 /**
772 * Defend against malicious streams.
773 *
774 * @param s the stream to read
775 * @throws InvalidObjectException always
776 */
777 private void readObject(ObjectInputStream s) throws InvalidObjectException {
778 throw new InvalidObjectException("Deserialization via serialization delegate");
779 }
780
781 void writeExternal(DataOutput out) throws IOException {
782 out.writeByte(month);
783 out.writeByte(day);
784 }
785
786 static MonthDay readExternal(DataInput in) throws IOException {
787 byte month = in.readByte();
788 byte day = in.readByte();
789 return MonthDay.of(month, day);
790 }
791
792 }