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     13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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     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) 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
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     61  */
     62 
     63 /**
     64  * <p>
     65  * Generic API for calendar systems other than the default ISO.
     66  * </p>
     67  * <p>
     68  * The main API is based around the calendar system defined in ISO-8601.
     69  * However, there are other calendar systems, and this package provides basic support for them.
     70  * The alternate calendars are provided in the {@link java.time.chrono} package.
     71  * </p>
     72  * <p>
     73  * A calendar system is defined by the {@link java.time.chrono.Chronology} interface,
     74  * while a date in a calendar system is defined by the {@link java.time.chrono.ChronoLocalDate} interface.
     75  * </p>
     76  * <p>
     77  * It is intended that applications use the main API whenever possible, including code to read and write
     78  * from a persistent data store, such as a database, and to send dates and times across a network.
     79  * The "chrono" classes are then used at the user interface level to deal with localized input/output.
     80  * See {@link java.time.chrono.ChronoLocalDate ChronoLocalDate}
     81  * for a full discussion of the issues.
     82  * </p>
     83  * <p>
     84  * Using non-ISO calendar systems in an application introduces significant extra complexity.
     85  * Ensure that the warnings and recommendations in {@code ChronoLocalDate} have been read before
     86  * working with the "chrono" interfaces.
     87  * </p>
     88  * <p>
     89  * The supported calendar systems includes:
     90  * </p>
     91  * <ul>
     92  * <li>{@link java.time.chrono.HijrahChronology Hijrah calendar}</li>
     93  * <li>{@link java.time.chrono.JapaneseChronology Japanese calendar}</li>
     94  * <li>{@link java.time.chrono.MinguoChronology Minguo calendar}</li>
     95  * <li>{@link java.time.chrono.ThaiBuddhistChronology Thai Buddhist calendar}</li>
     96  * </ul>
     97  *
     98  * <h3>Example</h3>
     99  * <p>
    100  * This example lists todays date for all of the available calendars.
    101  * </p>
    102  * <pre>
    103  *   // Enumerate the list of available calendars and print todays date for each.
    104  *       Set&lt;Chronology&gt; chronos = Chronology.getAvailableChronologies();
    105  *       for (Chronology chrono : chronos) {
    106  *           ChronoLocalDate date = chrono.dateNow();
    107  *           System.out.printf("   %20s: %s%n", chrono.getId(), date.toString());
    108  *       }
    109  * </pre>
    110  *
    111  * <p>
    112  * This example creates and uses a date in a named non-ISO calendar system.
    113  * </p>
    114  * <pre>
    115  *   // Print the Thai Buddhist date
    116  *       ChronoLocalDate now1 = Chronology.of("ThaiBuddhist").dateNow();
    117  *       int day = now1.get(ChronoField.DAY_OF_MONTH);
    118  *       int dow = now1.get(ChronoField.DAY_OF_WEEK);
    119  *       int month = now1.get(ChronoField.MONTH_OF_YEAR);
    120  *       int year = now1.get(ChronoField.YEAR);
    121  *       System.out.printf("  Today is %s %s %d-%s-%d%n", now1.getChronology().getId(),
    122  *                 dow, day, month, year);
    123  *   // Print today's date and the last day of the year for the Thai Buddhist Calendar.
    124  *       ChronoLocalDate first = now1
    125  *                 .with(ChronoField.DAY_OF_MONTH, 1)
    126  *                 .with(ChronoField.MONTH_OF_YEAR, 1);
    127  *       ChronoLocalDate last = first
    128  *                 .plus(1, ChronoUnit.YEARS)
    129  *                 .minus(1, ChronoUnit.DAYS);
    130  *       System.out.printf("  %s: 1st of year: %s; end of year: %s%n", last.getChronology().getId(),
    131  *                 first, last);
    132  *  </pre>
    133  *
    134  * <p>
    135  * This example creates and uses a date in a specific ThaiBuddhist calendar system.
    136  * </p>
    137  * <pre>
    138  *   // Print the Thai Buddhist date
    139  *       ThaiBuddhistDate now1 = ThaiBuddhistDate.now();
    140  *       int day = now1.get(ChronoField.DAY_OF_MONTH);
    141  *       int dow = now1.get(ChronoField.DAY_OF_WEEK);
    142  *       int month = now1.get(ChronoField.MONTH_OF_YEAR);
    143  *       int year = now1.get(ChronoField.YEAR);
    144  *       System.out.printf("  Today is %s %s %d-%s-%d%n", now1.getChronology().getId(),
    145  *                 dow, day, month, year);
    146  *
    147  *   // Print today's date and the last day of the year for the Thai Buddhist Calendar.
    148  *       ThaiBuddhistDate first = now1
    149  *                 .with(ChronoField.DAY_OF_MONTH, 1)
    150  *                 .with(ChronoField.MONTH_OF_YEAR, 1);
    151  *       ThaiBuddhistDate last = first
    152  *                 .plus(1, ChronoUnit.YEARS)
    153  *                 .minus(1, ChronoUnit.DAYS);
    154  *       System.out.printf("  %s: 1st of year: %s; end of year: %s%n", last.getChronology().getId(),
    155  *                 first, last);
    156  *  </pre>
    157  *
    158  * <h3>Package specification</h3>
    159  * <p>
    160  * Unless otherwise noted, passing a null argument to a constructor or method in any class or interface
    161  * in this package will cause a {@link java.lang.NullPointerException NullPointerException} to be thrown.
    162  * The Javadoc "@param" definition is used to summarise the null-behavior.
    163  * The "@throws {@link java.lang.NullPointerException}" is not explicitly documented in each method.
    164  * </p>
    165  * <p>
    166  * All calculations should check for numeric overflow and throw either an {@link java.lang.ArithmeticException}
    167  * or a {@link java.time.DateTimeException}.
    168  * </p>
    169  * @since JDK1.8
    170  */
    171 package java.time.chrono;
    172