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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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 *    this list of conditions and the following disclaimer in the documentation

 *    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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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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 */

package java.time;

import static java.time.LocalTime.NANOS_PER_HOUR;

import static java.time.LocalTime.NANOS_PER_MINUTE;

import static java.time.LocalTime.NANOS_PER_SECOND;

import static java.time.LocalTime.SECONDS_PER_DAY;

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

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

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

import java.io.IOException;

import java.io.InvalidObjectException;

import java.io.ObjectInput;

import java.io.ObjectOutput;

import java.io.ObjectStreamException;

import java.io.Serializable;

import java.time.format.DateTimeFormatter;

import java.time.format.DateTimeParseException;

import java.time.temporal.ChronoField;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Queries;

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.TemporalQuery;

import java.time.temporal.TemporalUnit;

import java.time.temporal.ValueRange;

import java.time.zone.ZoneRules;

import java.util.Objects;

/**

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

 * such as {@code 10:15:30+01:00}.

 * <p>

 * {@code OffsetTime} is an immutable date-time object that represents a time, often

 * viewed as hour-minute-second-offset.

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

 * as well as a zone offset.

 * For example, the value "13:45.30.123456789+02:00" can be stored

 * in an {@code OffsetTime}.

 *

 * <h3>Specification for implementors</h3>

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class OffsetTime

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

    /**

     * The minimum supported {@code OffsetTime}, '00:00:00+18:00'.

     * This is the time of midnight at the start of the day in the maximum offset

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

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

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

     */

    public static final OffsetTime MIN = LocalTime.MIN.atOffset(ZoneOffset.MAX);

    /**

     * The maximum supported {@code OffsetTime}, '23:59:59.999999999-18:00'.

     * This is the time just before midnight at the end of the day in the minimum offset

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

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

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

     */

    public static final OffsetTime MAX = LocalTime.MAX.atOffset(ZoneOffset.MIN);

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 7264499704384272492L;

    /**

     * The local date-time.

     */

    private final LocalTime time;

    /**

     * The offset from UTC/Greenwich.

     */

    private final ZoneOffset offset;

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

    /**

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

     * <p>

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

     * time-zone to obtain the current 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 time using the system clock, not null

     */

    public static OffsetTime now() {

        return now(Clock.systemDefaultZone());

    }

    /**

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

     * <p>

     * This will query the {@link Clock#system(java.time.ZoneId) system clock} to obtain the current 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 time using the system clock, not null

     */

    public static OffsetTime now(ZoneId zone) {

        return now(Clock.system(zone));

    }

    /**

     * Obtains the current time from the specified clock.

     * <p>

     * This will query the specified clock to obtain the current 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 time, not null

     */

    public static OffsetTime 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 OffsetTime} from a local time and an offset.

     *

     * @param time  the local time, not null

     * @param offset  the zone offset, not null

     * @return the offset time, not null

     */

    public static OffsetTime of(LocalTime time, ZoneOffset offset) {

        return new OffsetTime(time, offset);

    }

    /**

     * Obtains an instance of {@code OffsetTime} from an hour, minute, second and nanosecond.

     * <p>

     * This creates an offset time with the four 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 LocalTime} has two additional convenience variants of the

     * equivalent factory method taking fewer arguments.

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

     *

     * @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 time, not null

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

     */

    public static OffsetTime of(int hour, int minute, int second, int nanoOfSecond, ZoneOffset offset) {

        return new OffsetTime(LocalTime.of(hour, minute, second, nanoOfSecond), offset);

    }

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

    /**

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

     * <p>

     * This creates an offset 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.

     * <p>

     * The date component of the instant is dropped during the conversion.

     * This means that the conversion can never fail due to the instant being

     * out of the valid range of dates.

     *

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

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

     * @return the offset time, not null

     */

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

        Objects.requireNonNull(instant, "instant");

        Objects.requireNonNull(zone, "zone");

        ZoneRules rules = zone.getRules();

        ZoneOffset offset = rules.getOffset(instant);

        long localSecond = instant.getEpochSecond() + offset.getTotalSeconds();  // overflow caught later

        int secsOfDay = (int) Math.floorMod(localSecond, SECONDS_PER_DAY);

        LocalTime time = LocalTime.ofNanoOfDay(secsOfDay * NANOS_PER_SECOND + instant.getNano());

        return new OffsetTime(time, offset);

    }

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

    /**

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

     * <p>

     * This obtains an offset 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 OffsetTime}.

     * <p>

     * The conversion extracts and combines the {@code ZoneOffset} and the

     * {@code LocalTime} from the temporal object.

     * 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 in queries via method reference, {@code OffsetTime::from}.

     *

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

     * @return the offset time, not null

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

     */

    public static OffsetTime from(TemporalAccessor temporal) {

        if (temporal instanceof OffsetTime) {

            return (OffsetTime) temporal;

        }

        try {

            LocalTime time = LocalTime.from(temporal);

            ZoneOffset offset = ZoneOffset.from(temporal);

            return new OffsetTime(time, offset);

        } catch (DateTimeException ex) {

            throw new DateTimeException("Unable to obtain OffsetTime from TemporalAccessor: " + temporal.getClass(), ex);

        }

    }

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

    /**

     * Obtains an instance of {@code OffsetTime} from a text string such as {@code 10:15:30+01:00}.

     * <p>

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

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

     *

     * @param text  the text to parse such as "10:15:30+01:00", not null

     * @return the parsed local time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

    public static OffsetTime parse(CharSequence text) {

        return parse(text, DateTimeFormatter.ISO_OFFSET_TIME);

    }

    /**

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

     * <p>

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

     *

     * @param text  the text to parse, not null

     * @param formatter  the formatter to use, not null

     * @return the parsed offset time, not null

     * @throws DateTimeParseException if the text cannot be parsed

     */

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

        Objects.requireNonNull(formatter, "formatter");

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

    }

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

    /**

     * Constructor.

     *

     * @param time  the local time, not null

     * @param offset  the zone offset, not null

     */

    private OffsetTime(LocalTime time, ZoneOffset offset) {

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

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

    }

    /**

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

     *

     * @param time  the time to create with, not null

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

     */

    private OffsetTime with(LocalTime time, ZoneOffset offset) {

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

            return this;

        }

        return new OffsetTime(time, offset);

    }

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

    /**

     * Checks if the specified field is supported.

     * <p>

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

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

     * {@link #get(TemporalField) get} 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 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 time, false if not

     */

    @Override

    public boolean isSupported(TemporalField field) {

        if (field instanceof ChronoField) {

            return ((ChronoField) field).isTimeField() || field == OFFSET_SECONDS;

        }

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

    }

    /**

     * Gets the range of valid values for the specified field.

     * <p>

     * The range object expresses the minimum and maximum valid values for a field.

     * This time is used to enhance the accuracy of the returned range.

     * If it is not possible to return the range, because the field is not supported

     * or for some other reason, an exception is thrown.

     * <p>

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

     * The {@link #isSupported(TemporalField) supported fields} will return

     * appropriate range instances.

     * All other {@code ChronoField} instances will throw a {@code DateTimeException}.

     * <p>

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

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

     * passing {@code this} as the argument.

     * Whether the range can be obtained is determined by the field.

     *

     * @param field  the field to query the range for, not null

     * @return the range of valid values for the field, not null

     * @throws DateTimeException if the range for the field cannot be obtained

     */

    @Override

    public ValueRange range(TemporalField field) {

        if (field instanceof ChronoField) {

            if (field == OFFSET_SECONDS) {

                return field.range();

            }

            return time.range(field);

        }

        return field.rangeRefinedBy(this);

    }

    /**

     * Gets the value of the specified field from this time as an {@code int}.

     * <p>

     * This queries this time for the value for the specified field.

     * The returned value will always be within the valid range of values for the field.

     * If it is not possible to return the value, because the field is not supported

     * or for some other reason, an exception is thrown.

     * <p>

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

     * The {@link #isSupported(TemporalField) supported fields} will return valid

     * values based on this time, except {@code NANO_OF_DAY} and {@code MICRO_OF_DAY}

     * which are too large to fit in an {@code int} and throw a {@code DateTimeException}.

     * All other {@code ChronoField} instances will throw a {@code DateTimeException}.

     * <p>

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

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

     * passing {@code this} as the argument. Whether the value can be obtained,

     * and what the value represents, is determined by the field.

     *

     * @param field  the field to get, not null

     * @return the value for the field

     * @throws DateTimeException if a value for the field cannot be obtained

     * @throws ArithmeticException if numeric overflow occurs

     */

    @Override  // override for Javadoc

    public int get(TemporalField field) {

        return Temporal.super.get(field);

    }

    /**

     * Gets the value of the specified field from this time as a {@code long}.

     * <p>

     * This queries this time for the value for the specified field.

     * If it is not possible to return the value, because the field is not supported

     * or for some other reason, an exception is thrown.

     * <p>

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

     * The {@link #isSupported(TemporalField) supported fields} will return valid

     * values based on this time.

     * All other {@code ChronoField} instances will throw a {@code DateTimeException}.

     * <p>

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

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

     * passing {@code this} as the argument. Whether the value can be obtained,

     * and what the value represents, is determined by the field.

     *

     * @param field  the field to get, not null

     * @return the value for the field

     * @throws DateTimeException if a value for the field cannot be obtained

     * @throws ArithmeticException if numeric overflow occurs

     */

    @Override

    public long getLong(TemporalField field) {

        if (field instanceof ChronoField) {

            if (field == OFFSET_SECONDS) {

                return offset.getTotalSeconds();

            }

            return time.getLong(field);

        }

        return field.getFrom(this);

    }

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

    /**

     * Gets the zone offset, such as '+01:00'.

     * <p>

     * This is the offset of the local time from UTC/Greenwich.

     *

     * @return the zone offset, not null

     */

    public ZoneOffset getOffset() {

        return offset;

    }

    /**

     * Returns a copy of this {@code OffsetTime} with the specified offset ensuring

     * that the result has the same local time.

     * <p>

     * This method returns an object with the same {@code LocalTime} and the specified {@code ZoneOffset}.

     * No calculation is needed or performed.

     * For example, if this time represents {@code 10:30+02:00} and the offset specified is

     * {@code +03:00}, then this method will return {@code 10:30+03:00}.

     * <p>

     * To take into account the difference between the offsets, and adjust the time fields,

     * use {@link #withOffsetSameInstant}.

     * <p>

     * This instance is immutable and unaffected by this method call.

     *

     * @param offset  the zone offset to change to, not null

     * @return an {@code OffsetTime} based on this time with the requested offset, not null

     */

    public OffsetTime withOffsetSameLocal(ZoneOffset offset) {

        return offset != null && offset.equals(this.offset) ? this : new OffsetTime(time, offset);

    }

    /**

     * Returns a copy of this {@code OffsetTime} with the specified offset ensuring

     * that the result is at the same instant on an implied day.

     * <p>

     * This method returns an object with the specified {@code ZoneOffset} and a {@code LocalTime}

     * adjusted by the difference between the two offsets.

     * This will result in the old and new objects representing the same instant an an implied day.

     * This is useful for finding the local time in a different offset.

     * For example, if this time represents {@code 10:30+02:00} and the offset specified is

     * {@code +03:00}, then this method will return {@code 11:30+03:00}.