001/*
002 * Copyright (c) 2007-2013, Stephen Colebourne & Michael Nascimento Santos
003 *
004 * All rights reserved.
005 *
006 * Redistribution and use in source and binary forms, with or without
007 * modification, are permitted provided that the following conditions are met:
008 *
009 *  * Redistributions of source code must retain the above copyright notice,
010 *    this list of conditions and the following disclaimer.
011 *
012 *  * Redistributions in binary form must reproduce the above copyright notice,
013 *    this list of conditions and the following disclaimer in the documentation
014 *    and/or other materials provided with the distribution.
015 *
016 *  * Neither the name of JSR-310 nor the names of its contributors
017 *    may be used to endorse or promote products derived from this software
018 *    without specific prior written permission.
019 *
020 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
021 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
022 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
023 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
024 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
025 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
026 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
027 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
028 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
029 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
030 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
031 */
032package org.threeten.bp.temporal;
033
034import static org.threeten.bp.temporal.ChronoField.EPOCH_DAY;
035import static org.threeten.bp.temporal.ChronoUnit.DAYS;
036import static org.threeten.bp.temporal.ChronoUnit.FOREVER;
037
038import org.threeten.bp.DateTimeException;
039import org.threeten.bp.LocalDate;
040import org.threeten.bp.format.DateTimeBuilder;
041import org.threeten.bp.jdk8.Jdk8Methods;
042
043/**
044 * A set of date fields that provide access to Julian Days.
045 * <p>
046 * The Julian Day is a standard way of expressing date and time commonly used in the scientific community.
047 * It is expressed as a decimal number of whole days where days start at midday.
048 * This class represents variations on Julian Days that count whole days from midnight.
049 *
050 * <h3>Specification for implementors</h3>
051 * This is an immutable and thread-safe class.
052 */
053public final class JulianFields {
054
055    /**
056     * Julian Day field.
057     * <p>
058     * This is an integer-based version of the Julian Day Number.
059     * Julian Day is a well-known system that represents the count of whole days since day 0,
060     * which is defined to be January 1, 4713 BCE in the Julian calendar, and -4713-11-24 Gregorian.
061     * The field  has "JulianDay" as 'name', and 'DAYS' as 'baseUnit'.
062     * The field always refers to the local date-time, ignoring the offset or zone.
063     * <p>
064     * For date-times, 'JULIAN_DAY.doGet()' assumes the same value from
065     * midnight until just before the next midnight.
066     * When 'JULIAN_DAY.doWith()' is applied to a date-time, the time of day portion remains unaltered.
067     * 'JULIAN_DAY.doWith()' and 'JULIAN_DAY.doGet()' only apply to {@code Temporal} objects that
068     * can be converted into {@link ChronoField#EPOCH_DAY}.
069     * A {@link DateTimeException} is thrown for any other type of object.
070     * <p>
071     * <h3>Astronomical and Scientific Notes</h3>
072     * The standard astronomical definition uses a fraction to indicate the time-of-day,
073     * thus 3.25 would represent the time 18:00, since days start at midday.
074     * This implementation uses an integer and days starting at midnight.
075     * The integer value for the Julian Day Number is the astronomical Julian Day value at midday
076     * of the date in question.
077     * This amounts to the astronomical Julian Day, rounded to an integer {@code JDN = floor(JD + 0.5)}.
078     * <p>
079     * <pre>
080     *  | ISO date          |  Julian Day Number | Astronomical Julian Day |
081     *  | 1970-01-01T00:00  |         2,440,588  |         2,440,587.5     |
082     *  | 1970-01-01T06:00  |         2,440,588  |         2,440,587.75    |
083     *  | 1970-01-01T12:00  |         2,440,588  |         2,440,588.0     |
084     *  | 1970-01-01T18:00  |         2,440,588  |         2,440,588.25    |
085     *  | 1970-01-02T00:00  |         2,440,589  |         2,440,588.5     |
086     *  | 1970-01-02T06:00  |         2,440,589  |         2,440,588.75    |
087     *  | 1970-01-02T12:00  |         2,440,589  |         2,440,589.0     |
088     * </pre>
089     * <p>
090     * Julian Days are sometimes taken to imply Universal Time or UTC, but this
091     * implementation always uses the Julian Day number for the local date,
092     * regardless of the offset or time-zone.
093     */
094    public static final TemporalField JULIAN_DAY = Field.JULIAN_DAY;
095    /**
096     * Modified Julian Day field.
097     * <p>
098     * This is an integer-based version of the Modified Julian Day Number.
099     * Modified Julian Day (MJD) is a well-known system that counts days continuously.
100     * It is defined relative to astronomical Julian Day as  {@code MJD = JD - 2400000.5}.
101     * Each Modified Julian Day runs from midnight to midnight.
102     * The field always refers to the local date-time, ignoring the offset or zone.
103     * <p>
104     * For date-times, 'MODIFIED_JULIAN_DAY.doGet()' assumes the same value from
105     * midnight until just before the next midnight.
106     * When 'MODIFIED_JULIAN_DAY.doWith()' is applied to a date-time, the time of day portion remains unaltered.
107     * 'MODIFIED_JULIAN_DAY.doWith()' and 'MODIFIED_JULIAN_DAY.doGet()' only apply to {@code Temporal} objects
108     * that can be converted into {@link ChronoField#EPOCH_DAY}.
109     * A {@link DateTimeException} is thrown for any other type of object.
110     * <p>
111     * This implementation is an integer version of MJD with the decimal part rounded to floor.
112     * <p>
113     * <h3>Astronomical and Scientific Notes</h3>
114     * <pre>
115     *  | ISO date          | Modified Julian Day |      Decimal MJD |
116     *  | 1970-01-01T00:00  |             40,587  |       40,587.0   |
117     *  | 1970-01-01T06:00  |             40,587  |       40,587.25  |
118     *  | 1970-01-01T12:00  |             40,587  |       40,587.5   |
119     *  | 1970-01-01T18:00  |             40,587  |       40,587.75  |
120     *  | 1970-01-02T00:00  |             40,588  |       40,588.0   |
121     *  | 1970-01-02T06:00  |             40,588  |       40,588.25  |
122     *  | 1970-01-02T12:00  |             40,588  |       40,588.5   |
123     * </pre>
124     * <p>
125     * Modified Julian Days are sometimes taken to imply Universal Time or UTC, but this
126     * implementation always uses the Modified Julian Day for the local date,
127     * regardless of the offset or time-zone.
128     */
129    public static final TemporalField MODIFIED_JULIAN_DAY = Field.MODIFIED_JULIAN_DAY;
130    /**
131     * Rata Die field.
132     * <p>
133     * Rata Die counts whole days continuously starting day 1 at midnight at the beginning of 0001-01-01 (ISO).
134     * The field always refers to the local date-time, ignoring the offset or zone.
135     * <p>
136     * For date-times, 'RATA_DIE.doGet()' assumes the same value from
137     * midnight until just before the next midnight.
138     * When 'RATA_DIE.doWith()' is applied to a date-time, the time of day portion remains unaltered.
139     * 'MODIFIED_JULIAN_DAY.doWith()' and 'RATA_DIE.doGet()' only apply to {@code Temporal} objects
140     * that can be converted into {@link ChronoField#EPOCH_DAY}.
141     * A {@link DateTimeException} is thrown for any other type of object.
142     */
143    public static final TemporalField RATA_DIE = Field.RATA_DIE;
144
145    /**
146     * Hidden implementation.
147     */
148    private static enum Field implements TemporalField {
149        /**
150         * Julian Day field.
151         */
152        // 719163L + 1721425L = 2440588L
153        JULIAN_DAY("JulianDay", DAYS, FOREVER, 2440588L),
154        /**
155         * Modified Julian Day field.
156         */
157        // 719163L - 678576L = 40587L
158        MODIFIED_JULIAN_DAY("ModifiedJulianDay", DAYS, FOREVER, 40587L),
159        /**
160         * Rata Die field.
161         */
162        RATA_DIE("RataDie", DAYS, FOREVER, 719163L),
163        // lots of others Truncated,Lilian, ANSI COBOL (also dotnet related), Excel?
164        ;
165
166        private final String name;
167        private final TemporalUnit baseUnit;
168        private final TemporalUnit rangeUnit;
169        private final ValueRange range;
170        private final long offset;
171
172        private Field(String name, TemporalUnit baseUnit, TemporalUnit rangeUnit, long offset) {
173            this.name = name;
174            this.baseUnit = baseUnit;
175            this.rangeUnit = rangeUnit;
176            this.range = ValueRange.of(-365243219162L + offset, 365241780471L + offset);
177            this.offset = offset;
178        }
179
180        //-----------------------------------------------------------------------
181        @Override
182        public String getName() {
183            return name;
184        }
185
186        @Override
187        public TemporalUnit getBaseUnit() {
188            return baseUnit;
189        }
190
191        @Override
192        public TemporalUnit getRangeUnit() {
193            return rangeUnit;
194        }
195
196        @Override
197        public ValueRange range() {
198            return range;
199        }
200
201        @Override
202        public int compare(TemporalAccessor temporal1, TemporalAccessor temporal2) {
203            return Long.compare(temporal1.getLong(this), temporal2.getLong(this));
204        }
205
206        //-----------------------------------------------------------------------
207        @Override
208        public boolean doIsSupported(TemporalAccessor temporal) {
209            return temporal.isSupported(EPOCH_DAY);
210        }
211
212        @Override
213        public ValueRange doRange(TemporalAccessor temporal) {
214            if (doIsSupported(temporal) == false) {
215                throw new DateTimeException("Unsupported field: " + this);
216            }
217            return range();
218        }
219
220        @Override
221        public long doGet(TemporalAccessor temporal) {
222            return temporal.getLong(EPOCH_DAY) + offset;
223        }
224
225        @Override
226        public <R extends Temporal> R doWith(R dateTime, long newValue) {
227            if (range().isValidValue(newValue) == false) {
228                throw new DateTimeException("Invalid value: " + name + " " + newValue);
229            }
230            return (R) dateTime.with(EPOCH_DAY, Jdk8Methods.safeSubtract(newValue, offset));
231        }
232
233        //-----------------------------------------------------------------------
234        @Override
235        public boolean resolve(DateTimeBuilder builder, long value) {
236            boolean changed = false;
237            changed = resolve0(JULIAN_DAY, builder, changed);
238            changed = resolve0(MODIFIED_JULIAN_DAY, builder, changed);
239            changed = resolve0(RATA_DIE, builder, changed);
240            return changed;
241        }
242
243        private boolean resolve0(Field field, DateTimeBuilder builder, boolean changed) {
244            if (builder.containsFieldValue(field)) {
245                builder.addCalendrical(LocalDate.ofEpochDay(Jdk8Methods.safeSubtract(builder.getFieldValue(JULIAN_DAY), JULIAN_DAY.offset)));
246                builder.removeFieldValue(JULIAN_DAY);
247                changed = true;
248            }
249            return changed;
250        }
251
252        //-----------------------------------------------------------------------
253        @Override
254        public String toString() {
255            return getName();
256        }
257
258    }
259}