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/*

 * Copyright (c) 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.

 *

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

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

 *    and/or other materials provided with the distribution.

 *

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

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

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

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

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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

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 */

package java.time.chrono;

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

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

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

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

import java.io.Serializable;

import java.time.DateTimeException;

import java.time.LocalDate;

import java.time.LocalTime;

import java.time.chrono.Chronology;

import java.time.chrono.ChronoLocalDate;

import java.time.chrono.ChronoLocalDateTime;

import java.time.temporal.ChronoUnit;

import java.time.temporal.Temporal;

import java.time.temporal.TemporalAdjuster;

import java.time.temporal.TemporalUnit;

/**

 * A date expressed in terms of a standard year-month-day calendar system.

 * <p>

 * This class is used by applications seeking to handle dates in non-ISO calendar systems.

 * For example, the Japanese, Minguo, Thai Buddhist and others.

 * <p>

 * {@code ChronoLocalDate} is built on the generic concepts of year, month and day.

 * The calendar system, represented by a {@link java.time.chrono.Chronology}, expresses the relationship between

 * the fields and this class allows the resulting date to be manipulated.

 * <p>

 * Note that not all calendar systems are suitable for use with this class.

 * For example, the Mayan calendar uses a system that bears no relation to years, months and days.

 * <p>

 * The API design encourages the use of {@code LocalDate} for the majority of the application.

 * This includes code to read and write from a persistent data store, such as a database,

 * and to send dates and times across a network. The {@code ChronoLocalDate} instance is then used

 * at the user interface level to deal with localized input/output.

 *

 * <P>Example: </p>

 * <pre>

 *        System.out.printf("Example()%n");

 *        // Enumerate the list of available calendars and print today for each

 *        Set<Chronology> chronos = Chronology.getAvailableChronologies();

 *        for (Chronology chrono : chronos) {

 *            ChronoLocalDate<?> date = chrono.dateNow();

 *            System.out.printf("   %20s: %s%n", chrono.getID(), date.toString());

 *        }

 *

 *        // Print the Hijrah date and calendar

 *        ChronoLocalDate<?> date = Chronology.of("Hijrah").dateNow();

 *        int day = date.get(ChronoField.DAY_OF_MONTH);

 *        int dow = date.get(ChronoField.DAY_OF_WEEK);

 *        int month = date.get(ChronoField.MONTH_OF_YEAR);

 *        int year = date.get(ChronoField.YEAR);

 *        System.out.printf("  Today is %s %s %d-%s-%d%n", date.getChronology().getID(),

 *                dow, day, month, year);

 *        // Print today's date and the last day of the year

 *        ChronoLocalDate<?> now1 = Chronology.of("Hijrah").dateNow();

 *        ChronoLocalDate<?> first = now1.with(ChronoField.DAY_OF_MONTH, 1)

 *                .with(ChronoField.MONTH_OF_YEAR, 1);

 *        ChronoLocalDate<?> last = first.plus(1, ChronoUnit.YEARS)

 *                .minus(1, ChronoUnit.DAYS);

 *        System.out.printf("  Today is %s: start: %s; end: %s%n", last.getChronology().getID(),

 *                first, last);

 * </pre>

 *

 * <h3>Adding Calendars</h3>

 * <p> The set of calendars is extensible by defining a subclass of {@link ChronoLocalDate}

 * to represent a date instance and an implementation of {@code Chronology}

 * to be the factory for the ChronoLocalDate subclass.

 * </p>

 * <p> To permit the discovery of the additional calendar types the implementation of

 * {@code Chronology} must be registered as a Service implementing the {@code Chronology} interface

 * in the {@code META-INF/Services} file as per the specification of {@link java.util.ServiceLoader}.

 * The subclass must function according to the {@code Chronology} class description and must provide its

 * {@link java.time.chrono.Chronology#getId() chronlogy ID} and {@link Chronology#getCalendarType() calendar type}. </p>

 *

 * <h3>Specification for implementors</h3>

 * This abstract class must be implemented with care to ensure other classes operate correctly.

 * All implementations that can be instantiated must be final, immutable and thread-safe.

 * Subclasses should be Serializable wherever possible.

 *

 * @param <D> the ChronoLocalDate of this date-time

 * @since 1.8

 */

abstract class ChronoDateImpl<D extends ChronoLocalDate<D>>

        implements ChronoLocalDate<D>, Temporal, TemporalAdjuster, Serializable {

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 6282433883239719096L;

    /**

     * Creates an instance.

     */

    ChronoDateImpl() {

    }

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

    @Override

    public D plus(long amountToAdd, TemporalUnit unit) {

        if (unit instanceof ChronoUnit) {

            ChronoUnit f = (ChronoUnit) unit;

            switch (f) {

                case DAYS: return plusDays(amountToAdd);

                case WEEKS: return plusDays(Math.multiplyExact(amountToAdd, 7));

                case MONTHS: return plusMonths(amountToAdd);

                case YEARS: return plusYears(amountToAdd);

                case DECADES: return plusYears(Math.multiplyExact(amountToAdd, 10));

                case CENTURIES: return plusYears(Math.multiplyExact(amountToAdd, 100));

                case MILLENNIA: return plusYears(Math.multiplyExact(amountToAdd, 1000));

                case ERAS: return with(ERA, Math.addExact(getLong(ERA), amountToAdd));

            }

            throw new DateTimeException("Unsupported unit: " + unit.getName());

        }

        return ChronoLocalDate.super.plus(amountToAdd, unit);

    }

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

    /**

     * Returns a copy of this date with the specified period in years added.

     * <p>

     * This adds the specified period in years to the date.

     * In some cases, adding years can cause the resulting date to become invalid.

     * If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure

     * that the result is valid. Typically this will select the last valid day of the month.

     * <p>

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

     *

     * @param yearsToAdd  the years to add, may be negative

     * @return a date based on this one with the years added, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    abstract D plusYears(long yearsToAdd);

    /**

     * Returns a copy of this date with the specified period in months added.

     * <p>

     * This adds the specified period in months to the date.

     * In some cases, adding months can cause the resulting date to become invalid.

     * If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure

     * that the result is valid. Typically this will select the last valid day of the month.

     * <p>

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

     *

     * @param monthsToAdd  the months to add, may be negative

     * @return a date based on this one with the months added, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    abstract D plusMonths(long monthsToAdd);

    /**

     * Returns a copy of this date with the specified period in weeks added.

     * <p>

     * This adds the specified period in weeks to the date.

     * In some cases, adding weeks can cause the resulting date to become invalid.

     * If this occurs, then other fields will be adjusted to ensure that the result is valid.

     * <p>

     * The default implementation uses {@link #plusDays(long)} using a 7 day week.

     * <p>

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

     *

     * @param weeksToAdd  the weeks to add, may be negative

     * @return a date based on this one with the weeks added, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    D plusWeeks(long weeksToAdd) {

        return plusDays(Math.multiplyExact(weeksToAdd, 7));

    }

    /**

     * Returns a copy of this date with the specified number of days added.

     * <p>

     * This adds the specified period in days to the date.

     * <p>

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

     *

     * @param daysToAdd  the days to add, may be negative

     * @return a date based on this one with the days added, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    abstract D plusDays(long daysToAdd);

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

    /**

     * Returns a copy of this date with the specified period in years subtracted.

     * <p>

     * This subtracts the specified period in years to the date.

     * In some cases, subtracting years can cause the resulting date to become invalid.

     * If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure

     * that the result is valid. Typically this will select the last valid day of the month.

     * <p>

     * The default implementation uses {@link #plusYears(long)}.

     * <p>

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

     *

     * @param yearsToSubtract  the years to subtract, may be negative

     * @return a date based on this one with the years subtracted, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    D minusYears(long yearsToSubtract) {

        return (yearsToSubtract == Long.MIN_VALUE ? ((ChronoDateImpl<D>)plusYears(Long.MAX_VALUE)).plusYears(1) : plusYears(-yearsToSubtract));

    }

    /**

     * Returns a copy of this date with the specified period in months subtracted.

     * <p>

     * This subtracts the specified period in months to the date.

     * In some cases, subtracting months can cause the resulting date to become invalid.

     * If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure

     * that the result is valid. Typically this will select the last valid day of the month.

     * <p>

     * The default implementation uses {@link #plusMonths(long)}.

     * <p>

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

     *

     * @param monthsToSubtract  the months to subtract, may be negative

     * @return a date based on this one with the months subtracted, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    D minusMonths(long monthsToSubtract) {

        return (monthsToSubtract == Long.MIN_VALUE ? ((ChronoDateImpl<D>)plusMonths(Long.MAX_VALUE)).plusMonths(1) : plusMonths(-monthsToSubtract));

    }

    /**

     * Returns a copy of this date with the specified period in weeks subtracted.

     * <p>

     * This subtracts the specified period in weeks to the date.

     * In some cases, subtracting weeks can cause the resulting date to become invalid.

     * If this occurs, then other fields will be adjusted to ensure that the result is valid.

     * <p>

     * The default implementation uses {@link #plusWeeks(long)}.

     * <p>

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

     *

     * @param weeksToSubtract  the weeks to subtract, may be negative

     * @return a date based on this one with the weeks subtracted, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    D minusWeeks(long weeksToSubtract) {

        return (weeksToSubtract == Long.MIN_VALUE ? ((ChronoDateImpl<D>)plusWeeks(Long.MAX_VALUE)).plusWeeks(1) : plusWeeks(-weeksToSubtract));

    }

    /**

     * Returns a copy of this date with the specified number of days subtracted.

     * <p>

     * This subtracts the specified period in days to the date.

     * <p>

     * The default implementation uses {@link #plusDays(long)}.

     * <p>

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

     *

     * @param daysToSubtract  the days to subtract, may be negative

     * @return a date based on this one with the days subtracted, not null

     * @throws DateTimeException if the result exceeds the supported date range

     */

    D minusDays(long daysToSubtract) {

        return (daysToSubtract == Long.MIN_VALUE ? ((ChronoDateImpl<D>)plusDays(Long.MAX_VALUE)).plusDays(1) : plusDays(-daysToSubtract));

    }

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

    /**

     * {@inheritDoc}

     * @throws DateTimeException {@inheritDoc}

     * @throws ArithmeticException {@inheritDoc}

     */

    @Override

    public long periodUntil(Temporal endDateTime, TemporalUnit unit) {

        if (endDateTime instanceof ChronoLocalDate == false) {

            throw new DateTimeException("Unable to calculate period between objects of two different types");

        }

        ChronoLocalDate<?> end = (ChronoLocalDate<?>) endDateTime;

        if (getChronology().equals(end.getChronology()) == false) {

            throw new DateTimeException("Unable to calculate period between two different chronologies");

        }

        if (unit instanceof ChronoUnit) {

            return LocalDate.from(this).periodUntil(end, unit);  // TODO: this is wrong

        }

        return unit.between(this, endDateTime);

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof ChronoLocalDate) {

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

        }

        return false;

    }

    @Override

    public int hashCode() {

        long epDay = toEpochDay();

        return getChronology().hashCode() ^ ((int) (epDay ^ (epDay >>> 32)));

    }

    @Override

    public String toString() {

        // getLong() reduces chances of exceptions in toString()

        long yoe = getLong(YEAR_OF_ERA);

        long moy = getLong(MONTH_OF_YEAR);

        long dom = getLong(DAY_OF_MONTH);

        StringBuilder buf = new StringBuilder(30);

        buf.append(getChronology().toString())

                .append(" ")

                .append(getEra())

                .append(" ")

                .append(yoe)

                .append(moy < 10 ? "-0" : "-").append(moy)

                .append(dom < 10 ? "-0" : "-").append(dom);

        return buf.toString();

    }

}