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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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package java.time.chrono;

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

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.Instant;

import java.time.LocalDateTime;

import java.time.ZoneId;

import java.time.ZoneOffset;

import java.time.temporal.ChronoField;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Temporal;

import java.time.temporal.TemporalField;

import java.time.temporal.TemporalUnit;

import java.time.zone.ZoneOffsetTransition;

import java.time.zone.ZoneRules;

import java.util.List;

import java.util.Objects;

/**

 * A date-time with a time-zone in the calendar neutral API.

 * <p>

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

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

 * as well as a time-zone and zone offset.

 * <p>

 * The purpose of storing the time-zone is to distinguish the ambiguous case where

 * the local time-line overlaps, typically as a result of the end of daylight time.

 * Information about the local-time can be obtained using methods on the time-zone.

 *

 * @implSpec

 * This class is immutable and thread-safe.

 *

 * @serial Document the delegation of this class in the serialized-form specification.

 * @param <D> the concrete type for the date of this date-time

 * @since 1.8

 */

final class ChronoZonedDateTimeImpl<D extends ChronoLocalDate>

        implements ChronoZonedDateTime<D>, Serializable {

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = -5261813987200935591L;

    /**

     * The local date-time.

     */

    private final transient ChronoLocalDateTimeImpl<D> dateTime;

    /**

     * The zone offset.

     */

    private final transient ZoneOffset offset;

    /**

     * The zone ID.

     */

    private final transient ZoneId zone;

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

    /**

     * Obtains an instance from a local date-time using the preferred offset if possible.

     *

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

     * @param zone  the zone identifier, not null

     * @param preferredOffset  the zone offset, null if no preference

     * @return the zoned date-time, not null

     */

    static <R extends ChronoLocalDate> ChronoZonedDateTime<R> ofBest(

            ChronoLocalDateTimeImpl<R> localDateTime, ZoneId zone, ZoneOffset preferredOffset) {

        Objects.requireNonNull(localDateTime, "localDateTime");

        Objects.requireNonNull(zone, "zone");

        if (zone instanceof ZoneOffset) {

            return new ChronoZonedDateTimeImpl<>(localDateTime, (ZoneOffset) zone, zone);

        }

        ZoneRules rules = zone.getRules();

        LocalDateTime isoLDT = LocalDateTime.from(localDateTime);

        List<ZoneOffset> validOffsets = rules.getValidOffsets(isoLDT);

        ZoneOffset offset;

        if (validOffsets.size() == 1) {

            offset = validOffsets.get(0);

        } else if (validOffsets.size() == 0) {

            ZoneOffsetTransition trans = rules.getTransition(isoLDT);

            localDateTime = localDateTime.plusSeconds(trans.getDuration().getSeconds());

            offset = trans.getOffsetAfter();

        } else {

            if (preferredOffset != null && validOffsets.contains(preferredOffset)) {

                offset = preferredOffset;

            } else {

                offset = validOffsets.get(0);

            }

        }

        Objects.requireNonNull(offset, "offset");  // protect against bad ZoneRules

        return new ChronoZonedDateTimeImpl<>(localDateTime, offset, zone);

    }

    /**

     * Obtains an instance from an instant using the specified time-zone.

     *

     * @param chrono  the chronology, not null

     * @param instant  the instant, not null

     * @param zone  the zone identifier, not null

     * @return the zoned date-time, not null

     */

    static ChronoZonedDateTimeImpl<?> ofInstant(Chronology chrono, Instant instant, ZoneId zone) {

        ZoneRules rules = zone.getRules();

        ZoneOffset offset = rules.getOffset(instant);

        Objects.requireNonNull(offset, "offset");  // protect against bad ZoneRules

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

        ChronoLocalDateTimeImpl<?> cldt = (ChronoLocalDateTimeImpl<?>)chrono.localDateTime(ldt);

        return new ChronoZonedDateTimeImpl<>(cldt, offset, zone);

    }

    /**

     * Obtains an instance from an {@code Instant}.

     *

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

     * @param zone  the time-zone to use, validated not null

     * @return the zoned date-time, validated not null

     */

    @SuppressWarnings("unchecked")

    private ChronoZonedDateTimeImpl<D> create(Instant instant, ZoneId zone) {

        return (ChronoZonedDateTimeImpl<D>)ofInstant(getChronology(), instant, zone);

    }

    /**

     * Casts the {@code Temporal} to {@code ChronoZonedDateTimeImpl} ensuring it bas the specified chronology.

     *

     * @param chrono  the chronology to check for, not null

     * @param temporal  a date-time to cast, not null

     * @return the date-time checked and cast to {@code ChronoZonedDateTimeImpl}, not null

     * @throws ClassCastException if the date-time cannot be cast to ChronoZonedDateTimeImpl

     *  or the chronology is not equal this Chronology

     */

    static <R extends ChronoLocalDate> ChronoZonedDateTimeImpl<R> ensureValid(Chronology chrono, Temporal temporal) {

        @SuppressWarnings("unchecked")

        ChronoZonedDateTimeImpl<R> other = (ChronoZonedDateTimeImpl<R>) temporal;

        if (chrono.equals(other.getChronology()) == false) {

            throw new ClassCastException("Chronology mismatch, required: " + chrono.getId()

                    + ", actual: " + other.getChronology().getId());

        }

        return other;

    }

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

    /**

     * Constructor.

     *

     * @param dateTime  the date-time, not null

     * @param offset  the zone offset, not null

     * @param zone  the zone ID, not null

     */

    private ChronoZonedDateTimeImpl(ChronoLocalDateTimeImpl<D> dateTime, ZoneOffset offset, ZoneId zone) {

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

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

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

    }

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

    @Override

    public ZoneOffset getOffset() {

        return offset;

    }

    @Override

    public ChronoZonedDateTime<D> withEarlierOffsetAtOverlap() {

        ZoneOffsetTransition trans = getZone().getRules().getTransition(LocalDateTime.from(this));

        if (trans != null && trans.isOverlap()) {

            ZoneOffset earlierOffset = trans.getOffsetBefore();

            if (earlierOffset.equals(offset) == false) {

                return new ChronoZonedDateTimeImpl<>(dateTime, earlierOffset, zone);

            }

        }

        return this;

    }

    @Override

    public ChronoZonedDateTime<D> withLaterOffsetAtOverlap() {

        ZoneOffsetTransition trans = getZone().getRules().getTransition(LocalDateTime.from(this));

        if (trans != null) {

            ZoneOffset offset = trans.getOffsetAfter();

            if (offset.equals(getOffset()) == false) {

                return new ChronoZonedDateTimeImpl<>(dateTime, offset, zone);

            }

        }

        return this;

    }

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

    @Override

    public ChronoLocalDateTime<D> toLocalDateTime() {

        return dateTime;

    }

    @Override

    public ZoneId getZone() {

        return zone;

    }

    @Override

    public ChronoZonedDateTime<D> withZoneSameLocal(ZoneId zone) {

        return ofBest(dateTime, zone, offset);

    }

    @Override

    public ChronoZonedDateTime<D> withZoneSameInstant(ZoneId zone) {

        Objects.requireNonNull(zone, "zone");

        return this.zone.equals(zone) ? this : create(dateTime.toInstant(offset), zone);

    }

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

    @Override

    public boolean isSupported(TemporalField field) {

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

    }

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

    @Override

    public ChronoZonedDateTime<D> with(TemporalField field, long newValue) {

        if (field instanceof ChronoField) {

            ChronoField f = (ChronoField) field;

            switch (f) {

                case INSTANT_SECONDS: return plus(newValue - toEpochSecond(), SECONDS);

                case OFFSET_SECONDS: {

                    ZoneOffset offset = ZoneOffset.ofTotalSeconds(f.checkValidIntValue(newValue));

                    return create(dateTime.toInstant(offset), zone);

                }

            }

            return ofBest(dateTime.with(field, newValue), zone, offset);

        }

        return ChronoZonedDateTimeImpl.ensureValid(getChronology(), field.adjustInto(this, newValue));

    }

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

    @Override

    public ChronoZonedDateTime<D> plus(long amountToAdd, TemporalUnit unit) {

        if (unit instanceof ChronoUnit) {

            return with(dateTime.plus(amountToAdd, unit));

        }

        return ChronoZonedDateTimeImpl.ensureValid(getChronology(), unit.addTo(this, amountToAdd));   /// TODO: Generics replacement Risk!

    }

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

    @Override

    public long until(Temporal endExclusive, TemporalUnit unit) {

        Objects.requireNonNull(endExclusive, "endExclusive");

        @SuppressWarnings("unchecked")

        ChronoZonedDateTime<D> end = (ChronoZonedDateTime<D>) getChronology().zonedDateTime(endExclusive);

        if (unit instanceof ChronoUnit) {

            end = end.withZoneSameInstant(offset);

            return dateTime.until(end.toLocalDateTime(), unit);

        }

        Objects.requireNonNull(unit, "unit");

        return unit.between(this, end);

    }

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

    /**

     * Writes the ChronoZonedDateTime using a

     * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.

     * @serialData

     * <pre>

     *  out.writeByte(3);                  // identifies a ChronoZonedDateTime

     *  out.writeObject(toLocalDateTime());

     *  out.writeObject(getOffset());

     *  out.writeObject(getZone());

     * </pre>

     *

     * @return the instance of {@code Ser}, not null

     */

    private Object writeReplace() {

        return new Ser(Ser.CHRONO_ZONE_DATE_TIME_TYPE, this);

    }

    /**

     * Defend against malicious streams.

     * @return never

     * @throws InvalidObjectException always

     */

    private Object readResolve() throws InvalidObjectException {

        throw new InvalidObjectException("Deserialization via serialization delegate");

    }

    void writeExternal(ObjectOutput out) throws IOException {

        out.writeObject(dateTime);

        out.writeObject(offset);

        out.writeObject(zone);

    }

    static ChronoZonedDateTime<?> readExternal(ObjectInput in) throws IOException, ClassNotFoundException {

        ChronoLocalDateTime<?> dateTime = (ChronoLocalDateTime<?>) in.readObject();

        ZoneOffset offset = (ZoneOffset) in.readObject();

        ZoneId zone = (ZoneId) in.readObject();

        return dateTime.atZone(offset).withZoneSameLocal(zone);

        // TODO: ZDT uses ofLenient()

    }

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

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof ChronoZonedDateTime) {

            return compareTo((ChronoZonedDateTime<?>) obj) == 0;

        }

        return false;

    }

    @Override

    public int hashCode() {

        return toLocalDateTime().hashCode() ^ getOffset().hashCode() ^ Integer.rotateLeft(getZone().hashCode(), 3);

    }

    @Override

    public String toString() {

        String str = toLocalDateTime().toString() + getOffset().toString();

        if (getOffset() != getZone()) {

            str += '[' + getZone().toString() + ']';

        }

        return str;

    }

}