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/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

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 *  * Redistributions in binary form must reproduce the above copyright notice,

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 *    and/or other materials provided with the distribution.

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 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

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 */

package java.time;

import static java.time.temporal.ChronoField.EPOCH_DAY;

import static java.time.temporal.ChronoField.INSTANT_SECONDS;

import static java.time.temporal.ChronoField.NANO_OF_DAY;

import static java.time.temporal.ChronoField.OFFSET_SECONDS;

import static java.time.temporal.ChronoUnit.FOREVER;

import static java.time.temporal.ChronoUnit.NANOS;

import java.io.IOException;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.Serializable;

import java.time.chrono.IsoChronology;

import java.time.format.DateTimeFormatter;

import java.time.format.DateTimeParseException;

import java.time.temporal.ChronoField;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Temporal;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.TemporalAdjuster;

import java.time.temporal.TemporalAmount;

import java.time.temporal.TemporalField;

import java.time.temporal.TemporalQueries;

import java.time.temporal.TemporalQuery;

import java.time.temporal.TemporalUnit;

import java.time.temporal.UnsupportedTemporalTypeException;

import java.time.temporal.ValueRange;

import java.time.zone.ZoneRules;

import java.util.Comparator;

import java.util.Objects;

/**

 * A date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system,

 * such as {@code 2007-12-03T10:15:30+01:00}.

 * <p>

 * {@code OffsetDateTime} is an immutable representation of a date-time with an offset.

 * This class stores all date and time fields, to a precision of nanoseconds,

 * as well as the offset from UTC/Greenwich. For example, the value

 * "2nd October 2007 at 13:45:30.123456789 +02:00" can be stored in an {@code OffsetDateTime}.

 * <p>

 * {@code OffsetDateTime}, {@link java.time.ZonedDateTime} and {@link java.time.Instant} all store an instant

 * on the time-line to nanosecond precision.

 * {@code Instant} is the simplest, simply representing the instant.

 * {@code OffsetDateTime} adds to the instant the offset from UTC/Greenwich, which allows

 * the local date-time to be obtained.

 * {@code ZonedDateTime} adds full time-zone rules.

 * <p>

 * It is intended that {@code ZonedDateTime} or {@code Instant} is used to model data

 * in simpler applications. This class may be used when modeling date-time concepts in

 * more detail, or when communicating to a database or in a network protocol.

 *

 * <p>

 * class; use of identity-sensitive operations (including reference equality

 * ({@code ==}), identity hash code, or synchronization) on instances of

 * {@code OffsetDateTime} may have unpredictable results and should be avoided.

 * The {@code equals} method should be used for comparisons.

 *

 * @implSpec

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class OffsetDateTime

        implements Temporal, TemporalAdjuster, Comparable<OffsetDateTime>, Serializable {

    /**

     * The minimum supported {@code OffsetDateTime}, '-999999999-01-01T00:00:00+18:00'.

     * This is the local date-time of midnight at the start of the minimum date

     * in the maximum offset (larger offsets are earlier on the time-line).

     * This combines {@link LocalDateTime#MIN} and {@link ZoneOffset#MAX}.

     * This could be used by an application as a "far past" date-time.

     */

    public static final OffsetDateTime MIN = LocalDateTime.MIN.atOffset(ZoneOffset.MAX);

    /**

     * The maximum supported {@code OffsetDateTime}, '+999999999-12-31T23:59:59.999999999-18:00'.

     * This is the local date-time just before midnight at the end of the maximum date

     * in the minimum offset (larger negative offsets are later on the time-line).

     * This combines {@link LocalDateTime#MAX} and {@link ZoneOffset#MIN}.

     * This could be used by an application as a "far future" date-time.

     */

    public static final OffsetDateTime MAX = LocalDateTime.MAX.atOffset(ZoneOffset.MIN);

    /**

     * Gets a comparator that compares two {@code OffsetDateTime} instances

     * based solely on the instant.

     * <p>

     * This method differs from the comparison in {@link #compareTo} in that it

     * only compares the underlying instant.

     *

     * @return a comparator that compares in time-line order

     *

     * @see #isAfter

     * @see #isBefore

     * @see #isEqual

     */

    public static Comparator<OffsetDateTime> timeLineOrder() {

        return OffsetDateTime::compareInstant;

    }

    /**

     * Compares this {@code OffsetDateTime} to another date-time.

     * The comparison is based on the instant.

     *

     * @param datetime1  the first date-time to compare, not null

     * @param datetime2  the other date-time to compare to, not null

     * @return the comparator value, negative if less, positive if greater

     */

    private static int compareInstant(OffsetDateTime datetime1, OffsetDateTime datetime2) {

        if (datetime1.getOffset().equals(datetime2.getOffset())) {

            return datetime1.toLocalDateTime().compareTo(datetime2.toLocalDateTime());

        }

        int cmp = Long.compare(datetime1.toEpochSecond(), datetime2.toEpochSecond());

        if (cmp == 0) {

            cmp = datetime1.toLocalTime().getNano() - datetime2.toLocalTime().getNano();

        }

        return cmp;

    }

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 2287754244819255394L;

    /**

     * The local date-time.

     */

    private final LocalDateTime dateTime;

    /**

     * The offset from UTC/Greenwich.

     */

    private final ZoneOffset offset;

    //-----------------------------------------------------------------------

    /**

     * Obtains the current date-time from the system clock in the default time-zone.

     * <p>

     * This will query the {@link Clock#systemDefaultZone() system clock} in the default

     * time-zone to obtain the current date-time.

     * The offset will be calculated from the time-zone in the clock.

     * <p>

     * Using this method will prevent the ability to use an alternate clock for testing

     * because the clock is hard-coded.

     *

     * @return the current date-time using the system clock, not null

     */

    public static OffsetDateTime now() {

        return now(Clock.systemDefaultZone());

    }

    /**

     * Obtains the current date-time from the system clock in the specified time-zone.

     * <p>

     * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date-time.

     * Specifying the time-zone avoids dependence on the default time-zone.

     * The offset will be calculated from the specified time-zone.

     * <p>

     * Using this method will prevent the ability to use an alternate clock for testing

     * because the clock is hard-coded.

     *

     * @param zone  the zone ID to use, not null

     * @return the current date-time using the system clock, not null

     */

    public static OffsetDateTime now(ZoneId zone) {

        return now(Clock.system(zone));

    }

    /**

     * Obtains the current date-time from the specified clock.

     * <p>

     * This will query the specified clock to obtain the current date-time.

     * The offset will be calculated from the time-zone in the clock.

     * <p>

     * Using this method allows the use of an alternate clock for testing.

     * The alternate clock may be introduced using {@link Clock dependency injection}.

     *

     * @param clock  the clock to use, not null

     * @return the current date-time, not null

     */

    public static OffsetDateTime now(Clock clock) {

        Objects.requireNonNull(clock, "clock");

        final Instant now = clock.instant();  // called once

        return ofInstant(now, clock.getZone().getRules().getOffset(now));

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code OffsetDateTime} from a date, time and offset.

     * <p>

     * This creates an offset date-time with the specified local date, time and offset.

     *

     * @param date  the local date, not null

     * @param time  the local time, not null

     * @param offset  the zone offset, not null

     * @return the offset date-time, not null

     */

    public static OffsetDateTime of(LocalDate date, LocalTime time, ZoneOffset offset) {

        LocalDateTime dt = LocalDateTime.of(date, time);

        return new OffsetDateTime(dt, offset);

    }

    /**

     * Obtains an instance of {@code OffsetDateTime} from a date-time and offset.

     * <p>

     * This creates an offset date-time with the specified local date-time and offset.

     *

     * @param dateTime  the local date-time, not null

     * @param offset  the zone offset, not null

     * @return the offset date-time, not null

     */

    public static OffsetDateTime of(LocalDateTime dateTime, ZoneOffset offset) {

        return new OffsetDateTime(dateTime, offset);

    }

    /**

     * Obtains an instance of {@code OffsetDateTime} from a year, month, day,

     * hour, minute, second, nanosecond and offset.

     * <p>

     * This creates an offset date-time with the seven specified fields.

     * <p>

     * This method exists primarily for writing test cases.

     * Non test-code will typically use other methods to create an offset time.

     * {@code LocalDateTime} has five additional convenience variants of the

     * equivalent factory method taking fewer arguments.

     * They are not provided here to reduce the footprint of the API.

     *

     * @param year  the year to represent, from MIN_YEAR to MAX_YEAR

     * @param month  the month-of-year to represent, from 1 (January) to 12 (December)

     * @param dayOfMonth  the day-of-month to represent, from 1 to 31

     * @param hour  the hour-of-day to represent, from 0 to 23

     * @param minute  the minute-of-hour to represent, from 0 to 59

     * @param second  the second-of-minute to represent, from 0 to 59

     * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999

     * @param offset  the zone offset, not null

     * @return the offset date-time, not null

     * @throws DateTimeException if the value of any field is out of range, or

     *  if the day-of-month is invalid for the month-year

     */

    public static OffsetDateTime of(

            int year, int month, int dayOfMonth,

            int hour, int minute, int second, int nanoOfSecond, ZoneOffset offset) {

        LocalDateTime dt = LocalDateTime.of(year, month, dayOfMonth, hour, minute, second, nanoOfSecond);

        return new OffsetDateTime(dt, offset);

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code OffsetDateTime} from an {@code Instant} and zone ID.

     * <p>

     * This creates an offset date-time with the same instant as that specified.

     * Finding the offset from UTC/Greenwich is simple as there is only one valid

     * offset for each instant.

     *

     * @param instant  the instant to create the date-time from, not null

     * @param zone  the time-zone, which may be an offset, not null

     * @return the offset date-time, not null

     * @throws DateTimeException if the result exceeds the supported range

     */

    public static OffsetDateTime ofInstant(Instant instant, ZoneId zone) {

        Objects.requireNonNull(instant, "instant");

        Objects.requireNonNull(zone, "zone");

        ZoneRules rules = zone.getRules();

        ZoneOffset offset = rules.getOffset(instant);

        LocalDateTime ldt = LocalDateTime.ofEpochSecond(instant.getEpochSecond(), instant.getNano(), offset);

        return new OffsetDateTime(ldt, offset);

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code OffsetDateTime} from a temporal object.

     * <p>

     * This obtains an offset date-time based on the specified temporal.

     * A {@code TemporalAccessor} represents an arbitrary set of date and time information,

     * which this factory converts to an instance of {@code OffsetDateTime}.

     * <p>

     * The conversion will first obtain a {@code ZoneOffset} from the temporal object.

     * It will then try to obtain a {@code LocalDateTime}, falling back to an {@code Instant} if necessary.

     * The result will be the combination of {@code ZoneOffset} with either

     * with {@code LocalDateTime} or {@code Instant}.

     * Implementations are permitted to perform optimizations such as accessing

     * those fields that are equivalent to the relevant objects.

     * <p>

     * This method matches the signature of the functional interface {@link TemporalQuery}

     * allowing it to be used as a query via method reference, {@code OffsetDateTime::from}.

     *

     * @param temporal  the temporal object to convert, not null

     * @return the offset date-time, not null

     * @throws DateTimeException if unable to convert to an {@code OffsetDateTime}

     */

    public static OffsetDateTime from(TemporalAccessor temporal) {

        if (temporal instanceof OffsetDateTime) {

            return (OffsetDateTime) temporal;

        }

        try {

            ZoneOffset offset = ZoneOffset.from(temporal);

            LocalDate date = temporal.query(TemporalQueries.localDate());

            LocalTime time = temporal.query(TemporalQueries.localTime());

            if (date != null && time != null) {

                return OffsetDateTime.of(date, time, offset);

            } else {

                Instant instant = Instant.from(temporal);

                return OffsetDateTime.ofInstant(instant, offset);

            }

        } catch (DateTimeException ex) {

            throw new DateTimeException("Unable to obtain OffsetDateTime from TemporalAccessor: " +

                    temporal + " of type " + temporal.getClass().getName(), ex);

        }

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains an instance of {@code OffsetDateTime} from a text string

     * such as {@code 2007-12-03T10:15:30+01:00}.

     * <p>

     * The string must represent a valid date-time and is parsed using

     * {@link java.time.format.DateTimeFormatter#ISO_OFFSET_DATE_TIME}.

     *

     * @param text  the text to parse such as "2007-12-03T10:15:30+01:00", not null

     * @return the parsed offset date-time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

    public static OffsetDateTime parse(CharSequence text) {

        return parse(text, DateTimeFormatter.ISO_OFFSET_DATE_TIME);

    }

    /**

     * Obtains an instance of {@code OffsetDateTime} from a text string using a specific formatter.

     * <p>

     * The text is parsed using the formatter, returning a date-time.

     *

     * @param text  the text to parse, not null

     * @param formatter  the formatter to use, not null

     * @return the parsed offset date-time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

    public static OffsetDateTime parse(CharSequence text, DateTimeFormatter formatter) {

        Objects.requireNonNull(formatter, "formatter");

        return formatter.parse(text, OffsetDateTime::from);

    }

    //-----------------------------------------------------------------------

    /**

     * Constructor.

     *

     * @param dateTime  the local date-time, not null

     * @param offset  the zone offset, not null

     */

    private OffsetDateTime(LocalDateTime dateTime, ZoneOffset offset) {

        this.dateTime = Objects.requireNonNull(dateTime, "dateTime");

        this.offset = Objects.requireNonNull(offset, "offset");

    }

    /**

     * Returns a new date-time based on this one, returning {@code this} where possible.

     *

     * @param dateTime  the date-time to create with, not null

     * @param offset  the zone offset to create with, not null

     */

    private OffsetDateTime with(LocalDateTime dateTime, ZoneOffset offset) {

        if (this.dateTime == dateTime && this.offset.equals(offset)) {

            return this;

        }

        return new OffsetDateTime(dateTime, offset);

    }

    //-----------------------------------------------------------------------

    /**

     * Checks if the specified field is supported.

     * <p>

     * This checks if this date-time can be queried for the specified field.

     * If false, then calling the {@link #range(TemporalField) range},

     * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}

     * methods will throw an exception.

     * <p>

     * If the field is a {@link ChronoField} then the query is implemented here.

     * The supported fields are:

     * <ul>

     * <li>{@code NANO_OF_SECOND}

     * <li>{@code NANO_OF_DAY}

     * <li>{@code MICRO_OF_SECOND}

     * <li>{@code MICRO_OF_DAY}

     * <li>{@code MILLI_OF_SECOND}

     * <li>{@code MILLI_OF_DAY}

     * <li>{@code SECOND_OF_MINUTE}

     * <li>{@code SECOND_OF_DAY}

     * <li>{@code MINUTE_OF_HOUR}

     * <li>{@code MINUTE_OF_DAY}

     * <li>{@code HOUR_OF_AMPM}

     * <li>{@code CLOCK_HOUR_OF_AMPM}

     * <li>{@code HOUR_OF_DAY}

     * <li>{@code CLOCK_HOUR_OF_DAY}

     * <li>{@code AMPM_OF_DAY}

     * <li>{@code DAY_OF_WEEK}

     * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}

     * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}

     * <li>{@code DAY_OF_MONTH}

     * <li>{@code DAY_OF_YEAR}

     * <li>{@code EPOCH_DAY}

     * <li>{@code ALIGNED_WEEK_OF_MONTH}

     * <li>{@code ALIGNED_WEEK_OF_YEAR}

     * <li>{@code MONTH_OF_YEAR}

     * <li>{@code PROLEPTIC_MONTH}

     * <li>{@code YEAR_OF_ERA}

     * <li>{@code YEAR}

     * <li>{@code ERA}

     * <li>{@code INSTANT_SECONDS}

     * <li>{@code OFFSET_SECONDS}

     * </ul>

     * All other {@code ChronoField} instances will return false.

     * <p>

     * If the field is not a {@code ChronoField}, then the result of this method

     * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}

     * passing {@code this} as the argument.

     * Whether the field is supported is determined by the field.

     *

     * @param field  the field to check, null returns false

     * @return true if the field is supported on this date-time, false if not

     */

    @Override

    public boolean isSupported(TemporalField field) {

        return field instanceof ChronoField || (field != null && field.isSupportedBy(this));

    }

    /**

     * Checks if the specified unit is supported.

     * <p>

     * This checks if the specified unit can be added to, or subtracted from, this date-time.

     * If false, then calling the {@link #plus(long, TemporalUnit)} and

     * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.

     * <p>

     * If the unit is a {@link ChronoUnit} then the query is implemented here.

     * The supported units are:

     * <ul>

     * <li>{@code NANOS}

     * <li>{@code MICROS}

     * <li>{@code MILLIS}

     * <li>{@code SECONDS}

     * <li>{@code MINUTES}

     * <li>{@code HOURS}

     * <li>{@code HALF_DAYS}

     * <li>{@code DAYS}

     * <li>{@code WEEKS}

     * <li>{@code MONTHS}

     * <li>{@code YEARS}

     * <li>{@code DECADES}

     * <li>{@code CENTURIES}

     * <li>{@code MILLENNIA}

     * <li>{@code ERAS}

     * </ul>

     * All other {@code ChronoUnit} instances will return false.

     * <p>

     * If the unit is not a {@code ChronoUnit}, then the result of this method

     * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}

     * passing {@code this} as the argument.

     * Whether the unit is supported is determined by the unit.

     *