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
6 * under the terms of the GNU General Public License version 2 only, as
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
23 * questions.
24 */
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
58 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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 }