1 /*
   2  * Copyright (c) 2012, 2024, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 /*
  27  * This file is available under and governed by the GNU General Public
  28  * License version 2 only, as published by the Free Software Foundation.
  29  * However, the following notice accompanied the original version of this
  30  * file:
  31  *
  32  * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
  33  *
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions are met:
  38  *
  39  *  * Redistributions of source code must retain the above copyright notice,
  40  *    this list of conditions and the following disclaimer.
  41  *
  42  *  * Redistributions in binary form must reproduce the above copyright notice,
  43  *    this list of conditions and the following disclaimer in the documentation
  44  *    and/or other materials provided with the distribution.
  45  *
  46  *  * Neither the name of JSR-310 nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  51  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  52  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  53  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  54  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  55  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  56  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  57  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  58  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  59  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  60  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  61  */
  62 package java.time;
  63 
  64 import static java.time.temporal.ChronoField.INSTANT_SECONDS;
  65 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
  66 import static java.time.temporal.ChronoField.OFFSET_SECONDS;
  67 
  68 import java.io.DataOutput;
  69 import java.io.IOException;
  70 import java.io.ObjectInput;
  71 import java.io.InvalidObjectException;
  72 import java.io.ObjectInputStream;
  73 import java.io.Serializable;
  74 import java.time.chrono.ChronoZonedDateTime;
  75 import java.time.format.DateTimeFormatter;
  76 import java.time.format.DateTimeParseException;
  77 import java.time.temporal.ChronoField;
  78 import java.time.temporal.ChronoUnit;
  79 import java.time.temporal.Temporal;
  80 import java.time.temporal.TemporalAccessor;
  81 import java.time.temporal.TemporalAdjuster;
  82 import java.time.temporal.TemporalAmount;
  83 import java.time.temporal.TemporalField;
  84 import java.time.temporal.TemporalQueries;
  85 import java.time.temporal.TemporalQuery;
  86 import java.time.temporal.TemporalUnit;
  87 import java.time.temporal.UnsupportedTemporalTypeException;
  88 import java.time.temporal.ValueRange;
  89 import java.time.zone.ZoneOffsetTransition;
  90 import java.time.zone.ZoneRules;
  91 import java.util.List;
  92 import java.util.Objects;
  93 
  94 /**
  95  * A date-time with a time-zone in the ISO-8601 calendar system,
  96  * such as {@code 2007-12-03T10:15:30+01:00 Europe/Paris}.
  97  * <p>
  98  * {@code ZonedDateTime} is an immutable representation of a date-time with a time-zone.
  99  * This class stores all date and time fields, to a precision of nanoseconds,
 100  * and a time-zone, with a zone offset used to handle ambiguous local date-times.
 101  * For example, the value
 102  * "2nd October 2007 at 13:45.30.123456789 +02:00 in the Europe/Paris time-zone"
 103  * can be stored in a {@code ZonedDateTime}.
 104  * <p>
 105  * This class handles conversion from the local time-line of {@code LocalDateTime}
 106  * to the instant time-line of {@code Instant}.
 107  * The difference between the two time-lines is the offset from UTC/Greenwich,
 108  * represented by a {@code ZoneOffset}.
 109  * <p>
 110  * Converting between the two time-lines involves calculating the offset using the
 111  * {@link ZoneRules rules} accessed from the {@code ZoneId}.
 112  * Obtaining the offset for an instant is simple, as there is exactly one valid
 113  * offset for each instant. By contrast, obtaining the offset for a local date-time
 114  * is not straightforward. There are three cases:
 115  * <ul>
 116  * <li>Normal, with one valid offset. For the vast majority of the year, the normal
 117  *  case applies, where there is a single valid offset for the local date-time.</li>
 118  * <li>Gap, with zero valid offsets. This is when clocks jump forward typically
 119  *  due to the spring daylight savings change from "winter" to "summer".
 120  *  In a gap there are local date-time values with no valid offset.</li>
 121  * <li>Overlap, with two valid offsets. This is when clocks are set back typically
 122  *  due to the autumn daylight savings change from "summer" to "winter".
 123  *  In an overlap there are local date-time values with two valid offsets.</li>
 124  * </ul>
 125  * <p>
 126  * Any method that converts directly or implicitly from a local date-time to an
 127  * instant by obtaining the offset has the potential to be complicated.
 128  * <p>
 129  * For Gaps, the general strategy is that if the local date-time falls in the
 130  * middle of a Gap, then the resulting zoned date-time will have a local date-time
 131  * shifted forwards by the length of the Gap, resulting in a date-time in the later
 132  * offset, typically "summer" time.
 133  * <p>
 134  * For Overlaps, the general strategy is that if the local date-time falls in the
 135  * middle of an Overlap, then the previous offset will be retained. If there is no
 136  * previous offset, or the previous offset is invalid, then the earlier offset is
 137  * used, typically "summer" time.. Two additional methods,
 138  * {@link #withEarlierOffsetAtOverlap()} and {@link #withLaterOffsetAtOverlap()},
 139  * help manage the case of an overlap.
 140  * <p>
 141  * In terms of design, this class should be viewed primarily as the combination
 142  * of a {@code LocalDateTime} and a {@code ZoneId}. The {@code ZoneOffset} is
 143  * a vital, but secondary, piece of information, used to ensure that the class
 144  * represents an instant, especially during a daylight savings overlap.
 145  * <p>
 146  * This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
 147  * class; programmers should treat instances that are
 148  * {@linkplain #equals(Object) equal} as interchangeable and should not
 149  * use instances for synchronization, or unpredictable behavior may
 150  * occur. For example, in a future release, synchronization may fail.
 151  * The {@code equals} method should be used for comparisons.
 152  *
 153  * @implSpec
 154  * A {@code ZonedDateTime} holds state equivalent to three separate objects,
 155  * a {@code LocalDateTime}, a {@code ZoneId} and the resolved {@code ZoneOffset}.
 156  * The offset and local date-time are used to define an instant when necessary.
 157  * The zone ID is used to obtain the rules for how and when the offset changes.
 158  * The offset cannot be freely set, as the zone controls which offsets are valid.
 159  * <p>
 160  * This class is immutable and thread-safe.
 161  *
 162  * @since 1.8
 163  */
 164 @jdk.internal.ValueBased
 165 @jdk.internal.MigratedValueClass
 166 public final class ZonedDateTime
 167         implements Temporal, ChronoZonedDateTime<LocalDate>, Serializable {
 168 
 169     /**
 170      * Serialization version.
 171      */
 172     @java.io.Serial
 173     private static final long serialVersionUID = -6260982410461394882L;
 174 
 175     /**
 176      * The local date-time.
 177      */
 178     private final LocalDateTime dateTime;
 179     /**
 180      * The offset from UTC/Greenwich.
 181      */
 182     private final ZoneOffset offset;
 183     /**
 184      * The time-zone.
 185      */
 186     private final ZoneId zone;
 187 
 188     //-----------------------------------------------------------------------
 189     /**
 190      * Obtains the current date-time from the system clock in the default time-zone.
 191      * <p>
 192      * This will query the {@link Clock#systemDefaultZone() system clock} in the default
 193      * time-zone to obtain the current date-time.
 194      * The zone and offset will be set based on the time-zone in the clock.
 195      * <p>
 196      * Using this method will prevent the ability to use an alternate clock for testing
 197      * because the clock is hard-coded.
 198      *
 199      * @return the current date-time using the system clock, not null
 200      */
 201     public static ZonedDateTime now() {
 202         return now(Clock.systemDefaultZone());
 203     }
 204 
 205     /**
 206      * Obtains the current date-time from the system clock in the specified time-zone.
 207      * <p>
 208      * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date-time.
 209      * Specifying the time-zone avoids dependence on the default time-zone.
 210      * The offset will be calculated from the specified time-zone.
 211      * <p>
 212      * Using this method will prevent the ability to use an alternate clock for testing
 213      * because the clock is hard-coded.
 214      *
 215      * @param zone  the zone ID to use, not null
 216      * @return the current date-time using the system clock, not null
 217      */
 218     public static ZonedDateTime now(ZoneId zone) {
 219         return now(Clock.system(zone));
 220     }
 221 
 222     /**
 223      * Obtains the current date-time from the specified clock.
 224      * <p>
 225      * This will query the specified clock to obtain the current date-time.
 226      * The zone and offset will be set based on the time-zone in the clock.
 227      * <p>
 228      * Using this method allows the use of an alternate clock for testing.
 229      * The alternate clock may be introduced using {@link Clock dependency injection}.
 230      *
 231      * @param clock  the clock to use, not null
 232      * @return the current date-time, not null
 233      */
 234     public static ZonedDateTime now(Clock clock) {
 235         Objects.requireNonNull(clock, "clock");
 236         final Instant now = clock.instant();  // called once
 237         return ofInstant(now, clock.getZone());
 238     }
 239 
 240     //-----------------------------------------------------------------------
 241     /**
 242      * Obtains an instance of {@code ZonedDateTime} from a local date and time.
 243      * <p>
 244      * This creates a zoned date-time matching the input local date and time as closely as possible.
 245      * Time-zone rules, such as daylight savings, mean that not every local date-time
 246      * is valid for the specified zone, thus the local date-time may be adjusted.
 247      * <p>
 248      * The local date time and first combined to form a local date-time.
 249      * The local date-time is then resolved to a single instant on the time-line.
 250      * This is achieved by finding a valid offset from UTC/Greenwich for the local
 251      * date-time as defined by the {@link ZoneRules rules} of the zone ID.
 252      *<p>
 253      * In most cases, there is only one valid offset for a local date-time.
 254      * In the case of an overlap, when clocks are set back, there are two valid offsets.
 255      * This method uses the earlier offset typically corresponding to "summer".
 256      * <p>
 257      * In the case of a gap, when clocks jump forward, there is no valid offset.
 258      * Instead, the local date-time is adjusted to be later by the length of the gap.
 259      * For a typical one hour daylight savings change, the local date-time will be
 260      * moved one hour later into the offset typically corresponding to "summer".
 261      *
 262      * @param date  the local date, not null
 263      * @param time  the local time, not null
 264      * @param zone  the time-zone, not null
 265      * @return the offset date-time, not null
 266      */
 267     public static ZonedDateTime of(LocalDate date, LocalTime time, ZoneId zone) {
 268         return of(LocalDateTime.of(date, time), zone);
 269     }
 270 
 271     /**
 272      * Obtains an instance of {@code ZonedDateTime} from a local date-time.
 273      * <p>
 274      * This creates a zoned date-time matching the input local date-time as closely as possible.
 275      * Time-zone rules, such as daylight savings, mean that not every local date-time
 276      * is valid for the specified zone, thus the local date-time may be adjusted.
 277      * <p>
 278      * The local date-time is resolved to a single instant on the time-line.
 279      * This is achieved by finding a valid offset from UTC/Greenwich for the local
 280      * date-time as defined by the {@link ZoneRules rules} of the zone ID.
 281      *<p>
 282      * In most cases, there is only one valid offset for a local date-time.
 283      * In the case of an overlap, when clocks are set back, there are two valid offsets.
 284      * This method uses the earlier offset typically corresponding to "summer".
 285      * <p>
 286      * In the case of a gap, when clocks jump forward, there is no valid offset.
 287      * Instead, the local date-time is adjusted to be later by the length of the gap.
 288      * For a typical one hour daylight savings change, the local date-time will be
 289      * moved one hour later into the offset typically corresponding to "summer".
 290      *
 291      * @param localDateTime  the local date-time, not null
 292      * @param zone  the time-zone, not null
 293      * @return the zoned date-time, not null
 294      */
 295     public static ZonedDateTime of(LocalDateTime localDateTime, ZoneId zone) {
 296         return ofLocal(localDateTime, zone, null);
 297     }
 298 
 299     /**
 300      * Obtains an instance of {@code ZonedDateTime} from a year, month, day,
 301      * hour, minute, second, nanosecond and time-zone.
 302      * <p>
 303      * This creates a zoned date-time matching the local date-time of the seven
 304      * specified fields as closely as possible.
 305      * Time-zone rules, such as daylight savings, mean that not every local date-time
 306      * is valid for the specified zone, thus the local date-time may be adjusted.
 307      * <p>
 308      * The local date-time is resolved to a single instant on the time-line.
 309      * This is achieved by finding a valid offset from UTC/Greenwich for the local
 310      * date-time as defined by the {@link ZoneRules rules} of the zone ID.
 311      *<p>
 312      * In most cases, there is only one valid offset for a local date-time.
 313      * In the case of an overlap, when clocks are set back, there are two valid offsets.
 314      * This method uses the earlier offset typically corresponding to "summer".
 315      * <p>
 316      * In the case of a gap, when clocks jump forward, there is no valid offset.
 317      * Instead, the local date-time is adjusted to be later by the length of the gap.
 318      * For a typical one hour daylight savings change, the local date-time will be
 319      * moved one hour later into the offset typically corresponding to "summer".
 320      * <p>
 321      * This method exists primarily for writing test cases.
 322      * Non test-code will typically use other methods to create an offset time.
 323      * {@code LocalDateTime} has five additional convenience variants of the
 324      * equivalent factory method taking fewer arguments.
 325      * They are not provided here to reduce the footprint of the API.
 326      *
 327      * @param year  the year to represent, from MIN_YEAR to MAX_YEAR
 328      * @param month  the month-of-year to represent, from 1 (January) to 12 (December)
 329      * @param dayOfMonth  the day-of-month to represent, from 1 to 31
 330      * @param hour  the hour-of-day to represent, from 0 to 23
 331      * @param minute  the minute-of-hour to represent, from 0 to 59
 332      * @param second  the second-of-minute to represent, from 0 to 59
 333      * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999
 334      * @param zone  the time-zone, not null
 335      * @return the offset date-time, not null
 336      * @throws DateTimeException if the value of any field is out of range, or
 337      *  if the day-of-month is invalid for the month-year
 338      */
 339     public static ZonedDateTime of(
 340             int year, int month, int dayOfMonth,
 341             int hour, int minute, int second, int nanoOfSecond, ZoneId zone) {
 342         LocalDateTime dt = LocalDateTime.of(year, month, dayOfMonth, hour, minute, second, nanoOfSecond);
 343         return ofLocal(dt, zone, null);
 344     }
 345 
 346     /**
 347      * Obtains an instance of {@code ZonedDateTime} from a local date-time
 348      * using the preferred offset if possible.
 349      * <p>
 350      * The local date-time is resolved to a single instant on the time-line.
 351      * This is achieved by finding a valid offset from UTC/Greenwich for the local
 352      * date-time as defined by the {@link ZoneRules rules} of the zone ID.
 353      *<p>
 354      * In most cases, there is only one valid offset for a local date-time.
 355      * In the case of an overlap, where clocks are set back, there are two valid offsets.
 356      * If the preferred offset is one of the valid offsets then it is used.
 357      * Otherwise the earlier valid offset is used, typically corresponding to "summer".
 358      * <p>
 359      * In the case of a gap, where clocks jump forward, there is no valid offset.
 360      * Instead, the local date-time is adjusted to be later by the length of the gap.
 361      * For a typical one hour daylight savings change, the local date-time will be
 362      * moved one hour later into the offset typically corresponding to "summer".
 363      *
 364      * @param localDateTime  the local date-time, not null
 365      * @param zone  the time-zone, not null
 366      * @param preferredOffset  the zone offset, null if no preference
 367      * @return the zoned date-time, not null
 368      */
 369     public static ZonedDateTime ofLocal(LocalDateTime localDateTime, ZoneId zone, ZoneOffset preferredOffset) {
 370         Objects.requireNonNull(localDateTime, "localDateTime");
 371         Objects.requireNonNull(zone, "zone");
 372         if (zone instanceof ZoneOffset) {
 373             return new ZonedDateTime(localDateTime, (ZoneOffset) zone, zone);
 374         }
 375         ZoneRules rules = zone.getRules();
 376         List<ZoneOffset> validOffsets = rules.getValidOffsets(localDateTime);
 377         ZoneOffset offset;
 378         if (validOffsets.size() == 1) {
 379             offset = validOffsets.get(0);
 380         } else if (validOffsets.size() == 0) {
 381             ZoneOffsetTransition trans = rules.getTransition(localDateTime);
 382             localDateTime = localDateTime.plusSeconds(trans.getDuration().getSeconds());
 383             offset = trans.getOffsetAfter();
 384         } else {
 385             if (preferredOffset != null && validOffsets.contains(preferredOffset)) {
 386                 offset = preferredOffset;
 387             } else {
 388                 offset = Objects.requireNonNull(validOffsets.get(0), "offset");  // protect against bad ZoneRules
 389             }
 390         }
 391         return new ZonedDateTime(localDateTime, offset, zone);
 392     }
 393 
 394     //-----------------------------------------------------------------------
 395     /**
 396      * Obtains an instance of {@code ZonedDateTime} from an {@code Instant}.
 397      * <p>
 398      * This creates a zoned date-time with the same instant as that specified.
 399      * Calling {@link #toInstant()} will return an instant equal to the one used here.
 400      * <p>
 401      * Converting an instant to a zoned date-time is simple as there is only one valid
 402      * offset for each instant.
 403      *
 404      * @param instant  the instant to create the date-time from, not null
 405      * @param zone  the time-zone, not null
 406      * @return the zoned date-time, not null
 407      * @throws DateTimeException if the result exceeds the supported range
 408      */
 409     public static ZonedDateTime ofInstant(Instant instant, ZoneId zone) {
 410         Objects.requireNonNull(instant, "instant");
 411         Objects.requireNonNull(zone, "zone");
 412         return create(instant.getEpochSecond(), instant.getNano(), zone);
 413     }
 414 
 415     /**
 416      * Obtains an instance of {@code ZonedDateTime} from the instant formed by combining
 417      * the local date-time and offset.
 418      * <p>
 419      * This creates a zoned date-time by {@link LocalDateTime#toInstant(ZoneOffset) combining}
 420      * the {@code LocalDateTime} and {@code ZoneOffset}.
 421      * This combination uniquely specifies an instant without ambiguity.
 422      * <p>
 423      * Converting an instant to a zoned date-time is simple as there is only one valid
 424      * offset for each instant. If the valid offset is different to the offset specified,
 425      * then the date-time and offset of the zoned date-time will differ from those specified.
 426      * <p>
 427      * If the {@code ZoneId} to be used is a {@code ZoneOffset}, this method is equivalent
 428      * to {@link #of(LocalDateTime, ZoneId)}.
 429      *
 430      * @param localDateTime  the local date-time, not null
 431      * @param offset  the zone offset, not null
 432      * @param zone  the time-zone, not null
 433      * @return the zoned date-time, not null
 434      */
 435     public static ZonedDateTime ofInstant(LocalDateTime localDateTime, ZoneOffset offset, ZoneId zone) {
 436         Objects.requireNonNull(localDateTime, "localDateTime");
 437         Objects.requireNonNull(offset, "offset");
 438         Objects.requireNonNull(zone, "zone");
 439         if (zone.getRules().isValidOffset(localDateTime, offset)) {
 440             return new ZonedDateTime(localDateTime, offset, zone);
 441         }
 442         return create(localDateTime.toEpochSecond(offset), localDateTime.getNano(), zone);
 443     }
 444 
 445     /**
 446      * Obtains an instance of {@code ZonedDateTime} using seconds from the
 447      * epoch of 1970-01-01T00:00:00Z.
 448      *
 449      * @param epochSecond  the number of seconds from the epoch of 1970-01-01T00:00:00Z
 450      * @param nanoOfSecond  the nanosecond within the second, from 0 to 999,999,999
 451      * @param zone  the time-zone, not null
 452      * @return the zoned date-time, not null
 453      * @throws DateTimeException if the result exceeds the supported range
 454      */
 455     private static ZonedDateTime create(long epochSecond, int nanoOfSecond, ZoneId zone) {
 456         // nanoOfSecond is in a range that'll not affect epochSecond, validated
 457         // by LocalDateTime.ofEpochSecond
 458         ZoneOffset offset = zone.getOffset(epochSecond);
 459         LocalDateTime ldt = LocalDateTime.ofEpochSecond(epochSecond, nanoOfSecond, offset);
 460         return new ZonedDateTime(ldt, offset, zone);
 461     }
 462 
 463     //-----------------------------------------------------------------------
 464     /**
 465      * Obtains an instance of {@code ZonedDateTime} strictly validating the
 466      * combination of local date-time, offset and zone ID.
 467      * <p>
 468      * This creates a zoned date-time ensuring that the offset is valid for the
 469      * local date-time according to the rules of the specified zone.
 470      * If the offset is invalid, an exception is thrown.
 471      *
 472      * @param localDateTime  the local date-time, not null
 473      * @param offset  the zone offset, not null
 474      * @param zone  the time-zone, not null
 475      * @return the zoned date-time, not null
 476      * @throws DateTimeException if the combination of arguments is invalid
 477      */
 478     public static ZonedDateTime ofStrict(LocalDateTime localDateTime, ZoneOffset offset, ZoneId zone) {
 479         Objects.requireNonNull(localDateTime, "localDateTime");
 480         Objects.requireNonNull(offset, "offset");
 481         Objects.requireNonNull(zone, "zone");
 482         ZoneRules rules = zone.getRules();
 483         if (rules.isValidOffset(localDateTime, offset) == false) {
 484             ZoneOffsetTransition trans = rules.getTransition(localDateTime);
 485             if (trans != null && trans.isGap()) {
 486                 // error message says daylight savings for simplicity
 487                 // even though there are other kinds of gaps
 488                 throw new DateTimeException("LocalDateTime '" + localDateTime +
 489                         "' does not exist in zone '" + zone +
 490                         "' due to a gap in the local time-line, typically caused by daylight savings");
 491             }
 492             throw new DateTimeException("ZoneOffset '" + offset + "' is not valid for LocalDateTime '" +
 493                     localDateTime + "' in zone '" + zone + "'");
 494         }
 495         return new ZonedDateTime(localDateTime, offset, zone);
 496     }
 497 
 498     /**
 499      * Obtains an instance of {@code ZonedDateTime} leniently, for advanced use cases,
 500      * allowing any combination of local date-time, offset and zone ID.
 501      * <p>
 502      * This creates a zoned date-time with no checks other than no nulls.
 503      * This means that the resulting zoned date-time may have an offset that is in conflict
 504      * with the zone ID.
 505      * <p>
 506      * This method is intended for advanced use cases.
 507      * For example, consider the case where a zoned date-time with valid fields is created
 508      * and then stored in a database or serialization-based store. At some later point,
 509      * the object is then re-loaded. However, between those points in time, the government
 510      * that defined the time-zone has changed the rules, such that the originally stored
 511      * local date-time now does not occur. This method can be used to create the object
 512      * in an "invalid" state, despite the change in rules.
 513      *
 514      * @param localDateTime  the local date-time, not null
 515      * @param offset  the zone offset, not null
 516      * @param zone  the time-zone, not null
 517      * @return the zoned date-time, not null
 518      */
 519     private static ZonedDateTime ofLenient(LocalDateTime localDateTime, ZoneOffset offset, ZoneId zone) {
 520         Objects.requireNonNull(localDateTime, "localDateTime");
 521         Objects.requireNonNull(offset, "offset");
 522         Objects.requireNonNull(zone, "zone");
 523         if (zone instanceof ZoneOffset && offset.equals(zone) == false) {
 524             throw new IllegalArgumentException("ZoneId must match ZoneOffset");
 525         }
 526         return new ZonedDateTime(localDateTime, offset, zone);
 527     }
 528 
 529     //-----------------------------------------------------------------------
 530     /**
 531      * Obtains an instance of {@code ZonedDateTime} from a temporal object.
 532      * <p>
 533      * This obtains a zoned date-time based on the specified temporal.
 534      * A {@code TemporalAccessor} represents an arbitrary set of date and time information,
 535      * which this factory converts to an instance of {@code ZonedDateTime}.
 536      * <p>
 537      * The conversion will first obtain a {@code ZoneId} from the temporal object,
 538      * falling back to a {@code ZoneOffset} if necessary. It will then try to obtain
 539      * an {@code Instant}, falling back to a {@code LocalDateTime} if necessary.
 540      * The result will be either the combination of {@code ZoneId} or {@code ZoneOffset}
 541      * with {@code Instant} or {@code LocalDateTime}.
 542      * Implementations are permitted to perform optimizations such as accessing
 543      * those fields that are equivalent to the relevant objects.
 544      * <p>
 545      * This method matches the signature of the functional interface {@link TemporalQuery}
 546      * allowing it to be used as a query via method reference, {@code ZonedDateTime::from}.
 547      *
 548      * @param temporal  the temporal object to convert, not null
 549      * @return the zoned date-time, not null
 550      * @throws DateTimeException if unable to convert to an {@code ZonedDateTime}
 551      */
 552     public static ZonedDateTime from(TemporalAccessor temporal) {
 553         if (temporal instanceof ZonedDateTime) {
 554             return (ZonedDateTime) temporal;
 555         }
 556         try {
 557             ZoneId zone = ZoneId.from(temporal);
 558             if (temporal.isSupported(INSTANT_SECONDS)) {
 559                 long epochSecond = temporal.getLong(INSTANT_SECONDS);
 560                 int nanoOfSecond = temporal.get(NANO_OF_SECOND);
 561                 return create(epochSecond, nanoOfSecond, zone);
 562             } else {
 563                 LocalDate date = LocalDate.from(temporal);
 564                 LocalTime time = LocalTime.from(temporal);
 565                 return of(date, time, zone);
 566             }
 567         } catch (DateTimeException ex) {
 568             throw new DateTimeException("Unable to obtain ZonedDateTime from TemporalAccessor: " +
 569                     temporal + " of type " + temporal.getClass().getName(), ex);
 570         }
 571     }
 572 
 573     //-----------------------------------------------------------------------
 574     /**
 575      * Obtains an instance of {@code ZonedDateTime} from a text string such as
 576      * {@code 2007-12-03T10:15:30+01:00[Europe/Paris]}.
 577      * <p>
 578      * The string must represent a valid date-time and is parsed using
 579      * {@link java.time.format.DateTimeFormatter#ISO_ZONED_DATE_TIME}.
 580      *
 581      * @param text  the text to parse such as "2007-12-03T10:15:30+01:00[Europe/Paris]", not null
 582      * @return the parsed zoned date-time, not null
 583      * @throws DateTimeParseException if the text cannot be parsed
 584      */
 585     public static ZonedDateTime parse(CharSequence text) {
 586         return parse(text, DateTimeFormatter.ISO_ZONED_DATE_TIME);
 587     }
 588 
 589     /**
 590      * Obtains an instance of {@code ZonedDateTime} from a text string using a specific formatter.
 591      * <p>
 592      * The text is parsed using the formatter, returning a date-time.
 593      *
 594      * @param text  the text to parse, not null
 595      * @param formatter  the formatter to use, not null
 596      * @return the parsed zoned date-time, not null
 597      * @throws DateTimeParseException if the text cannot be parsed
 598      */
 599     public static ZonedDateTime parse(CharSequence text, DateTimeFormatter formatter) {
 600         Objects.requireNonNull(formatter, "formatter");
 601         return formatter.parse(text, ZonedDateTime::from);
 602     }
 603 
 604     //-----------------------------------------------------------------------
 605     /**
 606      * Constructor.
 607      *
 608      * @param dateTime  the date-time, validated as not null
 609      * @param offset  the zone offset, validated as not null
 610      * @param zone  the time-zone, validated as not null
 611      */
 612     private ZonedDateTime(LocalDateTime dateTime, ZoneOffset offset, ZoneId zone) {
 613         this.dateTime = dateTime;
 614         this.offset = offset;
 615         this.zone = zone;
 616     }
 617 
 618     /**
 619      * Resolves the new local date-time using this zone ID, retaining the offset if possible.
 620      *
 621      * @param newDateTime  the new local date-time, not null
 622      * @return the zoned date-time, not null
 623      */
 624     private ZonedDateTime resolveLocal(LocalDateTime newDateTime) {
 625         return ofLocal(newDateTime, zone, offset);
 626     }
 627 
 628     /**
 629      * Resolves the new local date-time using the offset to identify the instant.
 630      *
 631      * @param newDateTime  the new local date-time, not null
 632      * @return the zoned date-time, not null
 633      */
 634     private ZonedDateTime resolveInstant(LocalDateTime newDateTime) {
 635         return ofInstant(newDateTime, offset, zone);
 636     }
 637 
 638     /**
 639      * Resolves the offset into this zoned date-time for the with methods.
 640      * <p>
 641      * This typically ignores the offset, unless it can be used to switch offset in a DST overlap.
 642      *
 643      * @param offset  the offset, not null
 644      * @return the zoned date-time, not null
 645      */
 646     private ZonedDateTime resolveOffset(ZoneOffset offset) {
 647         if (offset.equals(this.offset) == false && zone.getRules().isValidOffset(dateTime, offset)) {
 648             return new ZonedDateTime(dateTime, offset, zone);
 649         }
 650         return this;
 651     }
 652 
 653     //-----------------------------------------------------------------------
 654     /**
 655      * Checks if the specified field is supported.
 656      * <p>
 657      * This checks if this date-time can be queried for the specified field.
 658      * If false, then calling the {@link #range(TemporalField) range},
 659      * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
 660      * methods will throw an exception.
 661      * <p>
 662      * If the field is a {@link ChronoField} then the query is implemented here.
 663      * The supported fields are:
 664      * <ul>
 665      * <li>{@code NANO_OF_SECOND}
 666      * <li>{@code NANO_OF_DAY}
 667      * <li>{@code MICRO_OF_SECOND}
 668      * <li>{@code MICRO_OF_DAY}
 669      * <li>{@code MILLI_OF_SECOND}
 670      * <li>{@code MILLI_OF_DAY}
 671      * <li>{@code SECOND_OF_MINUTE}
 672      * <li>{@code SECOND_OF_DAY}
 673      * <li>{@code MINUTE_OF_HOUR}
 674      * <li>{@code MINUTE_OF_DAY}
 675      * <li>{@code HOUR_OF_AMPM}
 676      * <li>{@code CLOCK_HOUR_OF_AMPM}
 677      * <li>{@code HOUR_OF_DAY}
 678      * <li>{@code CLOCK_HOUR_OF_DAY}
 679      * <li>{@code AMPM_OF_DAY}
 680      * <li>{@code DAY_OF_WEEK}
 681      * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
 682      * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
 683      * <li>{@code DAY_OF_MONTH}
 684      * <li>{@code DAY_OF_YEAR}
 685      * <li>{@code EPOCH_DAY}
 686      * <li>{@code ALIGNED_WEEK_OF_MONTH}
 687      * <li>{@code ALIGNED_WEEK_OF_YEAR}
 688      * <li>{@code MONTH_OF_YEAR}
 689      * <li>{@code PROLEPTIC_MONTH}
 690      * <li>{@code YEAR_OF_ERA}
 691      * <li>{@code YEAR}
 692      * <li>{@code ERA}
 693      * <li>{@code INSTANT_SECONDS}
 694      * <li>{@code OFFSET_SECONDS}
 695      * </ul>
 696      * All other {@code ChronoField} instances will return false.
 697      * <p>
 698      * If the field is not a {@code ChronoField}, then the result of this method
 699      * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
 700      * passing {@code this} as the argument.
 701      * Whether the field is supported is determined by the field.
 702      *
 703      * @param field  the field to check, null returns false
 704      * @return true if the field is supported on this date-time, false if not
 705      */
 706     @Override
 707     public boolean isSupported(TemporalField field) {
 708         return field instanceof ChronoField || (field != null && field.isSupportedBy(this));
 709     }
 710 
 711     /**
 712      * Checks if the specified unit is supported.
 713      * <p>
 714      * This checks if the specified unit can be added to, or subtracted from, this date-time.
 715      * If false, then calling the {@link #plus(long, TemporalUnit)} and
 716      * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
 717      * <p>
 718      * If the unit is a {@link ChronoUnit} then the query is implemented here.
 719      * The supported units are:
 720      * <ul>
 721      * <li>{@code NANOS}
 722      * <li>{@code MICROS}
 723      * <li>{@code MILLIS}
 724      * <li>{@code SECONDS}
 725      * <li>{@code MINUTES}
 726      * <li>{@code HOURS}
 727      * <li>{@code HALF_DAYS}
 728      * <li>{@code DAYS}
 729      * <li>{@code WEEKS}
 730      * <li>{@code MONTHS}
 731      * <li>{@code YEARS}
 732      * <li>{@code DECADES}
 733      * <li>{@code CENTURIES}
 734      * <li>{@code MILLENNIA}
 735      * <li>{@code ERAS}
 736      * </ul>
 737      * All other {@code ChronoUnit} instances will return false.
 738      * <p>
 739      * If the unit is not a {@code ChronoUnit}, then the result of this method
 740      * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
 741      * passing {@code this} as the argument.
 742      * Whether the unit is supported is determined by the unit.
 743      *
 744      * @param unit  the unit to check, null returns false
 745      * @return true if the unit can be added/subtracted, false if not
 746      */
 747     @Override  // override for Javadoc
 748     public boolean isSupported(TemporalUnit unit) {
 749         return ChronoZonedDateTime.super.isSupported(unit);
 750     }
 751 
 752     //-----------------------------------------------------------------------
 753     /**
 754      * Gets the range of valid values for the specified field.
 755      * <p>
 756      * The range object expresses the minimum and maximum valid values for a field.
 757      * This date-time is used to enhance the accuracy of the returned range.
 758      * If it is not possible to return the range, because the field is not supported
 759      * or for some other reason, an exception is thrown.
 760      * <p>
 761      * If the field is a {@link ChronoField} then the query is implemented here.
 762      * The {@link #isSupported(TemporalField) supported fields} will return
 763      * appropriate range instances.
 764      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 765      * <p>
 766      * If the field is not a {@code ChronoField}, then the result of this method
 767      * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
 768      * passing {@code this} as the argument.
 769      * Whether the range can be obtained is determined by the field.
 770      *
 771      * @param field  the field to query the range for, not null
 772      * @return the range of valid values for the field, not null
 773      * @throws DateTimeException if the range for the field cannot be obtained
 774      * @throws UnsupportedTemporalTypeException if the field is not supported
 775      */
 776     @Override
 777     public ValueRange range(TemporalField field) {
 778         if (field instanceof ChronoField) {
 779             if (field == INSTANT_SECONDS || field == OFFSET_SECONDS) {
 780                 return field.range();
 781             }
 782             return dateTime.range(field);
 783         }
 784         return field.rangeRefinedBy(this);
 785     }
 786 
 787     /**
 788      * Gets the value of the specified field from this date-time as an {@code int}.
 789      * <p>
 790      * This queries this date-time for the value of the specified field.
 791      * The returned value will always be within the valid range of values for the field.
 792      * If it is not possible to return the value, because the field is not supported
 793      * or for some other reason, an exception is thrown.
 794      * <p>
 795      * If the field is a {@link ChronoField} then the query is implemented here.
 796      * The {@link #isSupported(TemporalField) supported fields} will return valid
 797      * values based on this date-time, except {@code NANO_OF_DAY}, {@code MICRO_OF_DAY},
 798      * {@code EPOCH_DAY}, {@code PROLEPTIC_MONTH} and {@code INSTANT_SECONDS} which are too
 799      * large to fit in an {@code int} and throw an {@code UnsupportedTemporalTypeException}.
 800      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 801      * <p>
 802      * If the field is not a {@code ChronoField}, then the result of this method
 803      * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
 804      * passing {@code this} as the argument. Whether the value can be obtained,
 805      * and what the value represents, is determined by the field.
 806      *
 807      * @param field  the field to get, not null
 808      * @return the value for the field
 809      * @throws DateTimeException if a value for the field cannot be obtained or
 810      *         the value is outside the range of valid values for the field
 811      * @throws UnsupportedTemporalTypeException if the field is not supported or
 812      *         the range of values exceeds an {@code int}
 813      * @throws ArithmeticException if numeric overflow occurs
 814      */
 815     @Override  // override for Javadoc and performance
 816     public int get(TemporalField field) {
 817         if (field instanceof ChronoField chronoField) {
 818             return switch (chronoField) {
 819                 case INSTANT_SECONDS -> throw new UnsupportedTemporalTypeException("Invalid field " +
 820                                          "'InstantSeconds' for get() method, use getLong() instead");
 821                 case OFFSET_SECONDS -> getOffset().getTotalSeconds();
 822                 default -> dateTime.get(field);
 823             };
 824         }
 825         return ChronoZonedDateTime.super.get(field);
 826     }
 827 
 828     /**
 829      * Gets the value of the specified field from this date-time as a {@code long}.
 830      * <p>
 831      * This queries this date-time for the value of the specified field.
 832      * If it is not possible to return the value, because the field is not supported
 833      * or for some other reason, an exception is thrown.
 834      * <p>
 835      * If the field is a {@link ChronoField} then the query is implemented here.
 836      * The {@link #isSupported(TemporalField) supported fields} will return valid
 837      * values based on this date-time.
 838      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 839      * <p>
 840      * If the field is not a {@code ChronoField}, then the result of this method
 841      * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
 842      * passing {@code this} as the argument. Whether the value can be obtained,
 843      * and what the value represents, is determined by the field.
 844      *
 845      * @param field  the field to get, not null
 846      * @return the value for the field
 847      * @throws DateTimeException if a value for the field cannot be obtained
 848      * @throws UnsupportedTemporalTypeException if the field is not supported
 849      * @throws ArithmeticException if numeric overflow occurs
 850      */
 851     @Override
 852     public long getLong(TemporalField field) {
 853         if (field instanceof ChronoField chronoField) {
 854             return switch (chronoField) {
 855                 case INSTANT_SECONDS -> toEpochSecond();
 856                 case OFFSET_SECONDS -> getOffset().getTotalSeconds();
 857                 default -> dateTime.getLong(field);
 858             };
 859         }
 860         return field.getFrom(this);
 861     }
 862 
 863     //-----------------------------------------------------------------------
 864     /**
 865      * Gets the zone offset, such as '+01:00'.
 866      * <p>
 867      * This is the offset of the local date-time from UTC/Greenwich.
 868      *
 869      * @return the zone offset, not null
 870      */
 871     @Override
 872     public ZoneOffset getOffset() {
 873         return offset;
 874     }
 875 
 876     /**
 877      * Returns a copy of this date-time changing the zone offset to the
 878      * earlier of the two valid offsets at a local time-line overlap.
 879      * <p>
 880      * This method only has any effect when the local time-line overlaps, such as
 881      * at an autumn daylight savings cutover. In this scenario, there are two
 882      * valid offsets for the local date-time. Calling this method will return
 883      * a zoned date-time with the earlier of the two selected.
 884      * <p>
 885      * If this method is called when it is not an overlap, {@code this}
 886      * is returned.
 887      * <p>
 888      * This instance is immutable and unaffected by this method call.
 889      *
 890      * @return a {@code ZonedDateTime} based on this date-time with the earlier offset, not null
 891      */
 892     @Override
 893     public ZonedDateTime withEarlierOffsetAtOverlap() {
 894         ZoneOffsetTransition trans = getZone().getRules().getTransition(dateTime);
 895         if (trans != null && trans.isOverlap()) {
 896             ZoneOffset earlierOffset = trans.getOffsetBefore();
 897             if (earlierOffset.equals(offset) == false) {
 898                 return new ZonedDateTime(dateTime, earlierOffset, zone);
 899             }
 900         }
 901         return this;
 902     }
 903 
 904     /**
 905      * Returns a copy of this date-time changing the zone offset to the
 906      * later of the two valid offsets at a local time-line overlap.
 907      * <p>
 908      * This method only has any effect when the local time-line overlaps, such as
 909      * at an autumn daylight savings cutover. In this scenario, there are two
 910      * valid offsets for the local date-time. Calling this method will return
 911      * a zoned date-time with the later of the two selected.
 912      * <p>
 913      * If this method is called when it is not an overlap, {@code this}
 914      * is returned.
 915      * <p>
 916      * This instance is immutable and unaffected by this method call.
 917      *
 918      * @return a {@code ZonedDateTime} based on this date-time with the later offset, not null
 919      */
 920     @Override
 921     public ZonedDateTime withLaterOffsetAtOverlap() {
 922         ZoneOffsetTransition trans = getZone().getRules().getTransition(toLocalDateTime());
 923         if (trans != null) {
 924             ZoneOffset laterOffset = trans.getOffsetAfter();
 925             if (laterOffset.equals(offset) == false) {
 926                 return new ZonedDateTime(dateTime, laterOffset, zone);
 927             }
 928         }
 929         return this;
 930     }
 931 
 932     //-----------------------------------------------------------------------
 933     /**
 934      * Gets the time-zone, such as 'Europe/Paris'.
 935      * <p>
 936      * This returns the zone ID. This identifies the time-zone {@link ZoneRules rules}
 937      * that determine when and how the offset from UTC/Greenwich changes.
 938      * <p>
 939      * The zone ID may be same as the {@linkplain #getOffset() offset}.
 940      * If this is true, then any future calculations, such as addition or subtraction,
 941      * have no complex edge cases due to time-zone rules.
 942      * See also {@link #withFixedOffsetZone()}.
 943      *
 944      * @return the time-zone, not null
 945      */
 946     @Override
 947     public ZoneId getZone() {
 948         return zone;
 949     }
 950 
 951     /**
 952      * Returns a copy of this date-time with a different time-zone,
 953      * retaining the local date-time if possible.
 954      * <p>
 955      * This method changes the time-zone and retains the local date-time.
 956      * The local date-time is only changed if it is invalid for the new zone,
 957      * determined using the same approach as
 958      * {@link #ofLocal(LocalDateTime, ZoneId, ZoneOffset)}.
 959      * <p>
 960      * To change the zone and adjust the local date-time,
 961      * use {@link #withZoneSameInstant(ZoneId)}.
 962      * <p>
 963      * This instance is immutable and unaffected by this method call.
 964      *
 965      * @param zone  the time-zone to change to, not null
 966      * @return a {@code ZonedDateTime} based on this date-time with the requested zone, not null
 967      */
 968     @Override
 969     public ZonedDateTime withZoneSameLocal(ZoneId zone) {
 970         Objects.requireNonNull(zone, "zone");
 971         return this.zone.equals(zone) ? this : ofLocal(dateTime, zone, offset);
 972     }
 973 
 974     /**
 975      * Returns a copy of this date-time with a different time-zone,
 976      * retaining the instant.
 977      * <p>
 978      * This method changes the time-zone and retains the instant.
 979      * This normally results in a change to the local date-time.
 980      * <p>
 981      * This method is based on retaining the same instant, thus gaps and overlaps
 982      * in the local time-line have no effect on the result.
 983      * <p>
 984      * To change the offset while keeping the local time,
 985      * use {@link #withZoneSameLocal(ZoneId)}.
 986      *
 987      * @param zone  the time-zone to change to, not null
 988      * @return a {@code ZonedDateTime} based on this date-time with the requested zone, not null
 989      * @throws DateTimeException if the result exceeds the supported date range
 990      */
 991     @Override
 992     public ZonedDateTime withZoneSameInstant(ZoneId zone) {
 993         Objects.requireNonNull(zone, "zone");
 994         return this.zone.equals(zone) ? this :
 995             create(dateTime.toEpochSecond(offset), dateTime.getNano(), zone);
 996     }
 997 
 998     /**
 999      * Returns a copy of this date-time with the zone ID set to the offset.
1000      * <p>
1001      * This returns a zoned date-time where the zone ID is the same as {@link #getOffset()}.
1002      * The local date-time, offset and instant of the result will be the same as in this date-time.
1003      * <p>
1004      * Setting the date-time to a fixed single offset means that any future
1005      * calculations, such as addition or subtraction, have no complex edge cases
1006      * due to time-zone rules.
1007      * This might also be useful when sending a zoned date-time across a network,
1008      * as most protocols, such as ISO-8601, only handle offsets,
1009      * and not region-based zone IDs.
1010      * <p>
1011      * This is equivalent to {@code ZonedDateTime.of(zdt.toLocalDateTime(), zdt.getOffset())}.
1012      *
1013      * @return a {@code ZonedDateTime} with the zone ID set to the offset, not null
1014      */
1015     public ZonedDateTime withFixedOffsetZone() {
1016         return this.zone.equals(offset) ? this : new ZonedDateTime(dateTime, offset, offset);
1017     }
1018 
1019     //-----------------------------------------------------------------------
1020     /**
1021      * Gets the {@code LocalDateTime} part of this date-time.
1022      * <p>
1023      * This returns a {@code LocalDateTime} with the same year, month, day and time
1024      * as this date-time.
1025      *
1026      * @return the local date-time part of this date-time, not null
1027      */
1028     @Override  // override for return type
1029     public LocalDateTime toLocalDateTime() {
1030         return dateTime;
1031     }
1032 
1033     //-----------------------------------------------------------------------
1034     /**
1035      * Gets the {@code LocalDate} part of this date-time.
1036      * <p>
1037      * This returns a {@code LocalDate} with the same year, month and day
1038      * as this date-time.
1039      *
1040      * @return the date part of this date-time, not null
1041      */
1042     @Override  // override for return type
1043     public LocalDate toLocalDate() {
1044         return dateTime.toLocalDate();
1045     }
1046 
1047     /**
1048      * Gets the year field.
1049      * <p>
1050      * This method returns the primitive {@code int} value for the year.
1051      * <p>
1052      * The year returned by this method is proleptic as per {@code get(YEAR)}.
1053      * To obtain the year-of-era, use {@code get(YEAR_OF_ERA)}.
1054      *
1055      * @return the year, from MIN_YEAR to MAX_YEAR
1056      */
1057     public int getYear() {
1058         return dateTime.getYear();
1059     }
1060 
1061     /**
1062      * Gets the month-of-year field from 1 to 12.
1063      * <p>
1064      * This method returns the month as an {@code int} from 1 to 12.
1065      * Application code is frequently clearer if the enum {@link Month}
1066      * is used by calling {@link #getMonth()}.
1067      *
1068      * @return the month-of-year, from 1 to 12
1069      * @see #getMonth()
1070      */
1071     public int getMonthValue() {
1072         return dateTime.getMonthValue();
1073     }
1074 
1075     /**
1076      * Gets the month-of-year field using the {@code Month} enum.
1077      * <p>
1078      * This method returns the enum {@link Month} for the month.
1079      * This avoids confusion as to what {@code int} values mean.
1080      * If you need access to the primitive {@code int} value then the enum
1081      * provides the {@link Month#getValue() int value}.
1082      *
1083      * @return the month-of-year, not null
1084      * @see #getMonthValue()
1085      */
1086     public Month getMonth() {
1087         return dateTime.getMonth();
1088     }
1089 
1090     /**
1091      * Gets the day-of-month field.
1092      * <p>
1093      * This method returns the primitive {@code int} value for the day-of-month.
1094      *
1095      * @return the day-of-month, from 1 to 31
1096      */
1097     public int getDayOfMonth() {
1098         return dateTime.getDayOfMonth();
1099     }
1100 
1101     /**
1102      * Gets the day-of-year field.
1103      * <p>
1104      * This method returns the primitive {@code int} value for the day-of-year.
1105      *
1106      * @return the day-of-year, from 1 to 365, or 366 in a leap year
1107      */
1108     public int getDayOfYear() {
1109         return dateTime.getDayOfYear();
1110     }
1111 
1112     /**
1113      * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
1114      * <p>
1115      * This method returns the enum {@link DayOfWeek} for the day-of-week.
1116      * This avoids confusion as to what {@code int} values mean.
1117      * If you need access to the primitive {@code int} value then the enum
1118      * provides the {@link DayOfWeek#getValue() int value}.
1119      * <p>
1120      * Additional information can be obtained from the {@code DayOfWeek}.
1121      * This includes textual names of the values.
1122      *
1123      * @return the day-of-week, not null
1124      */
1125     public DayOfWeek getDayOfWeek() {
1126         return dateTime.getDayOfWeek();
1127     }
1128 
1129     //-----------------------------------------------------------------------
1130     /**
1131      * Gets the {@code LocalTime} part of this date-time.
1132      * <p>
1133      * This returns a {@code LocalTime} with the same hour, minute, second and
1134      * nanosecond as this date-time.
1135      *
1136      * @return the time part of this date-time, not null
1137      */
1138     @Override  // override for Javadoc and performance
1139     public LocalTime toLocalTime() {
1140         return dateTime.toLocalTime();
1141     }
1142 
1143     /**
1144      * Gets the hour-of-day field.
1145      *
1146      * @return the hour-of-day, from 0 to 23
1147      */
1148     public int getHour() {
1149         return dateTime.getHour();
1150     }
1151 
1152     /**
1153      * Gets the minute-of-hour field.
1154      *
1155      * @return the minute-of-hour, from 0 to 59
1156      */
1157     public int getMinute() {
1158         return dateTime.getMinute();
1159     }
1160 
1161     /**
1162      * Gets the second-of-minute field.
1163      *
1164      * @return the second-of-minute, from 0 to 59
1165      */
1166     public int getSecond() {
1167         return dateTime.getSecond();
1168     }
1169 
1170     /**
1171      * Gets the nano-of-second field.
1172      *
1173      * @return the nano-of-second, from 0 to 999,999,999
1174      */
1175     public int getNano() {
1176         return dateTime.getNano();
1177     }
1178 
1179     //-----------------------------------------------------------------------
1180     /**
1181      * Returns an adjusted copy of this date-time.
1182      * <p>
1183      * This returns a {@code ZonedDateTime}, based on this one, with the date-time adjusted.
1184      * The adjustment takes place using the specified adjuster strategy object.
1185      * Read the documentation of the adjuster to understand what adjustment will be made.
1186      * <p>
1187      * A simple adjuster might simply set the one of the fields, such as the year field.
1188      * A more complex adjuster might set the date to the last day of the month.
1189      * A selection of common adjustments is provided in
1190      * {@link java.time.temporal.TemporalAdjusters TemporalAdjusters}.
1191      * These include finding the "last day of the month" and "next Wednesday".
1192      * Key date-time classes also implement the {@code TemporalAdjuster} interface,
1193      * such as {@link Month} and {@link java.time.MonthDay MonthDay}.
1194      * The adjuster is responsible for handling special cases, such as the varying
1195      * lengths of month and leap years.
1196      * <p>
1197      * For example this code returns a date on the last day of July:
1198      * <pre>
1199      *  import static java.time.Month.*;
1200      *  import static java.time.temporal.TemporalAdjusters.*;
1201      *
1202      *  result = zonedDateTime.with(JULY).with(lastDayOfMonth());
1203      * </pre>
1204      * <p>
1205      * The classes {@link LocalDate} and {@link LocalTime} implement {@code TemporalAdjuster},
1206      * thus this method can be used to change the date, time or offset:
1207      * <pre>
1208      *  result = zonedDateTime.with(date);
1209      *  result = zonedDateTime.with(time);
1210      * </pre>
1211      * <p>
1212      * {@link ZoneOffset} also implements {@code TemporalAdjuster} however using it
1213      * as an argument typically has no effect. The offset of a {@code ZonedDateTime} is
1214      * controlled primarily by the time-zone. As such, changing the offset does not generally
1215      * make sense, because there is only one valid offset for the local date-time and zone.
1216      * If the zoned date-time is in a daylight savings overlap, then the offset is used
1217      * to switch between the two valid offsets. In all other cases, the offset is ignored.
1218      * <p>
1219      * The result of this method is obtained by invoking the
1220      * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
1221      * specified adjuster passing {@code this} as the argument.
1222      * <p>
1223      * This instance is immutable and unaffected by this method call.
1224      *
1225      * @param adjuster the adjuster to use, not null
1226      * @return a {@code ZonedDateTime} based on {@code this} with the adjustment made, not null
1227      * @throws DateTimeException if the adjustment cannot be made
1228      * @throws ArithmeticException if numeric overflow occurs
1229      */
1230     @Override
1231     public ZonedDateTime with(TemporalAdjuster adjuster) {
1232         // optimizations
1233         if (adjuster instanceof LocalDate) {
1234             return resolveLocal(LocalDateTime.of((LocalDate) adjuster, dateTime.toLocalTime()));
1235         } else if (adjuster instanceof LocalTime) {
1236             return resolveLocal(LocalDateTime.of(dateTime.toLocalDate(), (LocalTime) adjuster));
1237         } else if (adjuster instanceof LocalDateTime) {
1238             return resolveLocal((LocalDateTime) adjuster);
1239         } else if (adjuster instanceof OffsetDateTime odt) {
1240             return ofLocal(odt.toLocalDateTime(), zone, odt.getOffset());
1241         } else if (adjuster instanceof Instant instant) {
1242             return create(instant.getEpochSecond(), instant.getNano(), zone);
1243         } else if (adjuster instanceof ZoneOffset) {
1244             return resolveOffset((ZoneOffset) adjuster);
1245         }
1246         return (ZonedDateTime) adjuster.adjustInto(this);
1247     }
1248 
1249     /**
1250      * Returns a copy of this date-time with the specified field set to a new value.
1251      * <p>
1252      * This returns a {@code ZonedDateTime}, based on this one, with the value
1253      * for the specified field changed.
1254      * This can be used to change any supported field, such as the year, month or day-of-month.
1255      * If it is not possible to set the value, because the field is not supported or for
1256      * some other reason, an exception is thrown.
1257      * <p>
1258      * In some cases, changing the specified field can cause the resulting date-time to become invalid,
1259      * such as changing the month from 31st January to February would make the day-of-month invalid.
1260      * In cases like this, the field is responsible for resolving the date. Typically it will choose
1261      * the previous valid date, which would be the last valid day of February in this example.
1262      * <p>
1263      * If the field is a {@link ChronoField} then the adjustment is implemented here.
1264      * <p>
1265      * The {@code INSTANT_SECONDS} field will return a date-time with the specified instant.
1266      * The zone and nano-of-second are unchanged.
1267      * The result will have an offset derived from the new instant and original zone.
1268      * If the new instant value is outside the valid range then a {@code DateTimeException} will be thrown.
1269      * <p>
1270      * The {@code OFFSET_SECONDS} field will typically be ignored.
1271      * The offset of a {@code ZonedDateTime} is controlled primarily by the time-zone.
1272      * As such, changing the offset does not generally make sense, because there is only
1273      * one valid offset for the local date-time and zone.
1274      * If the zoned date-time is in a daylight savings overlap, then the offset is used
1275      * to switch between the two valid offsets. In all other cases, the offset is ignored.
1276      * If the new offset value is outside the valid range then a {@code DateTimeException} will be thrown.
1277      * <p>
1278      * The other {@link #isSupported(TemporalField) supported fields} will behave as per
1279      * the matching method on {@link LocalDateTime#with(TemporalField, long) LocalDateTime}.
1280      * The zone is not part of the calculation and will be unchanged.
1281      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1282      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1283      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1284      * <p>
1285      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
1286      * <p>
1287      * If the field is not a {@code ChronoField}, then the result of this method
1288      * is obtained by invoking {@code TemporalField.adjustInto(Temporal, long)}
1289      * passing {@code this} as the argument. In this case, the field determines
1290      * whether and how to adjust the instant.
1291      * <p>
1292      * This instance is immutable and unaffected by this method call.
1293      *
1294      * @param field  the field to set in the result, not null
1295      * @param newValue  the new value of the field in the result
1296      * @return a {@code ZonedDateTime} based on {@code this} with the specified field set, not null
1297      * @throws DateTimeException if the field cannot be set
1298      * @throws UnsupportedTemporalTypeException if the field is not supported
1299      * @throws ArithmeticException if numeric overflow occurs
1300      */
1301     @Override
1302     public ZonedDateTime with(TemporalField field, long newValue) {
1303         if (field instanceof ChronoField chronoField) {
1304             return switch (chronoField) {
1305                 case INSTANT_SECONDS -> create(newValue, getNano(), zone);
1306                 case OFFSET_SECONDS -> {
1307                     ZoneOffset offset = ZoneOffset.ofTotalSeconds(chronoField.checkValidIntValue(newValue));
1308                     yield resolveOffset(offset);
1309                 }
1310                 default -> resolveLocal(dateTime.with(field, newValue));
1311             };
1312         }
1313         return field.adjustInto(this, newValue);
1314     }
1315 
1316     //-----------------------------------------------------------------------
1317     /**
1318      * Returns a copy of this {@code ZonedDateTime} with the year altered.
1319      * <p>
1320      * This operates on the local time-line,
1321      * {@link LocalDateTime#withYear(int) changing the year} of the local date-time.
1322      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1323      * to obtain the offset.
1324      * <p>
1325      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1326      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1327      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1328      * <p>
1329      * This instance is immutable and unaffected by this method call.
1330      *
1331      * @param year  the year to set in the result, from MIN_YEAR to MAX_YEAR
1332      * @return a {@code ZonedDateTime} based on this date-time with the requested year, not null
1333      * @throws DateTimeException if the year value is invalid
1334      */
1335     public ZonedDateTime withYear(int year) {
1336         return resolveLocal(dateTime.withYear(year));
1337     }
1338 
1339     /**
1340      * Returns a copy of this {@code ZonedDateTime} with the month-of-year altered.
1341      * <p>
1342      * This operates on the local time-line,
1343      * {@link LocalDateTime#withMonth(int) changing the month} of the local date-time.
1344      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1345      * to obtain the offset.
1346      * <p>
1347      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1348      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1349      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1350      * <p>
1351      * This instance is immutable and unaffected by this method call.
1352      *
1353      * @param month  the month-of-year to set in the result, from 1 (January) to 12 (December)
1354      * @return a {@code ZonedDateTime} based on this date-time with the requested month, not null
1355      * @throws DateTimeException if the month-of-year value is invalid
1356      */
1357     public ZonedDateTime withMonth(int month) {
1358         return resolveLocal(dateTime.withMonth(month));
1359     }
1360 
1361     /**
1362      * Returns a copy of this {@code ZonedDateTime} with the day-of-month altered.
1363      * <p>
1364      * This operates on the local time-line,
1365      * {@link LocalDateTime#withDayOfMonth(int) changing the day-of-month} of the local date-time.
1366      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1367      * to obtain the offset.
1368      * <p>
1369      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1370      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1371      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1372      * <p>
1373      * This instance is immutable and unaffected by this method call.
1374      *
1375      * @param dayOfMonth  the day-of-month to set in the result, from 1 to 28-31
1376      * @return a {@code ZonedDateTime} based on this date-time with the requested day, not null
1377      * @throws DateTimeException if the day-of-month value is invalid,
1378      *  or if the day-of-month is invalid for the month-year
1379      */
1380     public ZonedDateTime withDayOfMonth(int dayOfMonth) {
1381         return resolveLocal(dateTime.withDayOfMonth(dayOfMonth));
1382     }
1383 
1384     /**
1385      * Returns a copy of this {@code ZonedDateTime} with the day-of-year altered.
1386      * <p>
1387      * This operates on the local time-line,
1388      * {@link LocalDateTime#withDayOfYear(int) changing the day-of-year} of the local date-time.
1389      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1390      * to obtain the offset.
1391      * <p>
1392      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1393      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1394      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1395      * <p>
1396      * This instance is immutable and unaffected by this method call.
1397      *
1398      * @param dayOfYear  the day-of-year to set in the result, from 1 to 365-366
1399      * @return a {@code ZonedDateTime} based on this date with the requested day, not null
1400      * @throws DateTimeException if the day-of-year value is invalid,
1401      *  or if the day-of-year is invalid for the year
1402      */
1403     public ZonedDateTime withDayOfYear(int dayOfYear) {
1404         return resolveLocal(dateTime.withDayOfYear(dayOfYear));
1405     }
1406 
1407     //-----------------------------------------------------------------------
1408     /**
1409      * Returns a copy of this {@code ZonedDateTime} with the hour-of-day altered.
1410      * <p>
1411      * This operates on the local time-line,
1412      * {@linkplain LocalDateTime#withHour(int) changing the time} of the local date-time.
1413      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1414      * to obtain the offset.
1415      * <p>
1416      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1417      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1418      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1419      * <p>
1420      * This instance is immutable and unaffected by this method call.
1421      *
1422      * @param hour  the hour-of-day to set in the result, from 0 to 23
1423      * @return a {@code ZonedDateTime} based on this date-time with the requested hour, not null
1424      * @throws DateTimeException if the hour value is invalid
1425      */
1426     public ZonedDateTime withHour(int hour) {
1427         return resolveLocal(dateTime.withHour(hour));
1428     }
1429 
1430     /**
1431      * Returns a copy of this {@code ZonedDateTime} with the minute-of-hour altered.
1432      * <p>
1433      * This operates on the local time-line,
1434      * {@linkplain LocalDateTime#withMinute(int) changing the time} of the local date-time.
1435      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1436      * to obtain the offset.
1437      * <p>
1438      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1439      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1440      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1441      * <p>
1442      * This instance is immutable and unaffected by this method call.
1443      *
1444      * @param minute  the minute-of-hour to set in the result, from 0 to 59
1445      * @return a {@code ZonedDateTime} based on this date-time with the requested minute, not null
1446      * @throws DateTimeException if the minute value is invalid
1447      */
1448     public ZonedDateTime withMinute(int minute) {
1449         return resolveLocal(dateTime.withMinute(minute));
1450     }
1451 
1452     /**
1453      * Returns a copy of this {@code ZonedDateTime} with the second-of-minute altered.
1454      * <p>
1455      * This operates on the local time-line,
1456      * {@linkplain LocalDateTime#withSecond(int) changing the time} of the local date-time.
1457      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1458      * to obtain the offset.
1459      * <p>
1460      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1461      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1462      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1463      * <p>
1464      * This instance is immutable and unaffected by this method call.
1465      *
1466      * @param second  the second-of-minute to set in the result, from 0 to 59
1467      * @return a {@code ZonedDateTime} based on this date-time with the requested second, not null
1468      * @throws DateTimeException if the second value is invalid
1469      */
1470     public ZonedDateTime withSecond(int second) {
1471         return resolveLocal(dateTime.withSecond(second));
1472     }
1473 
1474     /**
1475      * Returns a copy of this {@code ZonedDateTime} with the nano-of-second altered.
1476      * <p>
1477      * This operates on the local time-line,
1478      * {@linkplain LocalDateTime#withNano(int) changing the time} of the local date-time.
1479      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1480      * to obtain the offset.
1481      * <p>
1482      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1483      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1484      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1485      * <p>
1486      * This instance is immutable and unaffected by this method call.
1487      *
1488      * @param nanoOfSecond  the nano-of-second to set in the result, from 0 to 999,999,999
1489      * @return a {@code ZonedDateTime} based on this date-time with the requested nanosecond, not null
1490      * @throws DateTimeException if the nano value is invalid
1491      */
1492     public ZonedDateTime withNano(int nanoOfSecond) {
1493         return resolveLocal(dateTime.withNano(nanoOfSecond));
1494     }
1495 
1496     //-----------------------------------------------------------------------
1497     /**
1498      * Returns a copy of this {@code ZonedDateTime} with the time truncated.
1499      * <p>
1500      * Truncation returns a copy of the original date-time with fields
1501      * smaller than the specified unit set to zero.
1502      * For example, truncating with the {@link ChronoUnit#MINUTES minutes} unit
1503      * will set the second-of-minute and nano-of-second field to zero.
1504      * <p>
1505      * The unit must have a {@linkplain TemporalUnit#getDuration() duration}
1506      * that divides into the length of a standard day without remainder.
1507      * This includes all supplied time units on {@link ChronoUnit} and
1508      * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception.
1509      * <p>
1510      * This operates on the local time-line,
1511      * {@link LocalDateTime#truncatedTo(TemporalUnit) truncating}
1512      * the underlying local date-time. This is then converted back to a
1513      * {@code ZonedDateTime}, using the zone ID to obtain the offset.
1514      * <p>
1515      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1516      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1517      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1518      * <p>
1519      * This instance is immutable and unaffected by this method call.
1520      *
1521      * @param unit  the unit to truncate to, not null
1522      * @return a {@code ZonedDateTime} based on this date-time with the time truncated, not null
1523      * @throws DateTimeException if unable to truncate
1524      * @throws UnsupportedTemporalTypeException if the unit is not supported
1525      */
1526     public ZonedDateTime truncatedTo(TemporalUnit unit) {
1527         return resolveLocal(dateTime.truncatedTo(unit));
1528     }
1529 
1530     //-----------------------------------------------------------------------
1531     /**
1532      * Returns a copy of this date-time with the specified amount added.
1533      * <p>
1534      * This returns a {@code ZonedDateTime}, based on this one, with the specified amount added.
1535      * The amount is typically {@link Period} or {@link Duration} but may be
1536      * any other type implementing the {@link TemporalAmount} interface.
1537      * <p>
1538      * The calculation is delegated to the amount object by calling
1539      * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
1540      * to implement the addition in any way it wishes, however it typically
1541      * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
1542      * of the amount implementation to determine if it can be successfully added.
1543      * <p>
1544      * This instance is immutable and unaffected by this method call.
1545      *
1546      * @param amountToAdd  the amount to add, not null
1547      * @return a {@code ZonedDateTime} based on this date-time with the addition made, not null
1548      * @throws DateTimeException if the addition cannot be made
1549      * @throws ArithmeticException if numeric overflow occurs
1550      */
1551     @Override
1552     public ZonedDateTime plus(TemporalAmount amountToAdd) {
1553         if (amountToAdd instanceof Period periodToAdd) {
1554             return resolveLocal(dateTime.plus(periodToAdd));
1555         }
1556         Objects.requireNonNull(amountToAdd, "amountToAdd");
1557         return (ZonedDateTime) amountToAdd.addTo(this);
1558     }
1559 
1560     /**
1561      * Returns a copy of this date-time with the specified amount added.
1562      * <p>
1563      * This returns a {@code ZonedDateTime}, based on this one, with the amount
1564      * in terms of the unit added. If it is not possible to add the amount, because the
1565      * unit is not supported or for some other reason, an exception is thrown.
1566      * <p>
1567      * If the field is a {@link ChronoUnit} then the addition is implemented here.
1568      * The zone is not part of the calculation and will be unchanged in the result.
1569      * The calculation for date and time units differ.
1570      * <p>
1571      * Date units operate on the local time-line.
1572      * The period is first added to the local date-time, then converted back
1573      * to a zoned date-time using the zone ID.
1574      * The conversion uses {@link #ofLocal(LocalDateTime, ZoneId, ZoneOffset)}
1575      * with the offset before the addition.
1576      * <p>
1577      * Time units operate on the instant time-line.
1578      * The period is first added to the local date-time, then converted back to
1579      * a zoned date-time using the zone ID.
1580      * The conversion uses {@link #ofInstant(LocalDateTime, ZoneOffset, ZoneId)}
1581      * with the offset before the addition.
1582      * <p>
1583      * If the field is not a {@code ChronoUnit}, then the result of this method
1584      * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
1585      * passing {@code this} as the argument. In this case, the unit determines
1586      * whether and how to perform the addition.
1587      * <p>
1588      * This instance is immutable and unaffected by this method call.
1589      *
1590      * @param amountToAdd  the amount of the unit to add to the result, may be negative
1591      * @param unit  the unit of the amount to add, not null
1592      * @return a {@code ZonedDateTime} based on this date-time with the specified amount added, not null
1593      * @throws DateTimeException if the addition cannot be made
1594      * @throws UnsupportedTemporalTypeException if the unit is not supported
1595      * @throws ArithmeticException if numeric overflow occurs
1596      */
1597     @Override
1598     public ZonedDateTime plus(long amountToAdd, TemporalUnit unit) {
1599         if (unit instanceof ChronoUnit) {
1600             if (unit.isDateBased()) {
1601                 return resolveLocal(dateTime.plus(amountToAdd, unit));
1602             } else {
1603                 return resolveInstant(dateTime.plus(amountToAdd, unit));
1604             }
1605         }
1606         return unit.addTo(this, amountToAdd);
1607     }
1608 
1609     //-----------------------------------------------------------------------
1610     /**
1611      * Returns a copy of this {@code ZonedDateTime} with the specified number of years added.
1612      * <p>
1613      * This operates on the local time-line,
1614      * {@link LocalDateTime#plusYears(long) adding years} to the local date-time.
1615      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1616      * to obtain the offset.
1617      * <p>
1618      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1619      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1620      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1621      * <p>
1622      * This instance is immutable and unaffected by this method call.
1623      *
1624      * @param years  the years to add, may be negative
1625      * @return a {@code ZonedDateTime} based on this date-time with the years added, not null
1626      * @throws DateTimeException if the result exceeds the supported date range
1627      */
1628     public ZonedDateTime plusYears(long years) {
1629         return resolveLocal(dateTime.plusYears(years));
1630     }
1631 
1632     /**
1633      * Returns a copy of this {@code ZonedDateTime} with the specified number of months added.
1634      * <p>
1635      * This operates on the local time-line,
1636      * {@link LocalDateTime#plusMonths(long) adding months} to the local date-time.
1637      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1638      * to obtain the offset.
1639      * <p>
1640      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1641      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1642      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1643      * <p>
1644      * This instance is immutable and unaffected by this method call.
1645      *
1646      * @param months  the months to add, may be negative
1647      * @return a {@code ZonedDateTime} based on this date-time with the months added, not null
1648      * @throws DateTimeException if the result exceeds the supported date range
1649      */
1650     public ZonedDateTime plusMonths(long months) {
1651         return resolveLocal(dateTime.plusMonths(months));
1652     }
1653 
1654     /**
1655      * Returns a copy of this {@code ZonedDateTime} with the specified number of weeks added.
1656      * <p>
1657      * This operates on the local time-line,
1658      * {@link LocalDateTime#plusWeeks(long) adding weeks} to the local date-time.
1659      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1660      * to obtain the offset.
1661      * <p>
1662      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1663      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1664      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1665      * <p>
1666      * This instance is immutable and unaffected by this method call.
1667      *
1668      * @param weeks  the weeks to add, may be negative
1669      * @return a {@code ZonedDateTime} based on this date-time with the weeks added, not null
1670      * @throws DateTimeException if the result exceeds the supported date range
1671      */
1672     public ZonedDateTime plusWeeks(long weeks) {
1673         return resolveLocal(dateTime.plusWeeks(weeks));
1674     }
1675 
1676     /**
1677      * Returns a copy of this {@code ZonedDateTime} with the specified number of days added.
1678      * <p>
1679      * This operates on the local time-line,
1680      * {@link LocalDateTime#plusDays(long) adding days} to the local date-time.
1681      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1682      * to obtain the offset.
1683      * <p>
1684      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1685      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1686      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1687      * <p>
1688      * This instance is immutable and unaffected by this method call.
1689      *
1690      * @param days  the days to add, may be negative
1691      * @return a {@code ZonedDateTime} based on this date-time with the days added, not null
1692      * @throws DateTimeException if the result exceeds the supported date range
1693      */
1694     public ZonedDateTime plusDays(long days) {
1695         return resolveLocal(dateTime.plusDays(days));
1696     }
1697 
1698     //-----------------------------------------------------------------------
1699     /**
1700      * Returns a copy of this {@code ZonedDateTime} with the specified number of hours added.
1701      * <p>
1702      * This operates on the instant time-line, such that adding one hour will
1703      * always be a duration of one hour later.
1704      * This may cause the local date-time to change by an amount other than one hour.
1705      * Note that this is a different approach to that used by days, months and years,
1706      * thus adding one day is not the same as adding 24 hours.
1707      * <p>
1708      * For example, consider a time-zone, such as 'Europe/Paris', where the
1709      * Autumn DST cutover means that the local times 02:00 to 02:59 occur twice
1710      * changing from offset +02:00 in summer to +01:00 in winter.
1711      * <ul>
1712      * <li>Adding one hour to 01:30+02:00 will result in 02:30+02:00
1713      *     (both in summer time)
1714      * <li>Adding one hour to 02:30+02:00 will result in 02:30+01:00
1715      *     (moving from summer to winter time)
1716      * <li>Adding one hour to 02:30+01:00 will result in 03:30+01:00
1717      *     (both in winter time)
1718      * <li>Adding three hours to 01:30+02:00 will result in 03:30+01:00
1719      *     (moving from summer to winter time)
1720      * </ul>
1721      * <p>
1722      * This instance is immutable and unaffected by this method call.
1723      *
1724      * @param hours  the hours to add, may be negative
1725      * @return a {@code ZonedDateTime} based on this date-time with the hours added, not null
1726      * @throws DateTimeException if the result exceeds the supported date range
1727      */
1728     public ZonedDateTime plusHours(long hours) {
1729         return resolveInstant(dateTime.plusHours(hours));
1730     }
1731 
1732     /**
1733      * Returns a copy of this {@code ZonedDateTime} with the specified number of minutes added.
1734      * <p>
1735      * This operates on the instant time-line, such that adding one minute will
1736      * always be a duration of one minute later.
1737      * This may cause the local date-time to change by an amount other than one minute.
1738      * Note that this is a different approach to that used by days, months and years.
1739      * <p>
1740      * This instance is immutable and unaffected by this method call.
1741      *
1742      * @param minutes  the minutes to add, may be negative
1743      * @return a {@code ZonedDateTime} based on this date-time with the minutes added, not null
1744      * @throws DateTimeException if the result exceeds the supported date range
1745      */
1746     public ZonedDateTime plusMinutes(long minutes) {
1747         return resolveInstant(dateTime.plusMinutes(minutes));
1748     }
1749 
1750     /**
1751      * Returns a copy of this {@code ZonedDateTime} with the specified number of seconds added.
1752      * <p>
1753      * This operates on the instant time-line, such that adding one second will
1754      * always be a duration of one second later.
1755      * This may cause the local date-time to change by an amount other than one second.
1756      * Note that this is a different approach to that used by days, months and years.
1757      * <p>
1758      * This instance is immutable and unaffected by this method call.
1759      *
1760      * @param seconds  the seconds to add, may be negative
1761      * @return a {@code ZonedDateTime} based on this date-time with the seconds added, not null
1762      * @throws DateTimeException if the result exceeds the supported date range
1763      */
1764     public ZonedDateTime plusSeconds(long seconds) {
1765         return resolveInstant(dateTime.plusSeconds(seconds));
1766     }
1767 
1768     /**
1769      * Returns a copy of this {@code ZonedDateTime} with the specified number of nanoseconds added.
1770      * <p>
1771      * This operates on the instant time-line, such that adding one nano will
1772      * always be a duration of one nano later.
1773      * This may cause the local date-time to change by an amount other than one nano.
1774      * Note that this is a different approach to that used by days, months and years.
1775      * <p>
1776      * This instance is immutable and unaffected by this method call.
1777      *
1778      * @param nanos  the nanos to add, may be negative
1779      * @return a {@code ZonedDateTime} based on this date-time with the nanoseconds added, not null
1780      * @throws DateTimeException if the result exceeds the supported date range
1781      */
1782     public ZonedDateTime plusNanos(long nanos) {
1783         return resolveInstant(dateTime.plusNanos(nanos));
1784     }
1785 
1786     //-----------------------------------------------------------------------
1787     /**
1788      * Returns a copy of this date-time with the specified amount subtracted.
1789      * <p>
1790      * This returns a {@code ZonedDateTime}, based on this one, with the specified amount subtracted.
1791      * The amount is typically {@link Period} or {@link Duration} but may be
1792      * any other type implementing the {@link TemporalAmount} interface.
1793      * <p>
1794      * The calculation is delegated to the amount object by calling
1795      * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free
1796      * to implement the subtraction in any way it wishes, however it typically
1797      * calls back to {@link #minus(long, TemporalUnit)}. Consult the documentation
1798      * of the amount implementation to determine if it can be successfully subtracted.
1799      * <p>
1800      * This instance is immutable and unaffected by this method call.
1801      *
1802      * @param amountToSubtract  the amount to subtract, not null
1803      * @return a {@code ZonedDateTime} based on this date-time with the subtraction made, not null
1804      * @throws DateTimeException if the subtraction cannot be made
1805      * @throws ArithmeticException if numeric overflow occurs
1806      */
1807     @Override
1808     public ZonedDateTime minus(TemporalAmount amountToSubtract) {
1809         if (amountToSubtract instanceof Period periodToSubtract) {
1810             return resolveLocal(dateTime.minus(periodToSubtract));
1811         }
1812         Objects.requireNonNull(amountToSubtract, "amountToSubtract");
1813         return (ZonedDateTime) amountToSubtract.subtractFrom(this);
1814     }
1815 
1816     /**
1817      * Returns a copy of this date-time with the specified amount subtracted.
1818      * <p>
1819      * This returns a {@code ZonedDateTime}, based on this one, with the amount
1820      * in terms of the unit subtracted. If it is not possible to subtract the amount,
1821      * because the unit is not supported or for some other reason, an exception is thrown.
1822      * <p>
1823      * The calculation for date and time units differ.
1824      * <p>
1825      * Date units operate on the local time-line.
1826      * The period is first subtracted from the local date-time, then converted back
1827      * to a zoned date-time using the zone ID.
1828      * The conversion uses {@link #ofLocal(LocalDateTime, ZoneId, ZoneOffset)}
1829      * with the offset before the subtraction.
1830      * <p>
1831      * Time units operate on the instant time-line.
1832      * The period is first subtracted from the local date-time, then converted back to
1833      * a zoned date-time using the zone ID.
1834      * The conversion uses {@link #ofInstant(LocalDateTime, ZoneOffset, ZoneId)}
1835      * with the offset before the subtraction.
1836      * <p>
1837      * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
1838      * See that method for a full description of how addition, and thus subtraction, works.
1839      * <p>
1840      * This instance is immutable and unaffected by this method call.
1841      *
1842      * @param amountToSubtract  the amount of the unit to subtract from the result, may be negative
1843      * @param unit  the unit of the amount to subtract, not null
1844      * @return a {@code ZonedDateTime} based on this date-time with the specified amount subtracted, not null
1845      * @throws DateTimeException if the subtraction cannot be made
1846      * @throws UnsupportedTemporalTypeException if the unit is not supported
1847      * @throws ArithmeticException if numeric overflow occurs
1848      */
1849     @Override
1850     public ZonedDateTime minus(long amountToSubtract, TemporalUnit unit) {
1851         return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
1852     }
1853 
1854     //-----------------------------------------------------------------------
1855     /**
1856      * Returns a copy of this {@code ZonedDateTime} with the specified number of years subtracted.
1857      * <p>
1858      * This operates on the local time-line,
1859      * {@link LocalDateTime#minusYears(long) subtracting years} to the local date-time.
1860      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1861      * to obtain the offset.
1862      * <p>
1863      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1864      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1865      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1866      * <p>
1867      * This instance is immutable and unaffected by this method call.
1868      *
1869      * @param years  the years to subtract, may be negative
1870      * @return a {@code ZonedDateTime} based on this date-time with the years subtracted, not null
1871      * @throws DateTimeException if the result exceeds the supported date range
1872      */
1873     public ZonedDateTime minusYears(long years) {
1874         return (years == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-years));
1875     }
1876 
1877     /**
1878      * Returns a copy of this {@code ZonedDateTime} with the specified number of months subtracted.
1879      * <p>
1880      * This operates on the local time-line,
1881      * {@link LocalDateTime#minusMonths(long) subtracting months} to the local date-time.
1882      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1883      * to obtain the offset.
1884      * <p>
1885      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1886      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1887      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1888      * <p>
1889      * This instance is immutable and unaffected by this method call.
1890      *
1891      * @param months  the months to subtract, may be negative
1892      * @return a {@code ZonedDateTime} based on this date-time with the months subtracted, not null
1893      * @throws DateTimeException if the result exceeds the supported date range
1894      */
1895     public ZonedDateTime minusMonths(long months) {
1896         return (months == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1) : plusMonths(-months));
1897     }
1898 
1899     /**
1900      * Returns a copy of this {@code ZonedDateTime} with the specified number of weeks subtracted.
1901      * <p>
1902      * This operates on the local time-line,
1903      * {@link LocalDateTime#minusWeeks(long) subtracting weeks} to the local date-time.
1904      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1905      * to obtain the offset.
1906      * <p>
1907      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1908      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1909      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1910      * <p>
1911      * This instance is immutable and unaffected by this method call.
1912      *
1913      * @param weeks  the weeks to subtract, may be negative
1914      * @return a {@code ZonedDateTime} based on this date-time with the weeks subtracted, not null
1915      * @throws DateTimeException if the result exceeds the supported date range
1916      */
1917     public ZonedDateTime minusWeeks(long weeks) {
1918         return (weeks == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1) : plusWeeks(-weeks));
1919     }
1920 
1921     /**
1922      * Returns a copy of this {@code ZonedDateTime} with the specified number of days subtracted.
1923      * <p>
1924      * This operates on the local time-line,
1925      * {@link LocalDateTime#minusDays(long) subtracting days} to the local date-time.
1926      * This is then converted back to a {@code ZonedDateTime}, using the zone ID
1927      * to obtain the offset.
1928      * <p>
1929      * When converting back to {@code ZonedDateTime}, if the local date-time is in an overlap,
1930      * then the offset will be retained if possible, otherwise the earlier offset will be used.
1931      * If in a gap, the local date-time will be adjusted forward by the length of the gap.
1932      * <p>
1933      * This instance is immutable and unaffected by this method call.
1934      *
1935      * @param days  the days to subtract, may be negative
1936      * @return a {@code ZonedDateTime} based on this date-time with the days subtracted, not null
1937      * @throws DateTimeException if the result exceeds the supported date range
1938      */
1939     public ZonedDateTime minusDays(long days) {
1940         return (days == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-days));
1941     }
1942 
1943     //-----------------------------------------------------------------------
1944     /**
1945      * Returns a copy of this {@code ZonedDateTime} with the specified number of hours subtracted.
1946      * <p>
1947      * This operates on the instant time-line, such that subtracting one hour will
1948      * always be a duration of one hour earlier.
1949      * This may cause the local date-time to change by an amount other than one hour.
1950      * Note that this is a different approach to that used by days, months and years,
1951      * thus subtracting one day is not the same as adding 24 hours.
1952      * <p>
1953      * For example, consider a time-zone, such as 'Europe/Paris', where the
1954      * Autumn DST cutover means that the local times 02:00 to 02:59 occur twice
1955      * changing from offset +02:00 in summer to +01:00 in winter.
1956      * <ul>
1957      * <li>Subtracting one hour from 03:30+01:00 will result in 02:30+01:00
1958      *     (both in winter time)
1959      * <li>Subtracting one hour from 02:30+01:00 will result in 02:30+02:00
1960      *     (moving from winter to summer time)
1961      * <li>Subtracting one hour from 02:30+02:00 will result in 01:30+02:00
1962      *     (both in summer time)
1963      * <li>Subtracting three hours from 03:30+01:00 will result in 01:30+02:00
1964      *     (moving from winter to summer time)
1965      * </ul>
1966      * <p>
1967      * This instance is immutable and unaffected by this method call.
1968      *
1969      * @param hours  the hours to subtract, may be negative
1970      * @return a {@code ZonedDateTime} based on this date-time with the hours subtracted, not null
1971      * @throws DateTimeException if the result exceeds the supported date range
1972      */
1973     public ZonedDateTime minusHours(long hours) {
1974         return (hours == Long.MIN_VALUE ? plusHours(Long.MAX_VALUE).plusHours(1) : plusHours(-hours));
1975     }
1976 
1977     /**
1978      * Returns a copy of this {@code ZonedDateTime} with the specified number of minutes subtracted.
1979      * <p>
1980      * This operates on the instant time-line, such that subtracting one minute will
1981      * always be a duration of one minute earlier.
1982      * This may cause the local date-time to change by an amount other than one minute.
1983      * Note that this is a different approach to that used by days, months and years.
1984      * <p>
1985      * This instance is immutable and unaffected by this method call.
1986      *
1987      * @param minutes  the minutes to subtract, may be negative
1988      * @return a {@code ZonedDateTime} based on this date-time with the minutes subtracted, not null
1989      * @throws DateTimeException if the result exceeds the supported date range
1990      */
1991     public ZonedDateTime minusMinutes(long minutes) {
1992         return (minutes == Long.MIN_VALUE ? plusMinutes(Long.MAX_VALUE).plusMinutes(1) : plusMinutes(-minutes));
1993     }
1994 
1995     /**
1996      * Returns a copy of this {@code ZonedDateTime} with the specified number of seconds subtracted.
1997      * <p>
1998      * This operates on the instant time-line, such that subtracting one second will
1999      * always be a duration of one second earlier.
2000      * This may cause the local date-time to change by an amount other than one second.
2001      * Note that this is a different approach to that used by days, months and years.
2002      * <p>
2003      * This instance is immutable and unaffected by this method call.
2004      *
2005      * @param seconds  the seconds to subtract, may be negative
2006      * @return a {@code ZonedDateTime} based on this date-time with the seconds subtracted, not null
2007      * @throws DateTimeException if the result exceeds the supported date range
2008      */
2009     public ZonedDateTime minusSeconds(long seconds) {
2010         return (seconds == Long.MIN_VALUE ? plusSeconds(Long.MAX_VALUE).plusSeconds(1) : plusSeconds(-seconds));
2011     }
2012 
2013     /**
2014      * Returns a copy of this {@code ZonedDateTime} with the specified number of nanoseconds subtracted.
2015      * <p>
2016      * This operates on the instant time-line, such that subtracting one nano will
2017      * always be a duration of one nano earlier.
2018      * This may cause the local date-time to change by an amount other than one nano.
2019      * Note that this is a different approach to that used by days, months and years.
2020      * <p>
2021      * This instance is immutable and unaffected by this method call.
2022      *
2023      * @param nanos  the nanos to subtract, may be negative
2024      * @return a {@code ZonedDateTime} based on this date-time with the nanoseconds subtracted, not null
2025      * @throws DateTimeException if the result exceeds the supported date range
2026      */
2027     public ZonedDateTime minusNanos(long nanos) {
2028         return (nanos == Long.MIN_VALUE ? plusNanos(Long.MAX_VALUE).plusNanos(1) : plusNanos(-nanos));
2029     }
2030 
2031     //-----------------------------------------------------------------------
2032     /**
2033      * Queries this date-time using the specified query.
2034      * <p>
2035      * This queries this date-time using the specified query strategy object.
2036      * The {@code TemporalQuery} object defines the logic to be used to
2037      * obtain the result. Read the documentation of the query to understand
2038      * what the result of this method will be.
2039      * <p>
2040      * The result of this method is obtained by invoking the
2041      * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
2042      * specified query passing {@code this} as the argument.
2043      *
2044      * @param <R> the type of the result
2045      * @param query  the query to invoke, not null
2046      * @return the query result, null may be returned (defined by the query)
2047      * @throws DateTimeException if unable to query (defined by the query)
2048      * @throws ArithmeticException if numeric overflow occurs (defined by the query)
2049      */
2050     @SuppressWarnings("unchecked")
2051     @Override  // override for Javadoc
2052     public <R> R query(TemporalQuery<R> query) {
2053         if (query == TemporalQueries.localDate()) {
2054             return (R) toLocalDate();
2055         }
2056         return ChronoZonedDateTime.super.query(query);
2057     }
2058 
2059     /**
2060      * Calculates the amount of time until another date-time in terms of the specified unit.
2061      * <p>
2062      * This calculates the amount of time between two {@code ZonedDateTime}
2063      * objects in terms of a single {@code TemporalUnit}.
2064      * The start and end points are {@code this} and the specified date-time.
2065      * The result will be negative if the end is before the start.
2066      * For example, the amount in days between two date-times can be calculated
2067      * using {@code startDateTime.until(endDateTime, DAYS)}.
2068      * <p>
2069      * The {@code Temporal} passed to this method is converted to a
2070      * {@code ZonedDateTime} using {@link #from(TemporalAccessor)}.
2071      * If the time-zone differs between the two zoned date-times, the specified
2072      * end date-time is normalized to have the same zone as this date-time.
2073      * <p>
2074      * The calculation returns a whole number, representing the number of
2075      * complete units between the two date-times.
2076      * For example, the amount in months between 2012-06-15T00:00Z and 2012-08-14T23:59Z
2077      * will only be one month as it is one minute short of two months.
2078      * <p>
2079      * There are two equivalent ways of using this method.
2080      * The first is to invoke this method.
2081      * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
2082      * <pre>
2083      *   // these two lines are equivalent
2084      *   amount = start.until(end, MONTHS);
2085      *   amount = MONTHS.between(start, end);
2086      * </pre>
2087      * The choice should be made based on which makes the code more readable.
2088      * <p>
2089      * The calculation is implemented in this method for {@link ChronoUnit}.
2090      * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
2091      * {@code MINUTES}, {@code HOURS} and {@code HALF_DAYS}, {@code DAYS},
2092      * {@code WEEKS}, {@code MONTHS}, {@code YEARS}, {@code DECADES},
2093      * {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS} are supported.
2094      * Other {@code ChronoUnit} values will throw an exception.
2095      * <p>
2096      * The calculation for date and time units differ.
2097      * <p>
2098      * Date units operate on the local time-line, using the local date-time.
2099      * For example, the period from noon on day 1 to noon the following day
2100      * in days will always be counted as exactly one day, irrespective of whether
2101      * there was a daylight savings change or not.
2102      * <p>
2103      * Time units operate on the instant time-line.
2104      * The calculation effectively converts both zoned date-times to instants
2105      * and then calculates the period between the instants.
2106      * For example, the period from noon on day 1 to noon the following day
2107      * in hours may be 23, 24 or 25 hours (or some other amount) depending on
2108      * whether there was a daylight savings change or not.
2109      * <p>
2110      * If the unit is not a {@code ChronoUnit}, then the result of this method
2111      * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
2112      * passing {@code this} as the first argument and the converted input temporal
2113      * as the second argument.
2114      * <p>
2115      * This instance is immutable and unaffected by this method call.
2116      *
2117      * @param endExclusive  the end date, exclusive, which is converted to a {@code ZonedDateTime}, not null
2118      * @param unit  the unit to measure the amount in, not null
2119      * @return the amount of time between this date-time and the end date-time
2120      * @throws DateTimeException if the amount cannot be calculated, or the end
2121      *  temporal cannot be converted to a {@code ZonedDateTime}
2122      * @throws UnsupportedTemporalTypeException if the unit is not supported
2123      * @throws ArithmeticException if numeric overflow occurs
2124      */
2125     @Override
2126     public long until(Temporal endExclusive, TemporalUnit unit) {
2127         ZonedDateTime end = ZonedDateTime.from(endExclusive);
2128         if (unit instanceof ChronoUnit) {
2129             ZonedDateTime start = this;
2130             try {
2131                 end = end.withZoneSameInstant(zone);
2132             } catch (DateTimeException ex) {
2133                 // end may be out of valid range. Adjust to end's zone.
2134                 start = withZoneSameInstant(end.zone);
2135             }
2136             if (unit.isDateBased()) {
2137                 return start.dateTime.until(end.dateTime, unit);
2138             } else {
2139                 return start.toOffsetDateTime().until(end.toOffsetDateTime(), unit);
2140             }
2141         }
2142         return unit.between(this, end);
2143     }
2144 
2145     /**
2146      * Formats this date-time using the specified formatter.
2147      * <p>
2148      * This date-time will be passed to the formatter to produce a string.
2149      *
2150      * @param formatter  the formatter to use, not null
2151      * @return the formatted date-time string, not null
2152      * @throws DateTimeException if an error occurs during printing
2153      */
2154     @Override  // override for Javadoc and performance
2155     public String format(DateTimeFormatter formatter) {
2156         Objects.requireNonNull(formatter, "formatter");
2157         return formatter.format(this);
2158     }
2159 
2160     //-----------------------------------------------------------------------
2161     /**
2162      * Converts this date-time to an {@code OffsetDateTime}.
2163      * <p>
2164      * This creates an offset date-time using the local date-time and offset.
2165      * The zone ID is ignored.
2166      *
2167      * @return an offset date-time representing the same local date-time and offset, not null
2168      */
2169     public OffsetDateTime toOffsetDateTime() {
2170         return OffsetDateTime.of(dateTime, offset);
2171     }
2172 
2173     //-----------------------------------------------------------------------
2174     /**
2175      * Checks if this date-time is equal to another date-time.
2176      * <p>
2177      * The comparison is based on the offset date-time and the zone.
2178      * Only objects of type {@code ZonedDateTime} are compared, other types return false.
2179      *
2180      * @param obj  the object to check, null returns false
2181      * @return true if this is equal to the other date-time
2182      */
2183     @Override
2184     public boolean equals(Object obj) {
2185         if (this == obj) {
2186             return true;
2187         }
2188         return obj instanceof ZonedDateTime other
2189                 && dateTime.equals(other.dateTime)
2190                 && offset.equals(other.offset)
2191                 && zone.equals(other.zone);
2192     }
2193 
2194     /**
2195      * A hash code for this date-time.
2196      *
2197      * @return a suitable hash code
2198      */
2199     @Override
2200     public int hashCode() {
2201         return dateTime.hashCode() ^ offset.hashCode() ^ Integer.rotateLeft(zone.hashCode(), 3);
2202     }
2203 
2204     //-----------------------------------------------------------------------
2205     /**
2206      * Outputs this date-time as a {@code String}, such as
2207      * {@code 2007-12-03T10:15:30+01:00[Europe/Paris]}.
2208      * <p>
2209      * The format consists of the {@code LocalDateTime} followed by the {@code ZoneOffset}.
2210      * If the {@code ZoneId} is not the same as the offset, then the ID is output.
2211      * The output is compatible with ISO-8601 if the offset and ID are the same,
2212      * and the seconds in the offset are zero.
2213      *
2214      * @return a string representation of this date-time, not null
2215      */
2216     @Override  // override for Javadoc
2217     public String toString() {
2218         var offsetStr = offset.toString();
2219         var zoneStr = (String) null;
2220         int length = 29 + offsetStr.length();
2221         if (offset != zone) {
2222             zoneStr = zone.toString();
2223             length += zoneStr.length() + 2;
2224         }
2225         var buf = new StringBuilder(length);
2226         dateTime.formatTo(buf);
2227         buf.append(offsetStr);
2228         if (zoneStr != null) {
2229             buf.append('[').append(zoneStr).append(']');
2230         }
2231         return buf.toString();
2232     }
2233 
2234     //-----------------------------------------------------------------------
2235     /**
2236      * Writes the object using a
2237      * <a href="{@docRoot}/serialized-form.html#java.time.Ser">dedicated serialized form</a>.
2238      * @serialData
2239      * <pre>
2240      *  out.writeByte(6);  // identifies a ZonedDateTime
2241      *  // the <a href="{@docRoot}/serialized-form.html#java.time.LocalDateTime">dateTime</a> excluding the one byte header
2242      *  // the <a href="{@docRoot}/serialized-form.html#java.time.ZoneOffset">offset</a> excluding the one byte header
2243      *  // the <a href="{@docRoot}/serialized-form.html#java.time.ZoneId">zone ID</a> excluding the one byte header
2244      * </pre>
2245      *
2246      * @return the instance of {@code Ser}, not null
2247      */
2248     @java.io.Serial
2249     private Object writeReplace() {
2250         return new Ser(Ser.ZONE_DATE_TIME_TYPE, this);
2251     }
2252 
2253     /**
2254      * Defend against malicious streams.
2255      *
2256      * @param s the stream to read
2257      * @throws InvalidObjectException always
2258      */
2259     @java.io.Serial
2260     private void readObject(ObjectInputStream s) throws InvalidObjectException {
2261         throw new InvalidObjectException("Deserialization via serialization delegate");
2262     }
2263 
2264     void writeExternal(DataOutput out) throws IOException {
2265         dateTime.writeExternal(out);
2266         offset.writeExternal(out);
2267         zone.write(out);
2268     }
2269 
2270     static ZonedDateTime readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
2271         LocalDateTime dateTime = LocalDateTime.readExternal(in);
2272         ZoneOffset offset = ZoneOffset.readExternal(in);
2273         ZoneId zone = (ZoneId) Ser.read(in);
2274         return ZonedDateTime.ofLenient(dateTime, offset, zone);
2275     }
2276 
2277 }