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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:
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47   *    may be used to endorse or promote products derived from this software
48   *    without specific prior written permission.
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62  package java.time;
63  
64  import static java.time.LocalTime.HOURS_PER_DAY;
65  import static java.time.LocalTime.MICROS_PER_DAY;
66  import static java.time.LocalTime.MILLIS_PER_DAY;
67  import static java.time.LocalTime.MINUTES_PER_DAY;
68  import static java.time.LocalTime.NANOS_PER_DAY;
69  import static java.time.LocalTime.NANOS_PER_HOUR;
70  import static java.time.LocalTime.NANOS_PER_MINUTE;
71  import static java.time.LocalTime.NANOS_PER_SECOND;
72  import static java.time.LocalTime.SECONDS_PER_DAY;
73  import static java.time.temporal.ChronoField.NANO_OF_SECOND;
74  
75  import java.io.DataInput;
76  import java.io.DataOutput;
77  import java.io.IOException;
78  import java.io.InvalidObjectException;
79  import java.io.ObjectInputStream;
80  import java.io.Serializable;
81  import java.time.chrono.ChronoLocalDateTime;
82  import java.time.format.DateTimeFormatter;
83  import java.time.format.DateTimeParseException;
84  import java.time.temporal.ChronoField;
85  import java.time.temporal.ChronoUnit;
86  import java.time.temporal.Temporal;
87  import java.time.temporal.TemporalAccessor;
88  import java.time.temporal.TemporalAdjuster;
89  import java.time.temporal.TemporalAmount;
90  import java.time.temporal.TemporalField;
91  import java.time.temporal.TemporalQueries;
92  import java.time.temporal.TemporalQuery;
93  import java.time.temporal.TemporalUnit;
94  import java.time.temporal.UnsupportedTemporalTypeException;
95  import java.time.temporal.ValueRange;
96  import java.time.zone.ZoneRules;
97  import java.util.Objects;
98  
99  /**
100  * A date-time without a time-zone in the ISO-8601 calendar system,
101  * such as {@code 2007-12-03T10:15:30}.
102  * <p>
103  * {@code LocalDateTime} is an immutable date-time object that represents a date-time,
104  * often viewed as year-month-day-hour-minute-second. Other date and time fields,
105  * such as day-of-year, day-of-week and week-of-year, can also be accessed.
106  * Time is represented to nanosecond precision.
107  * For example, the value "2nd October 2007 at 13:45.30.123456789" can be
108  * stored in a {@code LocalDateTime}.
109  * <p>
110  * This class does not store or represent a time-zone.
111  * Instead, it is a description of the date, as used for birthdays, combined with
112  * the local time as seen on a wall clock.
113  * It cannot represent an instant on the time-line without additional information
114  * such as an offset or time-zone.
115  * <p>
116  * The ISO-8601 calendar system is the modern civil calendar system used today
117  * in most of the world. It is equivalent to the proleptic Gregorian calendar
118  * system, in which today's rules for leap years are applied for all time.
119  * For most applications written today, the ISO-8601 rules are entirely suitable.
120  * However, any application that makes use of historical dates, and requires them
121  * to be accurate will find the ISO-8601 approach unsuitable.
122  *
123  * <p>
124  * This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a>
125  * class; use of identity-sensitive operations (including reference equality
126  * ({@code ==}), identity hash code, or synchronization) on instances of
127  * {@code LocalDateTime} may have unpredictable results and should be avoided.
128  * The {@code equals} method should be used for comparisons.
129  *
130  * @implSpec
131  * This class is immutable and thread-safe.
132  *
133  * @since 1.8
134  */
135 public final class LocalDateTime
136         implements Temporal, TemporalAdjuster, ChronoLocalDateTime<LocalDate>, Serializable {
137 
138     /**
139      * The minimum supported {@code LocalDateTime}, '-999999999-01-01T00:00:00'.
140      * This is the local date-time of midnight at the start of the minimum date.
141      * This combines {@link LocalDate#MIN} and {@link LocalTime#MIN}.
142      * This could be used by an application as a "far past" date-time.
143      */
144     public static final LocalDateTime MIN = LocalDateTime.of(LocalDate.MIN, LocalTime.MIN);
145     /**
146      * The maximum supported {@code LocalDateTime}, '+999999999-12-31T23:59:59.999999999'.
147      * This is the local date-time just before midnight at the end of the maximum date.
148      * This combines {@link LocalDate#MAX} and {@link LocalTime#MAX}.
149      * This could be used by an application as a "far future" date-time.
150      */
151     public static final LocalDateTime MAX = LocalDateTime.of(LocalDate.MAX, LocalTime.MAX);
152 
153     /**
154      * Serialization version.
155      */
156     private static final long serialVersionUID = 6207766400415563566L;
157 
158     /**
159      * The date part.
160      */
161     private final LocalDate date;
162     /**
163      * The time part.
164      */
165     private final LocalTime time;
166 
167     //-----------------------------------------------------------------------
168     /**
169      * Obtains the current date-time from the system clock in the default time-zone.
170      * <p>
171      * This will query the {@link Clock#systemDefaultZone() system clock} in the default
172      * time-zone to obtain the current date-time.
173      * <p>
174      * Using this method will prevent the ability to use an alternate clock for testing
175      * because the clock is hard-coded.
176      *
177      * @return the current date-time using the system clock and default time-zone, not null
178      */
179     public static LocalDateTime now() {
180         return now(Clock.systemDefaultZone());
181     }
182 
183     /**
184      * Obtains the current date-time from the system clock in the specified time-zone.
185      * <p>
186      * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date-time.
187      * Specifying the time-zone avoids dependence on the default time-zone.
188      * <p>
189      * Using this method will prevent the ability to use an alternate clock for testing
190      * because the clock is hard-coded.
191      *
192      * @param zone  the zone ID to use, not null
193      * @return the current date-time using the system clock, not null
194      */
195     public static LocalDateTime now(ZoneId zone) {
196         return now(Clock.system(zone));
197     }
198 
199     /**
200      * Obtains the current date-time from the specified clock.
201      * <p>
202      * This will query the specified clock to obtain the current date-time.
203      * Using this method allows the use of an alternate clock for testing.
204      * The alternate clock may be introduced using {@link Clock dependency injection}.
205      *
206      * @param clock  the clock to use, not null
207      * @return the current date-time, not null
208      */
209     public static LocalDateTime now(Clock clock) {
210         Objects.requireNonNull(clock, "clock");
211         final Instant now = clock.instant();  // called once
212         ZoneOffset offset = clock.getZone().getRules().getOffset(now);
213         return ofEpochSecond(now.getEpochSecond(), now.getNano(), offset);
214     }
215 
216     //-----------------------------------------------------------------------
217     /**
218      * Obtains an instance of {@code LocalDateTime} from year, month,
219      * day, hour and minute, setting the second and nanosecond to zero.
220      * <p>
221      * This returns a {@code LocalDateTime} with the specified year, month,
222      * day-of-month, hour and minute.
223      * The day must be valid for the year and month, otherwise an exception will be thrown.
224      * The second and nanosecond fields will be set to zero.
225      *
226      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
227      * @param month  the month-of-year to represent, not null
228      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
229      * @param hour  the hour-of-day to represent, from 0 to 23
230      * @param minute  the minute-of-hour to represent, from 0 to 59
231      * @return the local date-time, not null
232      * @throws DateTimeException if the value of any field is out of range,
233      *  or if the day-of-month is invalid for the month-year
234      */
235     public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute) {
236         LocalDate date = LocalDate.of(year, month, dayOfMonth);
237         LocalTime time = LocalTime.of(hour, minute);
238         return new LocalDateTime(date, time);
239     }
240 
241     /**
242      * Obtains an instance of {@code LocalDateTime} from year, month,
243      * day, hour, minute and second, setting the nanosecond to zero.
244      * <p>
245      * This returns a {@code LocalDateTime} with the specified year, month,
246      * day-of-month, hour, minute and second.
247      * The day must be valid for the year and month, otherwise an exception will be thrown.
248      * The nanosecond field will be set to zero.
249      *
250      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
251      * @param month  the month-of-year to represent, not null
252      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
253      * @param hour  the hour-of-day to represent, from 0 to 23
254      * @param minute  the minute-of-hour to represent, from 0 to 59
255      * @param second  the second-of-minute to represent, from 0 to 59
256      * @return the local date-time, not null
257      * @throws DateTimeException if the value of any field is out of range,
258      *  or if the day-of-month is invalid for the month-year
259      */
260     public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute, int second) {
261         LocalDate date = LocalDate.of(year, month, dayOfMonth);
262         LocalTime time = LocalTime.of(hour, minute, second);
263         return new LocalDateTime(date, time);
264     }
265 
266     /**
267      * Obtains an instance of {@code LocalDateTime} from year, month,
268      * day, hour, minute, second and nanosecond.
269      * <p>
270      * This returns a {@code LocalDateTime} with the specified year, month,
271      * day-of-month, hour, minute, second and nanosecond.
272      * The day must be valid for the year and month, otherwise an exception will be thrown.
273      *
274      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
275      * @param month  the month-of-year to represent, not null
276      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
277      * @param hour  the hour-of-day to represent, from 0 to 23
278      * @param minute  the minute-of-hour to represent, from 0 to 59
279      * @param second  the second-of-minute to represent, from 0 to 59
280      * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999
281      * @return the local date-time, not null
282      * @throws DateTimeException if the value of any field is out of range,
283      *  or if the day-of-month is invalid for the month-year
284      */
285     public static LocalDateTime of(int year, Month month, int dayOfMonth, int hour, int minute, int second, int nanoOfSecond) {
286         LocalDate date = LocalDate.of(year, month, dayOfMonth);
287         LocalTime time = LocalTime.of(hour, minute, second, nanoOfSecond);
288         return new LocalDateTime(date, time);
289     }
290 
291     //-----------------------------------------------------------------------
292     /**
293      * Obtains an instance of {@code LocalDateTime} from year, month,
294      * day, hour and minute, setting the second and nanosecond to zero.
295      * <p>
296      * This returns a {@code LocalDateTime} with the specified year, month,
297      * day-of-month, hour and minute.
298      * The day must be valid for the year and month, otherwise an exception will be thrown.
299      * The second and nanosecond fields will be set to zero.
300      *
301      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
302      * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
303      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
304      * @param hour  the hour-of-day to represent, from 0 to 23
305      * @param minute  the minute-of-hour to represent, from 0 to 59
306      * @return the local date-time, not null
307      * @throws DateTimeException if the value of any field is out of range,
308      *  or if the day-of-month is invalid for the month-year
309      */
310     public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute) {
311         LocalDate date = LocalDate.of(year, month, dayOfMonth);
312         LocalTime time = LocalTime.of(hour, minute);
313         return new LocalDateTime(date, time);
314     }
315 
316     /**
317      * Obtains an instance of {@code LocalDateTime} from year, month,
318      * day, hour, minute and second, setting the nanosecond to zero.
319      * <p>
320      * This returns a {@code LocalDateTime} with the specified year, month,
321      * day-of-month, hour, minute and second.
322      * The day must be valid for the year and month, otherwise an exception will be thrown.
323      * The nanosecond field will be set to zero.
324      *
325      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
326      * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
327      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
328      * @param hour  the hour-of-day to represent, from 0 to 23
329      * @param minute  the minute-of-hour to represent, from 0 to 59
330      * @param second  the second-of-minute to represent, from 0 to 59
331      * @return the local date-time, not null
332      * @throws DateTimeException if the value of any field is out of range,
333      *  or if the day-of-month is invalid for the month-year
334      */
335     public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute, int second) {
336         LocalDate date = LocalDate.of(year, month, dayOfMonth);
337         LocalTime time = LocalTime.of(hour, minute, second);
338         return new LocalDateTime(date, time);
339     }
340 
341     /**
342      * Obtains an instance of {@code LocalDateTime} from year, month,
343      * day, hour, minute, second and nanosecond.
344      * <p>
345      * This returns a {@code LocalDateTime} with the specified year, month,
346      * day-of-month, hour, minute, second and nanosecond.
347      * The day must be valid for the year and month, otherwise an exception will be thrown.
348      *
349      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
350      * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
351      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
352      * @param hour  the hour-of-day to represent, from 0 to 23
353      * @param minute  the minute-of-hour to represent, from 0 to 59
354      * @param second  the second-of-minute to represent, from 0 to 59
355      * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999
356      * @return the local date-time, not null
357      * @throws DateTimeException if the value of any field is out of range,
358      *  or if the day-of-month is invalid for the month-year
359      */
360     public static LocalDateTime of(int year, int month, int dayOfMonth, int hour, int minute, int second, int nanoOfSecond) {
361         LocalDate date = LocalDate.of(year, month, dayOfMonth);
362         LocalTime time = LocalTime.of(hour, minute, second, nanoOfSecond);
363         return new LocalDateTime(date, time);
364     }
365 
366     /**
367      * Obtains an instance of {@code LocalDateTime} from a date and time.
368      *
369      * @param date  the local date, not null
370      * @param time  the local time, not null
371      * @return the local date-time, not null
372      */
373     public static LocalDateTime of(LocalDate date, LocalTime time) {
374         Objects.requireNonNull(date, "date");
375         Objects.requireNonNull(time, "time");
376         return new LocalDateTime(date, time);
377     }
378 
379     //-------------------------------------------------------------------------
380     /**
381      * Obtains an instance of {@code LocalDateTime} from an {@code Instant} and zone ID.
382      * <p>
383      * This creates a local date-time based on the specified instant.
384      * First, the offset from UTC/Greenwich is obtained using the zone ID and instant,
385      * which is simple as there is only one valid offset for each instant.
386      * Then, the instant and offset are used to calculate the local date-time.
387      *
388      * @param instant  the instant to create the date-time from, not null
389      * @param zone  the time-zone, which may be an offset, not null
390      * @return the local date-time, not null
391      * @throws DateTimeException if the result exceeds the supported range
392      */
393     public static LocalDateTime ofInstant(Instant instant, ZoneId zone) {
394         Objects.requireNonNull(instant, "instant");
395         Objects.requireNonNull(zone, "zone");
396         ZoneRules rules = zone.getRules();
397         ZoneOffset offset = rules.getOffset(instant);
398         return ofEpochSecond(instant.getEpochSecond(), instant.getNano(), offset);
399     }
400 
401     /**
402      * Obtains an instance of {@code LocalDateTime} using seconds from the
403      * epoch of 1970-01-01T00:00:00Z.
404      * <p>
405      * This allows the {@link ChronoField#INSTANT_SECONDS epoch-second} field
406      * to be converted to a local date-time. This is primarily intended for
407      * low-level conversions rather than general application usage.
408      *
409      * @param epochSecond  the number of seconds from the epoch of 1970-01-01T00:00:00Z
410      * @param nanoOfSecond  the nanosecond within the second, from 0 to 999,999,999
411      * @param offset  the zone offset, not null
412      * @return the local date-time, not null
413      * @throws DateTimeException if the result exceeds the supported range,
414      *  or if the nano-of-second is invalid
415      */
416     public static LocalDateTime ofEpochSecond(long epochSecond, int nanoOfSecond, ZoneOffset offset) {
417         Objects.requireNonNull(offset, "offset");
418         NANO_OF_SECOND.checkValidValue(nanoOfSecond);
419         long localSecond = epochSecond + offset.getTotalSeconds();  // overflow caught later
420         long localEpochDay = Math.floorDiv(localSecond, SECONDS_PER_DAY);
421         int secsOfDay = (int)Math.floorMod(localSecond, SECONDS_PER_DAY);
422         LocalDate date = LocalDate.ofEpochDay(localEpochDay);
423         LocalTime time = LocalTime.ofNanoOfDay(secsOfDay * NANOS_PER_SECOND + nanoOfSecond);
424         return new LocalDateTime(date, time);
425     }
426 
427     //-----------------------------------------------------------------------
428     /**
429      * Obtains an instance of {@code LocalDateTime} from a temporal object.
430      * <p>
431      * This obtains an offset time based on the specified temporal.
432      * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
433      * which this factory converts to an instance of {@code LocalDateTime}.
434      * <p>
435      * The conversion extracts and combines the {@code LocalDate} and the
436      * {@code LocalTime} from the temporal object.
437      * Implementations are permitted to perform optimizations such as accessing
438      * those fields that are equivalent to the relevant objects.
439      * <p>
440      * This method matches the signature of the functional interface {@link TemporalQuery}
441      * allowing it to be used as a query via method reference, {@code LocalDateTime::from}.
442      *
443      * @param temporal  the temporal object to convert, not null
444      * @return the local date-time, not null
445      * @throws DateTimeException if unable to convert to a {@code LocalDateTime}
446      */
447     public static LocalDateTime from(TemporalAccessor temporal) {
448         if (temporal instanceof LocalDateTime) {
449             return (LocalDateTime) temporal;
450         } else if (temporal instanceof ZonedDateTime) {
451             return ((ZonedDateTime) temporal).toLocalDateTime();
452         } else if (temporal instanceof OffsetDateTime) {
453             return ((OffsetDateTime) temporal).toLocalDateTime();
454         }
455         try {
456             LocalDate date = LocalDate.from(temporal);
457             LocalTime time = LocalTime.from(temporal);
458             return new LocalDateTime(date, time);
459         } catch (DateTimeException ex) {
460             throw new DateTimeException("Unable to obtain LocalDateTime from TemporalAccessor: " +
461                     temporal + " of type " + temporal.getClass().getName(), ex);
462         }
463     }
464 
465     //-----------------------------------------------------------------------
466     /**
467      * Obtains an instance of {@code LocalDateTime} from a text string such as {@code 2007-12-03T10:15:30}.
468      * <p>
469      * The string must represent a valid date-time and is parsed using
470      * {@link java.time.format.DateTimeFormatter#ISO_LOCAL_DATE_TIME}.
471      *
472      * @param text  the text to parse such as "2007-12-03T10:15:30", not null
473      * @return the parsed local date-time, not null
474      * @throws DateTimeParseException if the text cannot be parsed
475      */
476     public static LocalDateTime parse(CharSequence text) {
477         return parse(text, DateTimeFormatter.ISO_LOCAL_DATE_TIME);
478     }
479 
480     /**
481      * Obtains an instance of {@code LocalDateTime} from a text string using a specific formatter.
482      * <p>
483      * The text is parsed using the formatter, returning a date-time.
484      *
485      * @param text  the text to parse, not null
486      * @param formatter  the formatter to use, not null
487      * @return the parsed local date-time, not null
488      * @throws DateTimeParseException if the text cannot be parsed
489      */
490     public static LocalDateTime parse(CharSequence text, DateTimeFormatter formatter) {
491         Objects.requireNonNull(formatter, "formatter");
492         return formatter.parse(text, LocalDateTime::from);
493     }
494 
495     //-----------------------------------------------------------------------
496     /**
497      * Constructor.
498      *
499      * @param date  the date part of the date-time, validated not null
500      * @param time  the time part of the date-time, validated not null
501      */
502     private LocalDateTime(LocalDate date, LocalTime time) {
503         this.date = date;
504         this.time = time;
505     }
506 
507     /**
508      * Returns a copy of this date-time with the new date and time, checking
509      * to see if a new object is in fact required.
510      *
511      * @param newDate  the date of the new date-time, not null
512      * @param newTime  the time of the new date-time, not null
513      * @return the date-time, not null
514      */
515     private LocalDateTime with(LocalDate newDate, LocalTime newTime) {
516         if (date == newDate && time == newTime) {
517             return this;
518         }
519         return new LocalDateTime(newDate, newTime);
520     }
521 
522     //-----------------------------------------------------------------------
523     /**
524      * Checks if the specified field is supported.
525      * <p>
526      * This checks if this date-time can be queried for the specified field.
527      * If false, then calling the {@link #range(TemporalField) range},
528      * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
529      * methods will throw an exception.
530      * <p>
531      * If the field is a {@link ChronoField} then the query is implemented here.
532      * The supported fields are:
533      * <ul>
534      * <li>{@code NANO_OF_SECOND}
535      * <li>{@code NANO_OF_DAY}
536      * <li>{@code MICRO_OF_SECOND}
537      * <li>{@code MICRO_OF_DAY}
538      * <li>{@code MILLI_OF_SECOND}
539      * <li>{@code MILLI_OF_DAY}
540      * <li>{@code SECOND_OF_MINUTE}
541      * <li>{@code SECOND_OF_DAY}
542      * <li>{@code MINUTE_OF_HOUR}
543      * <li>{@code MINUTE_OF_DAY}
544      * <li>{@code HOUR_OF_AMPM}
545      * <li>{@code CLOCK_HOUR_OF_AMPM}
546      * <li>{@code HOUR_OF_DAY}
547      * <li>{@code CLOCK_HOUR_OF_DAY}
548      * <li>{@code AMPM_OF_DAY}
549      * <li>{@code DAY_OF_WEEK}
550      * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
551      * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
552      * <li>{@code DAY_OF_MONTH}
553      * <li>{@code DAY_OF_YEAR}
554      * <li>{@code EPOCH_DAY}
555      * <li>{@code ALIGNED_WEEK_OF_MONTH}
556      * <li>{@code ALIGNED_WEEK_OF_YEAR}
557      * <li>{@code MONTH_OF_YEAR}
558      * <li>{@code PROLEPTIC_MONTH}
559      * <li>{@code YEAR_OF_ERA}
560      * <li>{@code YEAR}
561      * <li>{@code ERA}
562      * </ul>
563      * All other {@code ChronoField} instances will return false.
564      * <p>
565      * If the field is not a {@code ChronoField}, then the result of this method
566      * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
567      * passing {@code this} as the argument.
568      * Whether the field is supported is determined by the field.
569      *
570      * @param field  the field to check, null returns false
571      * @return true if the field is supported on this date-time, false if not
572      */
573     @Override
574     public boolean isSupported(TemporalField field) {
575         if (field instanceof ChronoField) {
576             ChronoField f = (ChronoField) field;
577             return f.isDateBased() || f.isTimeBased();
578         }
579         return field != null && field.isSupportedBy(this);
580     }
581 
582     /**
583      * Checks if the specified unit is supported.
584      * <p>
585      * This checks if the specified unit can be added to, or subtracted from, this date-time.
586      * If false, then calling the {@link #plus(long, TemporalUnit)} and
587      * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
588      * <p>
589      * If the unit is a {@link ChronoUnit} then the query is implemented here.
590      * The supported units are:
591      * <ul>
592      * <li>{@code NANOS}
593      * <li>{@code MICROS}
594      * <li>{@code MILLIS}
595      * <li>{@code SECONDS}
596      * <li>{@code MINUTES}
597      * <li>{@code HOURS}
598      * <li>{@code HALF_DAYS}
599      * <li>{@code DAYS}
600      * <li>{@code WEEKS}
601      * <li>{@code MONTHS}
602      * <li>{@code YEARS}
603      * <li>{@code DECADES}
604      * <li>{@code CENTURIES}
605      * <li>{@code MILLENNIA}
606      * <li>{@code ERAS}
607      * </ul>
608      * All other {@code ChronoUnit} instances will return false.
609      * <p>
610      * If the unit is not a {@code ChronoUnit}, then the result of this method
611      * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
612      * passing {@code this} as the argument.
613      * Whether the unit is supported is determined by the unit.
614      *
615      * @param unit  the unit to check, null returns false
616      * @return true if the unit can be added/subtracted, false if not
617      */
618     @Override  // override for Javadoc
619     public boolean isSupported(TemporalUnit unit) {
620         return ChronoLocalDateTime.super.isSupported(unit);
621     }
622 
623     //-----------------------------------------------------------------------
624     /**
625      * Gets the range of valid values for the specified field.
626      * <p>
627      * The range object expresses the minimum and maximum valid values for a field.
628      * This date-time is used to enhance the accuracy of the returned range.
629      * If it is not possible to return the range, because the field is not supported
630      * or for some other reason, an exception is thrown.
631      * <p>
632      * If the field is a {@link ChronoField} then the query is implemented here.
633      * The {@link #isSupported(TemporalField) supported fields} will return
634      * appropriate range instances.
635      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
636      * <p>
637      * If the field is not a {@code ChronoField}, then the result of this method
638      * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
639      * passing {@code this} as the argument.
640      * Whether the range can be obtained is determined by the field.
641      *
642      * @param field  the field to query the range for, not null
643      * @return the range of valid values for the field, not null
644      * @throws DateTimeException if the range for the field cannot be obtained
645      * @throws UnsupportedTemporalTypeException if the field is not supported
646      */
647     @Override
648     public ValueRange range(TemporalField field) {
649         if (field instanceof ChronoField) {
650             ChronoField f = (ChronoField) field;
651             return (f.isTimeBased() ? time.range(field) : date.range(field));
652         }
653         return field.rangeRefinedBy(this);
654     }
655 
656     /**
657      * Gets the value of the specified field from this date-time as an {@code int}.
658      * <p>
659      * This queries this date-time for the value for the specified field.
660      * The returned value will always be within the valid range of values for the field.
661      * If it is not possible to return the value, because the field is not supported
662      * or for some other reason, an exception is thrown.
663      * <p>
664      * If the field is a {@link ChronoField} then the query is implemented here.
665      * The {@link #isSupported(TemporalField) supported fields} will return valid
666      * values based on this date-time, except {@code NANO_OF_DAY}, {@code MICRO_OF_DAY},
667      * {@code EPOCH_DAY} and {@code PROLEPTIC_MONTH} which are too large to fit in
668      * an {@code int} and throw a {@code DateTimeException}.
669      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
670      * <p>
671      * If the field is not a {@code ChronoField}, then the result of this method
672      * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
673      * passing {@code this} as the argument. Whether the value can be obtained,
674      * and what the value represents, is determined by the field.
675      *
676      * @param field  the field to get, not null
677      * @return the value for the field
678      * @throws DateTimeException if a value for the field cannot be obtained or
679      *         the value is outside the range of valid values for the field
680      * @throws UnsupportedTemporalTypeException if the field is not supported or
681      *         the range of values exceeds an {@code int}
682      * @throws ArithmeticException if numeric overflow occurs
683      */
684     @Override
685     public int get(TemporalField field) {
686         if (field instanceof ChronoField) {
687             ChronoField f = (ChronoField) field;
688             return (f.isTimeBased() ? time.get(field) : date.get(field));
689         }
690         return ChronoLocalDateTime.super.get(field);
691     }
692 
693     /**
694      * Gets the value of the specified field from this date-time as a {@code long}.
695      * <p>
696      * This queries this date-time for the value for the specified field.
697      * If it is not possible to return the value, because the field is not supported
698      * or for some other reason, an exception is thrown.
699      * <p>
700      * If the field is a {@link ChronoField} then the query is implemented here.
701      * The {@link #isSupported(TemporalField) supported fields} will return valid
702      * values based on this date-time.
703      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
704      * <p>
705      * If the field is not a {@code ChronoField}, then the result of this method
706      * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
707      * passing {@code this} as the argument. Whether the value can be obtained,
708      * and what the value represents, is determined by the field.
709      *
710      * @param field  the field to get, not null
711      * @return the value for the field
712      * @throws DateTimeException if a value for the field cannot be obtained
713      * @throws UnsupportedTemporalTypeException if the field is not supported
714      * @throws ArithmeticException if numeric overflow occurs
715      */
716     @Override
717     public long getLong(TemporalField field) {
718         if (field instanceof ChronoField) {
719             ChronoField f = (ChronoField) field;
720             return (f.isTimeBased() ? time.getLong(field) : date.getLong(field));
721         }
722         return field.getFrom(this);
723     }
724 
725     //-----------------------------------------------------------------------
726     /**
727      * Gets the {@code LocalDate} part of this date-time.
728      * <p>
729      * This returns a {@code LocalDate} with the same year, month and day
730      * as this date-time.
731      *
732      * @return the date part of this date-time, not null
733      */
734     @Override
735     public LocalDate toLocalDate() {
736         return date;
737     }
738 
739     /**
740      * Gets the year field.
741      * <p>
742      * This method returns the primitive {@code int} value for the year.
743      * <p>
744      * The year returned by this method is proleptic as per {@code get(YEAR)}.
745      * To obtain the year-of-era, use {@code get(YEAR_OF_ERA)}.
746      *
747      * @return the year, from MIN_YEAR to MAX_YEAR
748      */
749     public int getYear() {
750         return date.getYear();
751     }
752 
753     /**
754      * Gets the month-of-year field from 1 to 12.
755      * <p>
756      * This method returns the month as an {@code int} from 1 to 12.
757      * Application code is frequently clearer if the enum {@link Month}
758      * is used by calling {@link #getMonth()}.
759      *
760      * @return the month-of-year, from 1 to 12
761      * @see #getMonth()
762      */
763     public int getMonthValue() {
764         return date.getMonthValue();
765     }
766 
767     /**
768      * Gets the month-of-year field using the {@code Month} enum.
769      * <p>
770      * This method returns the enum {@link Month} for the month.
771      * This avoids confusion as to what {@code int} values mean.
772      * If you need access to the primitive {@code int} value then the enum
773      * provides the {@link Month#getValue() int value}.
774      *
775      * @return the month-of-year, not null
776      * @see #getMonthValue()
777      */
778     public Month getMonth() {
779         return date.getMonth();
780     }
781 
782     /**
783      * Gets the day-of-month field.
784      * <p>
785      * This method returns the primitive {@code int} value for the day-of-month.
786      *
787      * @return the day-of-month, from 1 to 31
788      */
789     public int getDayOfMonth() {
790         return date.getDayOfMonth();
791     }
792 
793     /**
794      * Gets the day-of-year field.
795      * <p>
796      * This method returns the primitive {@code int} value for the day-of-year.
797      *
798      * @return the day-of-year, from 1 to 365, or 366 in a leap year
799      */
800     public int getDayOfYear() {
801         return date.getDayOfYear();
802     }
803 
804     /**
805      * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
806      * <p>
807      * This method returns the enum {@link DayOfWeek} for the day-of-week.
808      * This avoids confusion as to what {@code int} values mean.
809      * If you need access to the primitive {@code int} value then the enum
810      * provides the {@link DayOfWeek#getValue() int value}.
811      * <p>
812      * Additional information can be obtained from the {@code DayOfWeek}.
813      * This includes textual names of the values.
814      *
815      * @return the day-of-week, not null
816      */
817     public DayOfWeek getDayOfWeek() {
818         return date.getDayOfWeek();
819     }
820 
821     //-----------------------------------------------------------------------
822     /**
823      * Gets the {@code LocalTime} part of this date-time.
824      * <p>
825      * This returns a {@code LocalTime} with the same hour, minute, second and
826      * nanosecond as this date-time.
827      *
828      * @return the time part of this date-time, not null
829      */
830     @Override
831     public LocalTime toLocalTime() {
832         return time;
833     }
834 
835     /**
836      * Gets the hour-of-day field.
837      *
838      * @return the hour-of-day, from 0 to 23
839      */
840     public int getHour() {
841         return time.getHour();
842     }
843 
844     /**
845      * Gets the minute-of-hour field.
846      *
847      * @return the minute-of-hour, from 0 to 59
848      */
849     public int getMinute() {
850         return time.getMinute();
851     }
852 
853     /**
854      * Gets the second-of-minute field.
855      *
856      * @return the second-of-minute, from 0 to 59
857      */
858     public int getSecond() {
859         return time.getSecond();
860     }
861 
862     /**
863      * Gets the nano-of-second field.
864      *
865      * @return the nano-of-second, from 0 to 999,999,999
866      */
867     public int getNano() {
868         return time.getNano();
869     }
870 
871     //-----------------------------------------------------------------------
872     /**
873      * Returns an adjusted copy of this date-time.
874      * <p>
875      * This returns a {@code LocalDateTime}, based on this one, with the date-time adjusted.
876      * The adjustment takes place using the specified adjuster strategy object.
877      * Read the documentation of the adjuster to understand what adjustment will be made.
878      * <p>
879      * A simple adjuster might simply set the one of the fields, such as the year field.
880      * A more complex adjuster might set the date to the last day of the month.
881      * A selection of common adjustments is provided in {@link TemporalAdjuster}.
882      * These include finding the "last day of the month" and "next Wednesday".
883      * Key date-time classes also implement the {@code TemporalAdjuster} interface,
884      * such as {@link Month} and {@link java.time.MonthDay MonthDay}.
885      * The adjuster is responsible for handling special cases, such as the varying
886      * lengths of month and leap years.
887      * <p>
888      * For example this code returns a date on the last day of July:
889      * <pre>
890      *  import static java.time.Month.*;
891      *  import static java.time.temporal.Adjusters.*;
892      *
893      *  result = localDateTime.with(JULY).with(lastDayOfMonth());
894      * </pre>
895      * <p>
896      * The classes {@link LocalDate} and {@link LocalTime} implement {@code TemporalAdjuster},
897      * thus this method can be used to change the date, time or offset:
898      * <pre>
899      *  result = localDateTime.with(date);
900      *  result = localDateTime.with(time);
901      * </pre>
902      * <p>
903      * The result of this method is obtained by invoking the
904      * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
905      * specified adjuster passing {@code this} as the argument.
906      * <p>
907      * This instance is immutable and unaffected by this method call.
908      *
909      * @param adjuster the adjuster to use, not null
910      * @return a {@code LocalDateTime} based on {@code this} with the adjustment made, not null
911      * @throws DateTimeException if the adjustment cannot be made
912      * @throws ArithmeticException if numeric overflow occurs
913      */
914     @Override
915     public LocalDateTime with(TemporalAdjuster adjuster) {
916         // optimizations
917         if (adjuster instanceof LocalDate) {
918             return with((LocalDate) adjuster, time);
919         } else if (adjuster instanceof LocalTime) {
920             return with(date, (LocalTime) adjuster);
921         } else if (adjuster instanceof LocalDateTime) {
922             return (LocalDateTime) adjuster;
923         }
924         return (LocalDateTime) adjuster.adjustInto(this);
925     }
926 
927     /**
928      * Returns a copy of this date-time with the specified field set to a new value.
929      * <p>
930      * This returns a {@code LocalDateTime}, based on this one, with the value
931      * for the specified field changed.
932      * This can be used to change any supported field, such as the year, month or day-of-month.
933      * If it is not possible to set the value, because the field is not supported or for
934      * some other reason, an exception is thrown.
935      * <p>
936      * In some cases, changing the specified field can cause the resulting date-time to become invalid,
937      * such as changing the month from 31st January to February would make the day-of-month invalid.
938      * In cases like this, the field is responsible for resolving the date. Typically it will choose
939      * the previous valid date, which would be the last valid day of February in this example.
940      * <p>
941      * If the field is a {@link ChronoField} then the adjustment is implemented here.
942      * The {@link #isSupported(TemporalField) supported fields} will behave as per
943      * the matching method on {@link LocalDate#with(TemporalField, long) LocalDate}
944      * or {@link LocalTime#with(TemporalField, long) LocalTime}.
945      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
946      * <p>
947      * If the field is not a {@code ChronoField}, then the result of this method
948      * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
949      * passing {@code this} as the argument. In this case, the field determines
950      * whether and how to adjust the instant.
951      * <p>
952      * This instance is immutable and unaffected by this method call.
953      *
954      * @param field  the field to set in the result, not null
955      * @param newValue  the new value of the field in the result
956      * @return a {@code LocalDateTime} based on {@code this} with the specified field set, not null
957      * @throws DateTimeException if the field cannot be set
958      * @throws UnsupportedTemporalTypeException if the field is not supported
959      * @throws ArithmeticException if numeric overflow occurs
960      */
961     @Override
962     public LocalDateTime with(TemporalField field, long newValue) {
963         if (field instanceof ChronoField) {
964             ChronoField f = (ChronoField) field;
965             if (f.isTimeBased()) {
966                 return with(date, time.with(field, newValue));
967             } else {
968                 return with(date.with(field, newValue), time);
969             }
970         }
971         return field.adjustInto(this, newValue);
972     }
973 
974     //-----------------------------------------------------------------------
975     /**
976      * Returns a copy of this {@code LocalDateTime} with the year altered.
977      * The time does not affect the calculation and will be the same in the result.
978      * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
979      * <p>
980      * This instance is immutable and unaffected by this method call.
981      *
982      * @param year  the year to set in the result, from MIN_YEAR to MAX_YEAR
983      * @return a {@code LocalDateTime} based on this date-time with the requested year, not null
984      * @throws DateTimeException if the year value is invalid
985      */
986     public LocalDateTime withYear(int year) {
987         return with(date.withYear(year), time);
988     }
989 
990     /**
991      * Returns a copy of this {@code LocalDateTime} with the month-of-year altered.
992      * The time does not affect the calculation and will be the same in the result.
993      * If the day-of-month is invalid for the year, it will be changed to the last valid day of the month.
994      * <p>
995      * This instance is immutable and unaffected by this method call.
996      *
997      * @param month  the month-of-year to set in the result, from 1 (January) to 12 (December)
998      * @return a {@code LocalDateTime} based on this date-time with the requested month, not null
999      * @throws DateTimeException if the month-of-year value is invalid
1000      */
1001     public LocalDateTime withMonth(int month) {
1002         return with(date.withMonth(month), time);
1003     }
1004 
1005     /**
1006      * Returns a copy of this {@code LocalDateTime} with the day-of-month altered.
1007      * If the resulting {@code LocalDateTime} is invalid, an exception is thrown.
1008      * The time does not affect the calculation and will be the same in the result.
1009      * <p>
1010      * This instance is immutable and unaffected by this method call.
1011      *
1012      * @param dayOfMonth  the day-of-month to set in the result, from 1 to 28-31
1013      * @return a {@code LocalDateTime} based on this date-time with the requested day, not null
1014      * @throws DateTimeException if the day-of-month value is invalid,
1015      *  or if the day-of-month is invalid for the month-year
1016      */
1017     public LocalDateTime withDayOfMonth(int dayOfMonth) {
1018         return with(date.withDayOfMonth(dayOfMonth), time);
1019     }
1020 
1021     /**
1022      * Returns a copy of this {@code LocalDateTime} with the day-of-year altered.
1023      * If the resulting {@code LocalDateTime} is invalid, an exception is thrown.
1024      * <p>
1025      * This instance is immutable and unaffected by this method call.
1026      *
1027      * @param dayOfYear  the day-of-year to set in the result, from 1 to 365-366
1028      * @return a {@code LocalDateTime} based on this date with the requested day, not null
1029      * @throws DateTimeException if the day-of-year value is invalid,
1030      *  or if the day-of-year is invalid for the year
1031      */
1032     public LocalDateTime withDayOfYear(int dayOfYear) {
1033         return with(date.withDayOfYear(dayOfYear), time);
1034     }
1035 
1036     //-----------------------------------------------------------------------
1037     /**
1038      * Returns a copy of this {@code LocalDateTime} with the hour-of-day value altered.
1039      * <p>
1040      * This instance is immutable and unaffected by this method call.
1041      *
1042      * @param hour  the hour-of-day to set in the result, from 0 to 23
1043      * @return a {@code LocalDateTime} based on this date-time with the requested hour, not null
1044      * @throws DateTimeException if the hour value is invalid
1045      */
1046     public LocalDateTime withHour(int hour) {
1047         LocalTime newTime = time.withHour(hour);
1048         return with(date, newTime);
1049     }
1050 
1051     /**
1052      * Returns a copy of this {@code LocalDateTime} with the minute-of-hour value altered.
1053      * <p>
1054      * This instance is immutable and unaffected by this method call.
1055      *
1056      * @param minute  the minute-of-hour to set in the result, from 0 to 59
1057      * @return a {@code LocalDateTime} based on this date-time with the requested minute, not null
1058      * @throws DateTimeException if the minute value is invalid
1059      */
1060     public LocalDateTime withMinute(int minute) {
1061         LocalTime newTime = time.withMinute(minute);
1062         return with(date, newTime);
1063     }
1064 
1065     /**
1066      * Returns a copy of this {@code LocalDateTime} with the second-of-minute value altered.
1067      * <p>
1068      * This instance is immutable and unaffected by this method call.
1069      *
1070      * @param second  the second-of-minute to set in the result, from 0 to 59
1071      * @return a {@code LocalDateTime} based on this date-time with the requested second, not null
1072      * @throws DateTimeException if the second value is invalid
1073      */
1074     public LocalDateTime withSecond(int second) {
1075         LocalTime newTime = time.withSecond(second);
1076         return with(date, newTime);
1077     }
1078 
1079     /**
1080      * Returns a copy of this {@code LocalDateTime} with the nano-of-second value altered.
1081      * <p>
1082      * This instance is immutable and unaffected by this method call.
1083      *
1084      * @param nanoOfSecond  the nano-of-second to set in the result, from 0 to 999,999,999
1085      * @return a {@code LocalDateTime} based on this date-time with the requested nanosecond, not null
1086      * @throws DateTimeException if the nano value is invalid
1087      */
1088     public LocalDateTime withNano(int nanoOfSecond) {
1089         LocalTime newTime = time.withNano(nanoOfSecond);
1090         return with(date, newTime);
1091     }
1092 
1093     //-----------------------------------------------------------------------
1094     /**
1095      * Returns a copy of this {@code LocalDateTime} with the time truncated.
1096      * <p>
1097      * Truncation returns a copy of the original date-time with fields
1098      * smaller than the specified unit set to zero.
1099      * For example, truncating with the {@link ChronoUnit#MINUTES minutes} unit
1100      * will set the second-of-minute and nano-of-second field to zero.
1101      * <p>
1102      * The unit must have a {@linkplain TemporalUnit#getDuration() duration}
1103      * that divides into the length of a standard day without remainder.
1104      * This includes all supplied time units on {@link ChronoUnit} and
1105      * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception.
1106      * <p>
1107      * This instance is immutable and unaffected by this method call.
1108      *
1109      * @param unit  the unit to truncate to, not null
1110      * @return a {@code LocalDateTime} based on this date-time with the time truncated, not null
1111      * @throws DateTimeException if unable to truncate
1112      * @throws UnsupportedTemporalTypeException if the field is not supported
1113      */
1114     public LocalDateTime truncatedTo(TemporalUnit unit) {
1115         return with(date, time.truncatedTo(unit));
1116     }
1117 
1118     //-----------------------------------------------------------------------
1119     /**
1120      * Returns a copy of this date-time with the specified amount added.
1121      * <p>
1122      * This returns a {@code LocalDateTime}, based on this one, with the specified amount added.
1123      * The amount is typically {@link Period} or {@link Duration} but may be
1124      * any other type implementing the {@link TemporalAmount} interface.
1125      * <p>
1126      * The calculation is delegated to the amount object by calling
1127      * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
1128      * to implement the addition in any way it wishes, however it typically
1129      * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
1130      * of the amount implementation to determine if it can be successfully added.
1131      * <p>
1132      * This instance is immutable and unaffected by this method call.
1133      *
1134      * @param amountToAdd  the amount to add, not null
1135      * @return a {@code LocalDateTime} based on this date-time with the addition made, not null
1136      * @throws DateTimeException if the addition cannot be made
1137      * @throws ArithmeticException if numeric overflow occurs
1138      */
1139     @Override
1140     public LocalDateTime plus(TemporalAmount amountToAdd) {
1141         if (amountToAdd instanceof Period) {
1142             Period periodToAdd = (Period) amountToAdd;
1143             return with(date.plus(periodToAdd), time);
1144         }
1145         Objects.requireNonNull(amountToAdd, "amountToAdd");
1146         return (LocalDateTime) amountToAdd.addTo(this);
1147     }
1148 
1149     /**
1150      * Returns a copy of this date-time with the specified amount added.
1151      * <p>
1152      * This returns a {@code LocalDateTime}, based on this one, with the amount
1153      * in terms of the unit added. If it is not possible to add the amount, because the
1154      * unit is not supported or for some other reason, an exception is thrown.
1155      * <p>
1156      * If the field is a {@link ChronoUnit} then the addition is implemented here.
1157      * Date units are added as per {@link LocalDate#plus(long, TemporalUnit)}.
1158      * Time units are added as per {@link LocalTime#plus(long, TemporalUnit)} with
1159      * any overflow in days added equivalent to using {@link #plusDays(long)}.
1160      * <p>
1161      * If the field is not a {@code ChronoUnit}, then the result of this method
1162      * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
1163      * passing {@code this} as the argument. In this case, the unit determines
1164      * whether and how to perform the addition.
1165      * <p>
1166      * This instance is immutable and unaffected by this method call.
1167      *
1168      * @param amountToAdd  the amount of the unit to add to the result, may be negative
1169      * @param unit  the unit of the amount to add, not null
1170      * @return a {@code LocalDateTime} based on this date-time with the specified amount added, not null
1171      * @throws DateTimeException if the addition cannot be made
1172      * @throws UnsupportedTemporalTypeException if the unit is not supported
1173      * @throws ArithmeticException if numeric overflow occurs
1174      */
1175     @Override
1176     public LocalDateTime plus(long amountToAdd, TemporalUnit unit) {
1177         if (unit instanceof ChronoUnit) {
1178             ChronoUnit f = (ChronoUnit) unit;
1179             switch (f) {
1180                 case NANOS: return plusNanos(amountToAdd);
1181                 case MICROS: return plusDays(amountToAdd / MICROS_PER_DAY).plusNanos((amountToAdd % MICROS_PER_DAY) * 1000);
1182                 case MILLIS: return plusDays(amountToAdd / MILLIS_PER_DAY).plusNanos((amountToAdd % MILLIS_PER_DAY) * 1000_000);
1183                 case SECONDS: return plusSeconds(amountToAdd);
1184                 case MINUTES: return plusMinutes(amountToAdd);
1185                 case HOURS: return plusHours(amountToAdd);
1186                 case HALF_DAYS: return plusDays(amountToAdd / 256).plusHours((amountToAdd % 256) * 12);  // no overflow (256 is multiple of 2)
1187             }
1188             return with(date.plus(amountToAdd, unit), time);
1189         }
1190         return unit.addTo(this, amountToAdd);
1191     }
1192 
1193     //-----------------------------------------------------------------------
1194     /**
1195      * Returns a copy of this {@code LocalDateTime} with the specified period in years added.
1196      * <p>
1197      * This method adds the specified amount to the years field in three steps:
1198      * <ol>
1199      * <li>Add the input years to the year field</li>
1200      * <li>Check if the resulting date would be invalid</li>
1201      * <li>Adjust the day-of-month to the last valid day if necessary</li>
1202      * </ol>
1203      * <p>
1204      * For example, 2008-02-29 (leap year) plus one year would result in the
1205      * invalid date 2009-02-29 (standard year). Instead of returning an invalid
1206      * result, the last valid day of the month, 2009-02-28, is selected instead.
1207      * <p>
1208      * This instance is immutable and unaffected by this method call.
1209      *
1210      * @param years  the years to add, may be negative
1211      * @return a {@code LocalDateTime} based on this date-time with the years added, not null
1212      * @throws DateTimeException if the result exceeds the supported date range
1213      */
1214     public LocalDateTime plusYears(long years) {
1215         LocalDate newDate = date.plusYears(years);
1216         return with(newDate, time);
1217     }
1218 
1219     /**
1220      * Returns a copy of this {@code LocalDateTime} with the specified period in months added.
1221      * <p>
1222      * This method adds the specified amount to the months field in three steps:
1223      * <ol>
1224      * <li>Add the input months to the month-of-year field</li>
1225      * <li>Check if the resulting date would be invalid</li>
1226      * <li>Adjust the day-of-month to the last valid day if necessary</li>
1227      * </ol>
1228      * <p>
1229      * For example, 2007-03-31 plus one month would result in the invalid date
1230      * 2007-04-31. Instead of returning an invalid result, the last valid day
1231      * of the month, 2007-04-30, is selected instead.
1232      * <p>
1233      * This instance is immutable and unaffected by this method call.
1234      *
1235      * @param months  the months to add, may be negative
1236      * @return a {@code LocalDateTime} based on this date-time with the months added, not null
1237      * @throws DateTimeException if the result exceeds the supported date range
1238      */
1239     public LocalDateTime plusMonths(long months) {
1240         LocalDate newDate = date.plusMonths(months);
1241         return with(newDate, time);
1242     }
1243 
1244     /**
1245      * Returns a copy of this {@code LocalDateTime} with the specified period in weeks added.
1246      * <p>
1247      * This method adds the specified amount in weeks to the days field incrementing
1248      * the month and year fields as necessary to ensure the result remains valid.
1249      * The result is only invalid if the maximum/minimum year is exceeded.
1250      * <p>
1251      * For example, 2008-12-31 plus one week would result in 2009-01-07.
1252      * <p>
1253      * This instance is immutable and unaffected by this method call.
1254      *
1255      * @param weeks  the weeks to add, may be negative
1256      * @return a {@code LocalDateTime} based on this date-time with the weeks added, not null
1257      * @throws DateTimeException if the result exceeds the supported date range
1258      */
1259     public LocalDateTime plusWeeks(long weeks) {
1260         LocalDate newDate = date.plusWeeks(weeks);
1261         return with(newDate, time);
1262     }
1263 
1264     /**
1265      * Returns a copy of this {@code LocalDateTime} with the specified period in days added.
1266      * <p>
1267      * This method adds the specified amount to the days field incrementing the
1268      * month and year fields as necessary to ensure the result remains valid.
1269      * The result is only invalid if the maximum/minimum year is exceeded.
1270      * <p>
1271      * For example, 2008-12-31 plus one day would result in 2009-01-01.
1272      * <p>
1273      * This instance is immutable and unaffected by this method call.
1274      *
1275      * @param days  the days to add, may be negative
1276      * @return a {@code LocalDateTime} based on this date-time with the days added, not null
1277      * @throws DateTimeException if the result exceeds the supported date range
1278      */
1279     public LocalDateTime plusDays(long days) {
1280         LocalDate newDate = date.plusDays(days);
1281         return with(newDate, time);
1282     }
1283 
1284     //-----------------------------------------------------------------------
1285     /**
1286      * Returns a copy of this {@code LocalDateTime} with the specified period in hours added.
1287      * <p>
1288      * This instance is immutable and unaffected by this method call.
1289      *
1290      * @param hours  the hours to add, may be negative
1291      * @return a {@code LocalDateTime} based on this date-time with the hours added, not null
1292      * @throws DateTimeException if the result exceeds the supported date range
1293      */
1294     public LocalDateTime plusHours(long hours) {
1295         return plusWithOverflow(date, hours, 0, 0, 0, 1);
1296     }
1297 
1298     /**
1299      * Returns a copy of this {@code LocalDateTime} with the specified period in minutes added.
1300      * <p>
1301      * This instance is immutable and unaffected by this method call.
1302      *
1303      * @param minutes  the minutes to add, may be negative
1304      * @return a {@code LocalDateTime} based on this date-time with the minutes added, not null
1305      * @throws DateTimeException if the result exceeds the supported date range
1306      */
1307     public LocalDateTime plusMinutes(long minutes) {
1308         return plusWithOverflow(date, 0, minutes, 0, 0, 1);
1309     }
1310 
1311     /**
1312      * Returns a copy of this {@code LocalDateTime} with the specified period in seconds added.
1313      * <p>
1314      * This instance is immutable and unaffected by this method call.
1315      *
1316      * @param seconds  the seconds to add, may be negative
1317      * @return a {@code LocalDateTime} based on this date-time with the seconds added, not null
1318      * @throws DateTimeException if the result exceeds the supported date range
1319      */
1320     public LocalDateTime plusSeconds(long seconds) {
1321         return plusWithOverflow(date, 0, 0, seconds, 0, 1);
1322     }
1323 
1324     /**
1325      * Returns a copy of this {@code LocalDateTime} with the specified period in nanoseconds added.
1326      * <p>
1327      * This instance is immutable and unaffected by this method call.
1328      *
1329      * @param nanos  the nanos to add, may be negative
1330      * @return a {@code LocalDateTime} based on this date-time with the nanoseconds added, not null
1331      * @throws DateTimeException if the result exceeds the supported date range
1332      */
1333     public LocalDateTime plusNanos(long nanos) {
1334         return plusWithOverflow(date, 0, 0, 0, nanos, 1);
1335     }
1336 
1337     //-----------------------------------------------------------------------
1338     /**
1339      * Returns a copy of this date-time with the specified amount subtracted.
1340      * <p>
1341      * This returns a {@code LocalDateTime}, based on this one, with the specified amount subtracted.
1342      * The amount is typically {@link Period} or {@link Duration} but may be
1343      * any other type implementing the {@link TemporalAmount} interface.
1344      * <p>
1345      * The calculation is delegated to the amount object by calling
1346      * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
1347      * to implement the subtraction in any way it wishes, however it typically
1348      * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
1349      * of the amount implementation to determine if it can be successfully subtracted.
1350      * <p>
1351      * This instance is immutable and unaffected by this method call.
1352      *
1353      * @param amountToSubtract  the amount to subtract, not null
1354      * @return a {@code LocalDateTime} based on this date-time with the subtraction made, not null
1355      * @throws DateTimeException if the subtraction cannot be made
1356      * @throws ArithmeticException if numeric overflow occurs
1357      */
1358     @Override
1359     public LocalDateTime minus(TemporalAmount amountToSubtract) {
1360         if (amountToSubtract instanceof Period) {
1361             Period periodToSubtract = (Period) amountToSubtract;
1362             return with(date.minus(periodToSubtract), time);
1363         }
1364         Objects.requireNonNull(amountToSubtract, "amountToSubtract");
1365         return (LocalDateTime) amountToSubtract.subtractFrom(this);
1366     }
1367 
1368     /**
1369      * Returns a copy of this date-time with the specified amount subtracted.
1370      * <p>
1371      * This returns a {@code LocalDateTime}, based on this one, with the amount
1372      * in terms of the unit subtracted. If it is not possible to subtract the amount,
1373      * because the unit is not supported or for some other reason, an exception is thrown.
1374      * <p>
1375      * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
1376      * See that method for a full description of how addition, and thus subtraction, works.
1377      * <p>
1378      * This instance is immutable and unaffected by this method call.
1379      *
1380      * @param amountToSubtract  the amount of the unit to subtract from the result, may be negative
1381      * @param unit  the unit of the amount to subtract, not null
1382      * @return a {@code LocalDateTime} based on this date-time with the specified amount subtracted, not null
1383      * @throws DateTimeException if the subtraction cannot be made
1384      * @throws UnsupportedTemporalTypeException if the unit is not supported
1385      * @throws ArithmeticException if numeric overflow occurs
1386      */
1387     @Override
1388     public LocalDateTime minus(long amountToSubtract, TemporalUnit unit) {
1389         return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
1390     }
1391 
1392     //-----------------------------------------------------------------------
1393     /**
1394      * Returns a copy of this {@code LocalDateTime} with the specified period in years subtracted.
1395      * <p>
1396      * This method subtracts the specified amount from the years field in three steps:
1397      * <ol>
1398      * <li>Subtract the input years from the year field</li>
1399      * <li>Check if the resulting date would be invalid</li>
1400      * <li>Adjust the day-of-month to the last valid day if necessary</li>
1401      * </ol>
1402      * <p>
1403      * For example, 2008-02-29 (leap year) minus one year would result in the
1404      * invalid date 2009-02-29 (standard year). Instead of returning an invalid
1405      * result, the last valid day of the month, 2009-02-28, is selected instead.
1406      * <p>
1407      * This instance is immutable and unaffected by this method call.
1408      *
1409      * @param years  the years to subtract, may be negative
1410      * @return a {@code LocalDateTime} based on this date-time with the years subtracted, not null
1411      * @throws DateTimeException if the result exceeds the supported date range
1412      */
1413     public LocalDateTime minusYears(long years) {
1414         return (years == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-years));
1415     }
1416 
1417     /**
1418      * Returns a copy of this {@code LocalDateTime} with the specified period in months subtracted.
1419      * <p>
1420      * This method subtracts the specified amount from the months field in three steps:
1421      * <ol>
1422      * <li>Subtract the input months from the month-of-year field</li>
1423      * <li>Check if the resulting date would be invalid</li>
1424      * <li>Adjust the day-of-month to the last valid day if necessary</li>
1425      * </ol>
1426      * <p>
1427      * For example, 2007-03-31 minus one month would result in the invalid date
1428      * 2007-04-31. Instead of returning an invalid result, the last valid day
1429      * of the month, 2007-04-30, is selected instead.
1430      * <p>
1431      * This instance is immutable and unaffected by this method call.
1432      *
1433      * @param months  the months to subtract, may be negative
1434      * @return a {@code LocalDateTime} based on this date-time with the months subtracted, not null
1435      * @throws DateTimeException if the result exceeds the supported date range
1436      */
1437     public LocalDateTime minusMonths(long months) {
1438         return (months == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-months));
1439     }
1440 
1441     /**
1442      * Returns a copy of this {@code LocalDateTime} with the specified period in weeks subtracted.
1443      * <p>
1444      * This method subtracts the specified amount in weeks from the days field decrementing
1445      * the month and year fields as necessary to ensure the result remains valid.
1446      * The result is only invalid if the maximum/minimum year is exceeded.
1447      * <p>
1448      * For example, 2009-01-07 minus one week would result in 2008-12-31.
1449      * <p>
1450      * This instance is immutable and unaffected by this method call.
1451      *
1452      * @param weeks  the weeks to subtract, may be negative
1453      * @return a {@code LocalDateTime} based on this date-time with the weeks subtracted, not null
1454      * @throws DateTimeException if the result exceeds the supported date range
1455      */
1456     public LocalDateTime minusWeeks(long weeks) {
1457         return (weeks == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1) : plusWeeks(-weeks));
1458     }
1459 
1460     /**
1461      * Returns a copy of this {@code LocalDateTime} with the specified period in days subtracted.
1462      * <p>
1463      * This method subtracts the specified amount from the days field incrementing the
1464      * month and year fields as necessary to ensure the result remains valid.
1465      * The result is only invalid if the maximum/minimum year is exceeded.
1466      * <p>
1467      * For example, 2009-01-01 minus one day would result in 2008-12-31.
1468      * <p>
1469      * This instance is immutable and unaffected by this method call.
1470      *
1471      * @param days  the days to subtract, may be negative
1472      * @return a {@code LocalDateTime} based on this date-time with the days subtracted, not null
1473      * @throws DateTimeException if the result exceeds the supported date range
1474      */
1475     public LocalDateTime minusDays(long days) {
1476         return (days == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-days));
1477     }
1478 
1479     //-----------------------------------------------------------------------
1480     /**
1481      * Returns a copy of this {@code LocalDateTime} with the specified period in hours subtracted.
1482      * <p>
1483      * This instance is immutable and unaffected by this method call.
1484      *
1485      * @param hours  the hours to subtract, may be negative
1486      * @return a {@code LocalDateTime} based on this date-time with the hours subtracted, not null
1487      * @throws DateTimeException if the result exceeds the supported date range
1488      */
1489     public LocalDateTime minusHours(long hours) {
1490         return plusWithOverflow(date, hours, 0, 0, 0, -1);
1491    }
1492 
1493     /**
1494      * Returns a copy of this {@code LocalDateTime} with the specified period in minutes subtracted.
1495      * <p>
1496      * This instance is immutable and unaffected by this method call.
1497      *
1498      * @param minutes  the minutes to subtract, may be negative
1499      * @return a {@code LocalDateTime} based on this date-time with the minutes subtracted, not null
1500      * @throws DateTimeException if the result exceeds the supported date range
1501      */
1502     public LocalDateTime minusMinutes(long minutes) {
1503         return plusWithOverflow(date, 0, minutes, 0, 0, -1);
1504     }
1505 
1506     /**
1507      * Returns a copy of this {@code LocalDateTime} with the specified period in seconds subtracted.
1508      * <p>
1509      * This instance is immutable and unaffected by this method call.
1510      *
1511      * @param seconds  the seconds to subtract, may be negative
1512      * @return a {@code LocalDateTime} based on this date-time with the seconds subtracted, not null
1513      * @throws DateTimeException if the result exceeds the supported date range
1514      */
1515     public LocalDateTime minusSeconds(long seconds) {
1516         return plusWithOverflow(date, 0, 0, seconds, 0, -1);
1517     }
1518 
1519     /**
1520      * Returns a copy of this {@code LocalDateTime} with the specified period in nanoseconds subtracted.
1521      * <p>
1522      * This instance is immutable and unaffected by this method call.
1523      *
1524      * @param nanos  the nanos to subtract, may be negative
1525      * @return a {@code LocalDateTime} based on this date-time with the nanoseconds subtracted, not null
1526      * @throws DateTimeException if the result exceeds the supported date range
1527      */
1528     public LocalDateTime minusNanos(long nanos) {
1529         return plusWithOverflow(date, 0, 0, 0, nanos, -1);
1530     }
1531 
1532     //-----------------------------------------------------------------------
1533     /**
1534      * Returns a copy of this {@code LocalDateTime} with the specified period added.
1535      * <p>
1536      * This instance is immutable and unaffected by this method call.
1537      *
1538      * @param newDate  the new date to base the calculation on, not null
1539      * @param hours  the hours to add, may be negative
1540      * @param minutes the minutes to add, may be negative
1541      * @param seconds the seconds to add, may be negative
1542      * @param nanos the nanos to add, may be negative
1543      * @param sign  the sign to determine add or subtract
1544      * @return the combined result, not null
1545      */
1546     private LocalDateTime plusWithOverflow(LocalDate newDate, long hours, long minutes, long seconds, long nanos, int sign) {
1547         // 9223372036854775808 long, 2147483648 int
1548         if ((hours | minutes | seconds | nanos) == 0) {
1549             return with(newDate, time);
1550         }
1551         long totDays = nanos / NANOS_PER_DAY +             //   max/24*60*60*1B
1552                 seconds / SECONDS_PER_DAY +                //   max/24*60*60
1553                 minutes / MINUTES_PER_DAY +                //   max/24*60
1554                 hours / HOURS_PER_DAY;                     //   max/24
1555         totDays *= sign;                                   // total max*0.4237...
1556         long totNanos = nanos % NANOS_PER_DAY +                    //   max  86400000000000
1557                 (seconds % SECONDS_PER_DAY) * NANOS_PER_SECOND +   //   max  86400000000000
1558                 (minutes % MINUTES_PER_DAY) * NANOS_PER_MINUTE +   //   max  86400000000000
1559                 (hours % HOURS_PER_DAY) * NANOS_PER_HOUR;          //   max  86400000000000
1560         long curNoD = time.toNanoOfDay();                       //   max  86400000000000
1561         totNanos = totNanos * sign + curNoD;                    // total 432000000000000
1562         totDays += Math.floorDiv(totNanos, NANOS_PER_DAY);
1563         long newNoD = Math.floorMod(totNanos, NANOS_PER_DAY);
1564         LocalTime newTime = (newNoD == curNoD ? time : LocalTime.ofNanoOfDay(newNoD));
1565         return with(newDate.plusDays(totDays), newTime);
1566     }
1567 
1568     //-----------------------------------------------------------------------
1569     /**
1570      * Queries this date-time using the specified query.
1571      * <p>
1572      * This queries this date-time using the specified query strategy object.
1573      * The {@code TemporalQuery} object defines the logic to be used to
1574      * obtain the result. Read the documentation of the query to understand
1575      * what the result of this method will be.
1576      * <p>
1577      * The result of this method is obtained by invoking the
1578      * {@link java.time.temporal.TemporalQuery#queryFrom(TemporalAccessor)} method on the
1579      * specified query passing {@code this} as the argument.
1580      *
1581      * @param <R> the type of the result
1582      * @param query  the query to invoke, not null
1583      * @return the query result, null may be returned (defined by the query)
1584      * @throws DateTimeException if unable to query (defined by the query)
1585      * @throws ArithmeticException if numeric overflow occurs (defined by the query)
1586      */
1587     @SuppressWarnings("unchecked")
1588     @Override  // override for Javadoc
1589     public <R> R query(TemporalQuery<R> query) {
1590         if (query == TemporalQueries.localDate()) {
1591             return (R) date;
1592         }
1593         return ChronoLocalDateTime.super.query(query);
1594     }
1595 
1596     /**
1597      * Adjusts the specified temporal object to have the same date and time as this object.
1598      * <p>
1599      * This returns a temporal object of the same observable type as the input
1600      * with the date and time changed to be the same as this.
1601      * <p>
1602      * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
1603      * twice, passing {@link ChronoField#EPOCH_DAY} and
1604      * {@link ChronoField#NANO_OF_DAY} as the fields.
1605      * <p>
1606      * In most cases, it is clearer to reverse the calling pattern by using
1607      * {@link Temporal#with(TemporalAdjuster)}:
1608      * <pre>
1609      *   // these two lines are equivalent, but the second approach is recommended
1610      *   temporal = thisLocalDateTime.adjustInto(temporal);
1611      *   temporal = temporal.with(thisLocalDateTime);
1612      * </pre>
1613      * <p>
1614      * This instance is immutable and unaffected by this method call.
1615      *
1616      * @param temporal  the target object to be adjusted, not null
1617      * @return the adjusted object, not null
1618      * @throws DateTimeException if unable to make the adjustment
1619      * @throws ArithmeticException if numeric overflow occurs
1620      */
1621     @Override  // override for Javadoc
1622     public Temporal adjustInto(Temporal temporal) {
1623         return ChronoLocalDateTime.super.adjustInto(temporal);
1624     }
1625 
1626     /**
1627      * Calculates the amount of time until another date-time in terms of the specified unit.
1628      * <p>
1629      * This calculates the amount of time between two {@code LocalDateTime}
1630      * objects in terms of a single {@code TemporalUnit}.
1631      * The start and end points are {@code this} and the specified date-time.
1632      * The result will be negative if the end is before the start.
1633      * The {@code Temporal} passed to this method is converted to a
1634      * {@code LocalDateTime} using {@link #from(TemporalAccessor)}.
1635      * For example, the amount in days between two date-times can be calculated
1636      * using {@code startDateTime.until(endDateTime, DAYS)}.
1637      * <p>
1638      * The calculation returns a whole number, representing the number of
1639      * complete units between the two date-times.
1640      * For example, the amount in months between 2012-06-15T00:00 and 2012-08-14T23:59
1641      * will only be one month as it is one minute short of two months.
1642      * <p>
1643      * There are two equivalent ways of using this method.
1644      * The first is to invoke this method.
1645      * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
1646      * <pre>
1647      *   // these two lines are equivalent
1648      *   amount = start.until(end, MONTHS);
1649      *   amount = MONTHS.between(start, end);
1650      * </pre>
1651      * The choice should be made based on which makes the code more readable.
1652      * <p>
1653      * The calculation is implemented in this method for {@link ChronoUnit}.
1654      * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
1655      * {@code MINUTES}, {@code HOURS} and {@code HALF_DAYS}, {@code DAYS},
1656      * {@code WEEKS}, {@code MONTHS}, {@code YEARS}, {@code DECADES},
1657      * {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS} are supported.
1658      * Other {@code ChronoUnit} values will throw an exception.
1659      * <p>
1660      * If the unit is not a {@code ChronoUnit}, then the result of this method
1661      * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
1662      * passing {@code this} as the first argument and the converted input temporal
1663      * as the second argument.
1664      * <p>
1665      * This instance is immutable and unaffected by this method call.
1666      *
1667      * @param endExclusive  the end date, exclusive, which is converted to a {@code LocalDateTime}, not null
1668      * @param unit  the unit to measure the amount in, not null
1669      * @return the amount of time between this date-time and the end date-time
1670      * @throws DateTimeException if the amount cannot be calculated, or the end
1671      *  temporal cannot be converted to a {@code LocalDateTime}
1672      * @throws UnsupportedTemporalTypeException if the unit is not supported
1673      * @throws ArithmeticException if numeric overflow occurs
1674      */
1675     @Override
1676     public long until(Temporal endExclusive, TemporalUnit unit) {
1677         LocalDateTime end = LocalDateTime.from(endExclusive);
1678         if (unit instanceof ChronoUnit) {
1679             if (unit.isTimeBased()) {
1680                 long amount = date.daysUntil(end.date);
1681                 if (amount == 0) {
1682                     return time.until(end.time, unit);
1683                 }
1684                 long timePart = end.time.toNanoOfDay() - time.toNanoOfDay();
1685                 if (amount > 0) {
1686                     amount--;  // safe
1687                     timePart += NANOS_PER_DAY;  // safe
1688                 } else {
1689                     amount++;  // safe
1690                     timePart -= NANOS_PER_DAY;  // safe
1691                 }
1692                 switch ((ChronoUnit) unit) {
1693                     case NANOS:
1694                         amount = Math.multiplyExact(amount, NANOS_PER_DAY);
1695                         break;
1696                     case MICROS:
1697                         amount = Math.multiplyExact(amount, MICROS_PER_DAY);
1698                         timePart = timePart / 1000;
1699                         break;
1700                     case MILLIS:
1701                         amount = Math.multiplyExact(amount, MILLIS_PER_DAY);
1702                         timePart = timePart / 1_000_000;
1703                         break;
1704                     case SECONDS:
1705                         amount = Math.multiplyExact(amount, SECONDS_PER_DAY);
1706                         timePart = timePart / NANOS_PER_SECOND;
1707                         break;
1708                     case MINUTES:
1709                         amount = Math.multiplyExact(amount, MINUTES_PER_DAY);
1710                         timePart = timePart / NANOS_PER_MINUTE;
1711                         break;
1712                     case HOURS:
1713                         amount = Math.multiplyExact(amount, HOURS_PER_DAY);
1714                         timePart = timePart / NANOS_PER_HOUR;
1715                         break;
1716                     case HALF_DAYS:
1717                         amount = Math.multiplyExact(amount, 2);
1718                         timePart = timePart / (NANOS_PER_HOUR * 12);
1719                         break;
1720                 }
1721                 return Math.addExact(amount, timePart);
1722             }
1723             LocalDate endDate = end.date;
1724             if (endDate.isAfter(date) && end.time.isBefore(time)) {
1725                 endDate = endDate.minusDays(1);
1726             } else if (endDate.isBefore(date) && end.time.isAfter(time)) {
1727                 endDate = endDate.plusDays(1);
1728             }
1729             return date.until(endDate, unit);
1730         }
1731         return unit.between(this, end);
1732     }
1733 
1734     /**
1735      * Formats this date-time using the specified formatter.
1736      * <p>
1737      * This date-time will be passed to the formatter to produce a string.
1738      *
1739      * @param formatter  the formatter to use, not null
1740      * @return the formatted date-time string, not null
1741      * @throws DateTimeException if an error occurs during printing
1742      */
1743     @Override  // override for Javadoc and performance
1744     public String format(DateTimeFormatter formatter) {
1745         Objects.requireNonNull(formatter, "formatter");
1746         return formatter.format(this);
1747     }
1748 
1749     //-----------------------------------------------------------------------
1750     /**
1751      * Combines this date-time with an offset to create an {@code OffsetDateTime}.
1752      * <p>
1753      * This returns an {@code OffsetDateTime} formed from this date-time at the specified offset.
1754      * All possible combinations of date-time and offset are valid.
1755      *
1756      * @param offset  the offset to combine with, not null
1757      * @return the offset date-time formed from this date-time and the specified offset, not null
1758      */
1759     public OffsetDateTime atOffset(ZoneOffset offset) {
1760         return OffsetDateTime.of(this, offset);
1761     }
1762 
1763     /**
1764      * Combines this date-time with a time-zone to create a {@code ZonedDateTime}.
1765      * <p>
1766      * This returns a {@code ZonedDateTime} formed from this date-time at the
1767      * specified time-zone. The result will match this date-time as closely as possible.
1768      * Time-zone rules, such as daylight savings, mean that not every local date-time
1769      * is valid for the specified zone, thus the local date-time may be adjusted.
1770      * <p>
1771      * The local date-time is resolved to a single instant on the time-line.
1772      * This is achieved by finding a valid offset from UTC/Greenwich for the local
1773      * date-time as defined by the {@link ZoneRules rules} of the zone ID.
1774      *<p>
1775      * In most cases, there is only one valid offset for a local date-time.
1776      * In the case of an overlap, where clocks are set back, there are two valid offsets.
1777      * This method uses the earlier offset typically corresponding to "summer".
1778      * <p>
1779      * In the case of a gap, where clocks jump forward, there is no valid offset.
1780      * Instead, the local date-time is adjusted to be later by the length of the gap.
1781      * For a typical one hour daylight savings change, the local date-time will be
1782      * moved one hour later into the offset typically corresponding to "summer".
1783      * <p>
1784      * To obtain the later offset during an overlap, call
1785      * {@link ZonedDateTime#withLaterOffsetAtOverlap()} on the result of this method.
1786      * To throw an exception when there is a gap or overlap, use
1787      * {@link ZonedDateTime#ofStrict(LocalDateTime, ZoneOffset, ZoneId)}.
1788      *
1789      * @param zone  the time-zone to use, not null
1790      * @return the zoned date-time formed from this date-time, not null
1791      */
1792     @Override
1793     public ZonedDateTime atZone(ZoneId zone) {
1794         return ZonedDateTime.of(this, zone);
1795     }
1796 
1797     //-----------------------------------------------------------------------
1798     /**
1799      * Compares this date-time to another date-time.
1800      * <p>
1801      * The comparison is primarily based on the date-time, from earliest to latest.
1802      * It is "consistent with equals", as defined by {@link Comparable}.
1803      * <p>
1804      * If all the date-times being compared are instances of {@code LocalDateTime},
1805      * then the comparison will be entirely based on the date-time.
1806      * If some dates being compared are in different chronologies, then the
1807      * chronology is also considered, see {@link ChronoLocalDateTime#compareTo}.
1808      *
1809      * @param other  the other date-time to compare to, not null
1810      * @return the comparator value, negative if less, positive if greater
1811      */
1812     @Override  // override for Javadoc and performance
1813     public int compareTo(ChronoLocalDateTime<?> other) {
1814         if (other instanceof LocalDateTime) {
1815             return compareTo0((LocalDateTime) other);
1816         }
1817         return ChronoLocalDateTime.super.compareTo(other);
1818     }
1819 
1820     private int compareTo0(LocalDateTime other) {
1821         int cmp = date.compareTo0(other.toLocalDate());
1822         if (cmp == 0) {
1823             cmp = time.compareTo(other.toLocalTime());
1824         }
1825         return cmp;
1826     }
1827 
1828     /**
1829      * Checks if this date-time is after the specified date-time.
1830      * <p>
1831      * This checks to see if this date-time represents a point on the
1832      * local time-line after the other date-time.
1833      * <pre>
1834      *   LocalDate a = LocalDateTime.of(2012, 6, 30, 12, 00);
1835      *   LocalDate b = LocalDateTime.of(2012, 7, 1, 12, 00);
1836      *   a.isAfter(b) == false
1837      *   a.isAfter(a) == false
1838      *   b.isAfter(a) == true
1839      * </pre>
1840      * <p>
1841      * This method only considers the position of the two date-times on the local time-line.
1842      * It does not take into account the chronology, or calendar system.
1843      * This is different from the comparison in {@link #compareTo(ChronoLocalDateTime)},
1844      * but is the same approach as {@link ChronoLocalDateTime#timeLineOrder()}.
1845      *
1846      * @param other  the other date-time to compare to, not null
1847      * @return true if this date-time is after the specified date-time
1848      */
1849     @Override  // override for Javadoc and performance
1850     public boolean isAfter(ChronoLocalDateTime<?> other) {
1851         if (other instanceof LocalDateTime) {
1852             return compareTo0((LocalDateTime) other) > 0;
1853         }
1854         return ChronoLocalDateTime.super.isAfter(other);
1855     }
1856 
1857     /**
1858      * Checks if this date-time is before the specified date-time.
1859      * <p>
1860      * This checks to see if this date-time represents a point on the
1861      * local time-line before the other date-time.
1862      * <pre>
1863      *   LocalDate a = LocalDateTime.of(2012, 6, 30, 12, 00);
1864      *   LocalDate b = LocalDateTime.of(2012, 7, 1, 12, 00);
1865      *   a.isBefore(b) == true
1866      *   a.isBefore(a) == false
1867      *   b.isBefore(a) == false
1868      * </pre>
1869      * <p>
1870      * This method only considers the position of the two date-times on the local time-line.
1871      * It does not take into account the chronology, or calendar system.
1872      * This is different from the comparison in {@link #compareTo(ChronoLocalDateTime)},
1873      * but is the same approach as {@link ChronoLocalDateTime#timeLineOrder()}.
1874      *
1875      * @param other  the other date-time to compare to, not null
1876      * @return true if this date-time is before the specified date-time
1877      */
1878     @Override  // override for Javadoc and performance
1879     public boolean isBefore(ChronoLocalDateTime<?> other) {
1880         if (other instanceof LocalDateTime) {
1881             return compareTo0((LocalDateTime) other) < 0;
1882         }
1883         return ChronoLocalDateTime.super.isBefore(other);
1884     }
1885 
1886     /**
1887      * Checks if this date-time is equal to the specified date-time.
1888      * <p>
1889      * This checks to see if this date-time represents the same point on the
1890      * local time-line as the other date-time.
1891      * <pre>
1892      *   LocalDate a = LocalDateTime.of(2012, 6, 30, 12, 00);
1893      *   LocalDate b = LocalDateTime.of(2012, 7, 1, 12, 00);
1894      *   a.isEqual(b) == false
1895      *   a.isEqual(a) == true
1896      *   b.isEqual(a) == false
1897      * </pre>
1898      * <p>
1899      * This method only considers the position of the two date-times on the local time-line.
1900      * It does not take into account the chronology, or calendar system.
1901      * This is different from the comparison in {@link #compareTo(ChronoLocalDateTime)},
1902      * but is the same approach as {@link ChronoLocalDateTime#timeLineOrder()}.
1903      *
1904      * @param other  the other date-time to compare to, not null
1905      * @return true if this date-time is equal to the specified date-time
1906      */
1907     @Override  // override for Javadoc and performance
1908     public boolean isEqual(ChronoLocalDateTime<?> other) {
1909         if (other instanceof LocalDateTime) {
1910             return compareTo0((LocalDateTime) other) == 0;
1911         }
1912         return ChronoLocalDateTime.super.isEqual(other);
1913     }
1914 
1915     //-----------------------------------------------------------------------
1916     /**
1917      * Checks if this date-time is equal to another date-time.
1918      * <p>
1919      * Compares this {@code LocalDateTime} with another ensuring that the date-time is the same.
1920      * Only objects of type {@code LocalDateTime} are compared, other types return false.
1921      *
1922      * @param obj  the object to check, null returns false
1923      * @return true if this is equal to the other date-time
1924      */
1925     @Override
1926     public boolean equals(Object obj) {
1927         if (this == obj) {
1928             return true;
1929         }
1930         if (obj instanceof LocalDateTime) {
1931             LocalDateTime other = (LocalDateTime) obj;
1932             return date.equals(other.date) && time.equals(other.time);
1933         }
1934         return false;
1935     }
1936 
1937     /**
1938      * A hash code for this date-time.
1939      *
1940      * @return a suitable hash code
1941      */
1942     @Override
1943     public int hashCode() {
1944         return date.hashCode() ^ time.hashCode();
1945     }
1946 
1947     //-----------------------------------------------------------------------
1948     /**
1949      * Outputs this date-time as a {@code String}, such as {@code 2007-12-03T10:15:30}.
1950      * <p>
1951      * The output will be one of the following ISO-8601 formats:
1952      * <ul>
1953      * <li>{@code uuuu-MM-dd'T'HH:mm}</li>
1954      * <li>{@code uuuu-MM-dd'T'HH:mm:ss}</li>
1955      * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSS}</li>
1956      * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSSSSS}</li>
1957      * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSSSSSSSS}</li>
1958      * </ul>
1959      * The format used will be the shortest that outputs the full value of
1960      * the time where the omitted parts are implied to be zero.
1961      *
1962      * @return a string representation of this date-time, not null
1963      */
1964     @Override
1965     public String toString() {
1966         return date.toString() + 'T' + time.toString();
1967     }
1968 
1969     //-----------------------------------------------------------------------
1970     /**
1971      * Writes the object using a
1972      * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1973      * @serialData
1974      * <pre>
1975      *  out.writeByte(5);  // identifies a LocalDateTime
1976      *  // the <a href="../../serialized-form.html#java.time.LocalDate">date</a> excluding the one byte header
1977      *  // the <a href="../../serialized-form.html#java.time.LocalTime">time</a> excluding the one byte header
1978      * </pre>
1979      *
1980      * @return the instance of {@code Ser}, not null
1981      */
1982     private Object writeReplace() {
1983         return new Ser(Ser.LOCAL_DATE_TIME_TYPE, this);
1984     }
1985 
1986     /**
1987      * Defend against malicious streams.
1988      *
1989      * @throws InvalidObjectException always
1990      */
1991     private void readObject(ObjectInputStream s) throws InvalidObjectException {
1992         throw new InvalidObjectException("Deserialization via serialization delegate");
1993     }
1994 
1995     void writeExternal(DataOutput out) throws IOException {
1996         date.writeExternal(out);
1997         time.writeExternal(out);
1998     }
1999 
2000     static LocalDateTime readExternal(DataInput in) throws IOException {
2001         LocalDate date = LocalDate.readExternal(in);
2002         LocalTime time = LocalTime.readExternal(in);
2003         return LocalDateTime.of(date, time);
2004     }
2005 
2006 }