1 /*
   2  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
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   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  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).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
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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
  53  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  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
  57  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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  59  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  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.util.Collections;
  70 import java.util.Map;
  71 
  72 /**
  73  * A set of date fields that provide access to Julian Days.
  74  * <p>
  75  * The Julian Day is a standard way of expressing date and time commonly used in the scientific community.
  76  * It is expressed as a decimal number of whole days where days start at midday.
  77  * This class represents variations on Julian Days that count whole days from midnight.
  78  * <p>
  79  * The fields are implemented relative to {@link ChronoField#EPOCH_DAY EPOCH_DAY}.
  80  * The fields are supported, and can be queried and set if {@code EPOCH_DAY} is available.
  81  * The fields work with all chronologies.
  82  *
  83  * <h3>Specification for implementors</h3>
  84  * This is an immutable and thread-safe class.
  85  *
  86  * @since 1.8
  87  */
  88 public final class JulianFields {
  89 
  90     /**
  91      * The offset from Julian to EPOCH DAY.
  92      */
  93     private static final long JULIAN_DAY_OFFSET = 2440588L;
  94 
  95     /**
  96      * Julian Day field.
  97      * <p>
  98      * This is an integer-based version of the Julian Day Number.
  99      * Julian Day is a well-known system that represents the count of whole days since day 0,
 100      * which is defined to be January 1, 4713 BCE in the Julian calendar, and -4713-11-24 Gregorian.
 101      * The field  has "JulianDay" as 'name', and 'DAYS' as 'baseUnit'.
 102      * The field always refers to the local date-time, ignoring the offset or zone.
 103      * <p>
 104      * For date-times, 'JULIAN_DAY.getFrom()' assumes the same value from
 105      * midnight until just before the next midnight.
 106      * When 'JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 107      * 'JULIAN_DAY.adjustInto()' and 'JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects that
 108      * can be converted into {@link ChronoField#EPOCH_DAY}.
 109      * A {@link DateTimeException} is thrown for any other type of object.
 110      * <p>
 111      * <h3>Astronomical and Scientific Notes</h3>
 112      * The standard astronomical definition uses a fraction to indicate the time-of-day,
 113      * thus 3.25 would represent the time 18:00, since days start at midday.
 114      * This implementation uses an integer and days starting at midnight.
 115      * The integer value for the Julian Day Number is the astronomical Julian Day value at midday
 116      * of the date in question.
 117      * This amounts to the astronomical Julian Day, rounded to an integer {@code JDN = floor(JD + 0.5)}.
 118      * <p>
 119      * <pre>
 120      *  | ISO date          |  Julian Day Number | Astronomical Julian Day |
 121      *  | 1970-01-01T00:00  |         2,440,588  |         2,440,587.5     |
 122      *  | 1970-01-01T06:00  |         2,440,588  |         2,440,587.75    |
 123      *  | 1970-01-01T12:00  |         2,440,588  |         2,440,588.0     |
 124      *  | 1970-01-01T18:00  |         2,440,588  |         2,440,588.25    |
 125      *  | 1970-01-02T00:00  |         2,440,589  |         2,440,588.5     |
 126      *  | 1970-01-02T06:00  |         2,440,589  |         2,440,588.75    |
 127      *  | 1970-01-02T12:00  |         2,440,589  |         2,440,589.0     |
 128      * </pre>
 129      * <p>
 130      * Julian Days are sometimes taken to imply Universal Time or UTC, but this
 131      * implementation always uses the Julian Day number for the local date,
 132      * regardless of the offset or time-zone.
 133      */
 134     public static final TemporalField JULIAN_DAY = Field.JULIAN_DAY;
 135 
 136     /**
 137      * Modified Julian Day field.
 138      * <p>
 139      * This is an integer-based version of the Modified Julian Day Number.
 140      * Modified Julian Day (MJD) is a well-known system that counts days continuously.
 141      * It is defined relative to astronomical Julian Day as  {@code MJD = JD - 2400000.5}.
 142      * Each Modified Julian Day runs from midnight to midnight.
 143      * The field always refers to the local date-time, ignoring the offset or zone.
 144      * <p>
 145      * For date-times, 'MODIFIED_JULIAN_DAY.getFrom()' assumes the same value from
 146      * midnight until just before the next midnight.
 147      * When 'MODIFIED_JULIAN_DAY.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 148      * 'MODIFIED_JULIAN_DAY.adjustInto()' and 'MODIFIED_JULIAN_DAY.getFrom()' only apply to {@code Temporal} objects
 149      * that can be converted into {@link ChronoField#EPOCH_DAY}.
 150      * A {@link DateTimeException} is thrown for any other type of object.
 151      * <p>
 152      * This implementation is an integer version of MJD with the decimal part rounded to floor.
 153      * <p>
 154      * <h3>Astronomical and Scientific Notes</h3>
 155      * <pre>
 156      *  | ISO date          | Modified Julian Day |      Decimal MJD |
 157      *  | 1970-01-01T00:00  |             40,587  |       40,587.0   |
 158      *  | 1970-01-01T06:00  |             40,587  |       40,587.25  |
 159      *  | 1970-01-01T12:00  |             40,587  |       40,587.5   |
 160      *  | 1970-01-01T18:00  |             40,587  |       40,587.75  |
 161      *  | 1970-01-02T00:00  |             40,588  |       40,588.0   |
 162      *  | 1970-01-02T06:00  |             40,588  |       40,588.25  |
 163      *  | 1970-01-02T12:00  |             40,588  |       40,588.5   |
 164      * </pre>
 165      * <p>
 166      * Modified Julian Days are sometimes taken to imply Universal Time or UTC, but this
 167      * implementation always uses the Modified Julian Day for the local date,
 168      * regardless of the offset or time-zone.
 169      */
 170     public static final TemporalField MODIFIED_JULIAN_DAY = Field.MODIFIED_JULIAN_DAY;
 171 
 172     /**
 173      * Rata Die field.
 174      * <p>
 175      * Rata Die counts whole days continuously starting day 1 at midnight at the beginning of 0001-01-01 (ISO).
 176      * The field always refers to the local date-time, ignoring the offset or zone.
 177      * <p>
 178      * For date-times, 'RATA_DIE.getFrom()' assumes the same value from
 179      * midnight until just before the next midnight.
 180      * When 'RATA_DIE.adjustInto()' is applied to a date-time, the time of day portion remains unaltered.
 181      * 'RATA_DIE.adjustInto()' and 'RATA_DIE.getFrom()' only apply to {@code Temporal} objects
 182      * that can be converted into {@link ChronoField#EPOCH_DAY}.
 183      * A {@link DateTimeException} is thrown for any other type of object.
 184      */
 185     public static final TemporalField RATA_DIE = Field.RATA_DIE;
 186 
 187     /**
 188      * Restricted constructor.
 189      */
 190     private JulianFields() {
 191         throw new AssertionError("Not instantiable");
 192     }
 193 
 194     /**
 195      * Implementation of JulianFields.  Each instance is a singleton.
 196      */
 197     private static enum Field implements TemporalField {
 198         JULIAN_DAY("JulianDay", DAYS, FOREVER, JULIAN_DAY_OFFSET),
 199         MODIFIED_JULIAN_DAY("ModifiedJulianDay", DAYS, FOREVER, 40587L),
 200         RATA_DIE("RataDie", DAYS, FOREVER, 719163L);
 201 
 202         private static final long serialVersionUID = -7501623920830201812L;
 203 
 204         private final transient String name;
 205         private final transient TemporalUnit baseUnit;
 206         private final transient TemporalUnit rangeUnit;
 207         private final transient ValueRange range;
 208         private final transient long offset;
 209 
 210         private Field(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, long offset) {
 211             this.name = name;
 212             this.baseUnit = baseUnit;
 213             this.rangeUnit = rangeUnit;
 214             this.range = ValueRange.of(-365243219162L + offset, 365241780471L + offset);
 215             this.offset = offset;
 216         }
 217 



















 218         //-----------------------------------------------------------------------
 219         @Override
 220         public String getName() {
 221             return name;
 222         }
 223 
 224         @Override
 225         public TemporalUnit getBaseUnit() {
 226             return baseUnit;
 227         }
 228 
 229         @Override
 230         public TemporalUnit getRangeUnit() {
 231             return rangeUnit;
 232         }
 233 
 234         @Override
 235         public ValueRange range() {
 236             return range;
 237         }
 238 
 239         //-----------------------------------------------------------------------
 240         @Override
 241         public boolean isSupportedBy(TemporalAccessor temporal) {
 242             return temporal.isSupported(EPOCH_DAY);
 243         }
 244 
 245         @Override
 246         public ValueRange rangeRefinedBy(TemporalAccessor temporal) {
 247             if (isSupportedBy(temporal) == false) {
 248                 throw new DateTimeException("Unsupported field: " + this);
 249             }
 250             return range();
 251         }
 252 
 253         @Override
 254         public long getFrom(TemporalAccessor temporal) {
 255             return temporal.getLong(EPOCH_DAY) + offset;
 256         }
 257 
 258         @SuppressWarnings("unchecked")
 259         @Override
 260         public <R extends Temporal> R adjustInto(R temporal, long newValue) {
 261             if (range().isValidValue(newValue) == false) {
 262                 throw new DateTimeException("Invalid value: " + name + " " + newValue);
 263             }
 264             return (R) temporal.with(EPOCH_DAY, Math.subtractExact(newValue, offset));
 265         }
 266 
 267         //-----------------------------------------------------------------------
 268         @Override
 269         public Map<TemporalField, Long> resolve(TemporalAccessor temporal, long value) {
 270             return Collections.<TemporalField, Long>singletonMap(EPOCH_DAY, Math.subtractExact(value, offset));













 271         }
 272 
 273         //-----------------------------------------------------------------------
 274         @Override
 275         public String toString() {
 276             return name;
 277         }
 278     }
 279 }
--- EOF ---