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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   5  * This code is free software; you can redistribute it and/or modify it
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   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
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  17  * You should have received a copy of the GNU General Public License version
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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
  51  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  52  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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  54  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  55  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  56  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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  60  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  61  */
  62 package java.time.temporal;
  63 
  64 import static java.time.temporal.ChronoField.EPOCH_DAY;
  65 import static java.time.temporal.ChronoUnit.DAYS;
  66 import static java.time.temporal.ChronoUnit.FOREVER;
  67 
  68 import java.time.DateTimeException;
  69 import java.time.chrono.ChronoLocalDate;
  70 import java.time.chrono.Chronology;
  71 import java.time.format.ResolverStyle;
  72 import java.util.Map;
  73 
  74 /**
  75  * A set of date fields that provide access to Julian Days.
  76  * <p>
  77  * The Julian Day is a standard way of expressing date and time commonly used in the scientific community.
  78  * It is expressed as a decimal number of whole days where days start at midday.
  79  * This class represents variations on Julian Days that count whole days from midnight.
  80  * <p>
  81  * The fields are implemented relative to {@link ChronoField#EPOCH_DAY EPOCH_DAY}.
  82  * The fields are supported, and can be queried and set if {@code EPOCH_DAY} is available.
  83  * The fields work with all chronologies.
  84  *
  85  * @implSpec
  86  * This is an immutable and thread-safe class.
  87  *
  88  * @since 1.8
  89  */
  90 public final class JulianFields {
  91 
  92     /**
  93      * The offset from Julian to EPOCH DAY.
  94      */
  95     private static final long JULIAN_DAY_OFFSET = 2440588L;
  96 
  97     /**
  98      * Julian Day field.
  99      * <p>
 100      * This is an integer-based version of the Julian Day Number.
 101      * Julian Day is a well-known system that represents the count of whole days since day 0,
 102      * which is defined to be January 1, 4713 BCE in the Julian calendar, and -4713-11-24 Gregorian.
 103      * The field  has "JulianDay" as 'name', and 'DAYS' as 'baseUnit'.
 104      * The field always refers to the local date-time, ignoring the offset or zone.
 105      * <p>
 106      * For date-times, 'JULIAN_DAY.getFrom()' assumes the same value from
 107      * midnight until just before the next midnight.
 108      * When 'JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 109      * 'JULIAN_DAY.adjustInto()' and 'JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects that
 110      * can be converted into {@link ChronoField#EPOCH_DAY}.
 111      * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object.
 112      * <p>
 113      * In the resolving phase of parsing, a date can be created from a Julian Day field.
 114      * In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode}
 115      * the Julian Day value is validated against the range of valid values.
 116      * In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs.
 117      *
 118      * <h3>Astronomical and Scientific Notes</h3>
 119      * The standard astronomical definition uses a fraction to indicate the time-of-day,
 120      * where each day is counted from midday to midday. For example,
 121      * a fraction of 0 represents midday, a fraction of 0.25
 122      * represents 18:00, a fraction of 0.5 represents midnight and a fraction
 123      * of 0.75 represents 06:00.
 124      * <p>
 125      * By contrast, this implementation has no fractional part, and counts
 126      * days from midnight to midnight.
 127      * This implementation uses an integer and days starting at midnight.
 128      * The integer value for the Julian Day Number is the astronomical Julian Day value at midday
 129      * of the date in question.
 130      * This amounts to the astronomical Julian Day, rounded to an integer {@code JDN = floor(JD + 0.5)}.
 131      *
 132      * <pre>
 133      *  | ISO date          |  Julian Day Number | Astronomical Julian Day |
 134      *  | 1970-01-01T00:00  |         2,440,588  |         2,440,587.5     |
 135      *  | 1970-01-01T06:00  |         2,440,588  |         2,440,587.75    |
 136      *  | 1970-01-01T12:00  |         2,440,588  |         2,440,588.0     |
 137      *  | 1970-01-01T18:00  |         2,440,588  |         2,440,588.25    |
 138      *  | 1970-01-02T00:00  |         2,440,589  |         2,440,588.5     |
 139      *  | 1970-01-02T06:00  |         2,440,589  |         2,440,588.75    |
 140      *  | 1970-01-02T12:00  |         2,440,589  |         2,440,589.0     |
 141      * </pre>
 142      * <p>
 143      * Julian Days are sometimes taken to imply Universal Time or UTC, but this
 144      * implementation always uses the Julian Day number for the local date,
 145      * regardless of the offset or time-zone.
 146      */
 147     public static final TemporalField JULIAN_DAY = Field.JULIAN_DAY;
 148 
 149     /**
 150      * Modified Julian Day field.
 151      * <p>
 152      * This is an integer-based version of the Modified Julian Day Number.
 153      * Modified Julian Day (MJD) is a well-known system that counts days continuously.
 154      * It is defined relative to astronomical Julian Day as  {@code MJD = JD - 2400000.5}.
 155      * Each Modified Julian Day runs from midnight to midnight.
 156      * The field always refers to the local date-time, ignoring the offset or zone.
 157      * <p>
 158      * For date-times, 'MODIFIED_JULIAN_DAY.getFrom()' assumes the same value from
 159      * midnight until just before the next midnight.
 160      * When 'MODIFIED_JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 161      * 'MODIFIED_JULIAN_DAY.adjustInto()' and 'MODIFIED_JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects
 162      * that can be converted into {@link ChronoField#EPOCH_DAY}.
 163      * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object.
 164      * <p>
 165      * This implementation is an integer version of MJD with the decimal part rounded to floor.
 166      * <p>
 167      * In the resolving phase of parsing, a date can be created from a Modified Julian Day field.
 168      * In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode}
 169      * the Modified Julian Day value is validated against the range of valid values.
 170      * In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs.
 171      *
 172      * <h3>Astronomical and Scientific Notes</h3>
 173      * <pre>
 174      *  | ISO date          | Modified Julian Day |      Decimal MJD |
 175      *  | 1970-01-01T00:00  |             40,587  |       40,587.0   |
 176      *  | 1970-01-01T06:00  |             40,587  |       40,587.25  |
 177      *  | 1970-01-01T12:00  |             40,587  |       40,587.5   |
 178      *  | 1970-01-01T18:00  |             40,587  |       40,587.75  |
 179      *  | 1970-01-02T00:00  |             40,588  |       40,588.0   |
 180      *  | 1970-01-02T06:00  |             40,588  |       40,588.25  |
 181      *  | 1970-01-02T12:00  |             40,588  |       40,588.5   |
 182      * </pre>
 183      *
 184      * Modified Julian Days are sometimes taken to imply Universal Time or UTC, but this
 185      * implementation always uses the Modified Julian Day for the local date,
 186      * regardless of the offset or time-zone.
 187      */
 188     public static final TemporalField MODIFIED_JULIAN_DAY = Field.MODIFIED_JULIAN_DAY;
 189 
 190     /**
 191      * Rata Die field.
 192      * <p>
 193      * Rata Die counts whole days continuously starting day 1 at midnight at the beginning of 0001-01-01 (ISO).
 194      * The field always refers to the local date-time, ignoring the offset or zone.
 195      * <p>
 196      * For date-times, 'RATA_DIE.getFrom()' assumes the same value from
 197      * midnight until just before the next midnight.
 198      * When 'RATA_DIE.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 199      * 'RATA_DIE.adjustInto()' and 'RATA_DIE.getFrom()' only apply to {@code Temporal} objects
 200      * that can be converted into {@link ChronoField#EPOCH_DAY}.
 201      * An {@link UnsupportedTemporalTypeException} is thrown for any other type of object.
 202      * <p>
 203      * In the resolving phase of parsing, a date can be created from a Rata Die field.
 204      * In {@linkplain ResolverStyle#STRICT strict mode} and {@linkplain ResolverStyle#SMART smart mode}
 205      * the Rata Die value is validated against the range of valid values.
 206      * In {@linkplain ResolverStyle#LENIENT lenient mode} no validation occurs.
 207      */
 208     public static final TemporalField RATA_DIE = Field.RATA_DIE;
 209 
 210     /**
 211      * Restricted constructor.
 212      */
 213     private JulianFields() {
 214         throw new AssertionError("Not instantiable");
 215     }
 216 
 217     /**
 218      * Implementation of JulianFields.  Each instance is a singleton.
 219      */
 220     private static enum Field implements TemporalField {
 221         JULIAN_DAY("JulianDay", DAYS, FOREVER, JULIAN_DAY_OFFSET),
 222         MODIFIED_JULIAN_DAY("ModifiedJulianDay", DAYS, FOREVER, 40587L),
 223         RATA_DIE("RataDie", DAYS, FOREVER, 719163L);
 224 
 225         private static final long serialVersionUID = -7501623920830201812L;
 226 
 227         private final transient String name;
 228         private final transient TemporalUnit baseUnit;
 229         private final transient TemporalUnit rangeUnit;
 230         private final transient ValueRange range;
 231         private final transient long offset;
 232 
 233         private Field(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, long offset) {
 234             this.name = name;
 235             this.baseUnit = baseUnit;
 236             this.rangeUnit = rangeUnit;
 237             this.range = ValueRange.of(-365243219162L + offset, 365241780471L + offset);
 238             this.offset = offset;
 239         }
 240 
 241         //-----------------------------------------------------------------------
 242         @Override
 243         public TemporalUnit getBaseUnit() {
 244             return baseUnit;
 245         }
 246 
 247         @Override
 248         public TemporalUnit getRangeUnit() {
 249             return rangeUnit;
 250         }
 251 
 252         @Override
 253         public boolean isDateBased() {
 254             return true;
 255         }
 256 
 257         @Override
 258         public boolean isTimeBased() {
 259             return false;
 260         }
 261 
 262         @Override
 263         public ValueRange range() {
 264             return range;
 265         }
 266 
 267         //-----------------------------------------------------------------------
 268         @Override
 269         public boolean isSupportedBy(TemporalAccessor temporal) {
 270             return temporal.isSupported(EPOCH_DAY);
 271         }
 272 
 273         @Override
 274         public ValueRange rangeRefinedBy(TemporalAccessor temporal) {
 275             if (isSupportedBy(temporal) == false) {
 276                 throw new DateTimeException("Unsupported field: " + this);
 277             }
 278             return range();
 279         }
 280 
 281         @Override
 282         public long getFrom(TemporalAccessor temporal) {
 283             return temporal.getLong(EPOCH_DAY) + offset;
 284         }
 285 
 286         @SuppressWarnings("unchecked")
 287         @Override
 288         public <R extends Temporal> R adjustInto(R temporal, long newValue) {
 289             if (range().isValidValue(newValue) == false) {
 290                 throw new DateTimeException("Invalid value: " + name + " " + newValue);
 291             }
 292             return (R) temporal.with(EPOCH_DAY, Math.subtractExact(newValue, offset));
 293         }
 294 
 295         //-----------------------------------------------------------------------
 296         @Override
 297         public ChronoLocalDate resolve(
 298                 Map<TemporalField, Long> fieldValues, TemporalAccessor partialTemporal, ResolverStyle resolverStyle) {
 299             long value = fieldValues.remove(this);
 300             Chronology chrono = Chronology.from(partialTemporal);
 301             if (resolverStyle == ResolverStyle.LENIENT) {
 302                 return chrono.dateEpochDay(Math.subtractExact(value, offset));
 303             }
 304             range().checkValidValue(value, this);
 305             return chrono.dateEpochDay(value - offset);
 306         }
 307 
 308         //-----------------------------------------------------------------------
 309         @Override
 310         public String toString() {
 311             return name;
 312         }
 313     }
 314 }