1 /*
2 * Copyright (c) 2012, 2019, 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.chrono;
63
64 import static java.time.chrono.JapaneseDate.MEIJI_6_ISODATE;
65 import static java.time.temporal.ChronoField.ERA;
66
67 import java.io.DataInput;
68 import java.io.DataOutput;
69 import java.io.IOException;
70 import java.io.InvalidObjectException;
71 import java.io.ObjectInputStream;
72 import java.io.ObjectStreamException;
73 import java.io.Serializable;
74 import java.time.DateTimeException;
75 import java.time.LocalDate;
76 import java.time.format.DateTimeFormatterBuilder;
77 import java.time.format.TextStyle;
78 import java.time.temporal.ChronoField;
79 import java.time.temporal.TemporalField;
80 import java.time.temporal.UnsupportedTemporalTypeException;
81 import java.time.temporal.ValueRange;
82 import java.util.Arrays;
83 import java.util.Locale;
84 import java.util.Objects;
85
86 import sun.util.calendar.CalendarDate;
87
88 /**
89 * An era in the Japanese Imperial calendar system.
90 * <p>
91 * The Japanese government defines the official name and start date of
92 * each era. Eras are consecutive and their date ranges do not overlap,
93 * so the end date of one era is always the day before the start date
94 * of the next era.
95 * <p>
96 * The Java SE Platform supports all eras defined by the Japanese government,
97 * beginning with the Meiji era. Each era is identified in the Platform by an
98 * integer value and a name. The {@link #of(int)} and {@link #valueOf(String)}
99 * methods may be used to obtain a singleton instance of {@code JapaneseEra}
100 * for each era. The {@link #values()} method returns the singleton instances
101 * of all supported eras.
102 * <p>
103 * For convenience, this class declares a number of public static final fields
104 * that refer to singleton instances returned by the {@link #values()} method.
105 *
106 * @apiNote
107 * The fields declared in this class may evolve over time, in line with the
108 * results of the {@link #values()} method. However, there is not necessarily
109 * a 1:1 correspondence between the fields and the singleton instances.
110 *
111 * @apiNote
112 * The Japanese government may announce a new era and define its start
113 * date but not its official name. In this scenario, the singleton instance
114 * that represents the new era may return a name that is not stable until
115 * the official name is defined. Developers should exercise caution when
116 * relying on the name returned by any singleton instance that does not
117 * correspond to a public static final field.
118 *
119 * @implSpec
120 * This class is immutable and thread-safe.
121 *
122 * @since 1.8
123 */
124 public final class JapaneseEra
125 implements Era, Serializable {
126
127 // The offset value to 0-based index from the era value.
128 // i.e., getValue() + ERA_OFFSET == 0-based index
129 static final int ERA_OFFSET = 2;
130
131 static final sun.util.calendar.Era[] ERA_CONFIG;
132
133 /**
134 * The singleton instance for the 'Meiji' era (1868-01-01 - 1912-07-29)
135 * which has the value -1.
136 */
137 public static final JapaneseEra MEIJI = new JapaneseEra(-1, LocalDate.of(1868, 1, 1));
138 /**
139 * The singleton instance for the 'Taisho' era (1912-07-30 - 1926-12-24)
140 * which has the value 0.
141 */
142 public static final JapaneseEra TAISHO = new JapaneseEra(0, LocalDate.of(1912, 7, 30));
143 /**
144 * The singleton instance for the 'Showa' era (1926-12-25 - 1989-01-07)
145 * which has the value 1.
146 */
147 public static final JapaneseEra SHOWA = new JapaneseEra(1, LocalDate.of(1926, 12, 25));
148 /**
149 * The singleton instance for the 'Heisei' era (1989-01-08 - 2019-04-30)
150 * which has the value 2.
151 */
152 public static final JapaneseEra HEISEI = new JapaneseEra(2, LocalDate.of(1989, 1, 8));
153 /**
154 * The singleton instance for the 'Reiwa' era (2019-05-01 - )
155 * which has the value 3. The end date of this era is not specified, unless
156 * the Japanese Government defines it.
157 *
158 * @since 13
159 */
160 public static final JapaneseEra REIWA = new JapaneseEra(3, LocalDate.of(2019, 5, 1));
161
162 // The number of predefined JapaneseEra constants.
163 // There may be a supplemental era defined by the property.
164 private static final int N_ERA_CONSTANTS = REIWA.getValue() + ERA_OFFSET;
165
166 /**
167 * Serialization version.
168 */
169 @java.io.Serial
170 private static final long serialVersionUID = 1466499369062886794L;
171
172 // array for the singleton JapaneseEra instances
173 private static final JapaneseEra[] KNOWN_ERAS;
174
175 static {
176 ERA_CONFIG = JapaneseChronology.JCAL.getEras();
177
178 KNOWN_ERAS = new JapaneseEra[ERA_CONFIG.length];
179 KNOWN_ERAS[0] = MEIJI;
180 KNOWN_ERAS[1] = TAISHO;
181 KNOWN_ERAS[2] = SHOWA;
182 KNOWN_ERAS[3] = HEISEI;
183 KNOWN_ERAS[4] = REIWA;
184 for (int i = N_ERA_CONSTANTS; i < ERA_CONFIG.length; i++) {
185 CalendarDate date = ERA_CONFIG[i].getSinceDate();
186 LocalDate isoDate = LocalDate.of(date.getYear(), date.getMonth(), date.getDayOfMonth());
187 KNOWN_ERAS[i] = new JapaneseEra(i - ERA_OFFSET + 1, isoDate);
188 }
189 };
190
191 /**
192 * The era value.
193 * @serial
194 */
195 private final transient int eraValue;
196
197 // the first day of the era
198 private final transient LocalDate since;
199
200 /**
201 * Creates an instance.
202 *
203 * @param eraValue the era value, validated
204 * @param since the date representing the first date of the era, validated not null
205 */
206 private JapaneseEra(int eraValue, LocalDate since) {
207 this.eraValue = eraValue;
208 this.since = since;
209 }
210
211 //-----------------------------------------------------------------------
212 /**
213 * Returns the Sun private Era instance corresponding to this {@code JapaneseEra}.
214 *
215 * @return the Sun private Era instance for this {@code JapaneseEra}.
216 */
217 sun.util.calendar.Era getPrivateEra() {
218 return ERA_CONFIG[ordinal(eraValue)];
219 }
220
221 //-----------------------------------------------------------------------
222 /**
223 * Obtains an instance of {@code JapaneseEra} from an {@code int} value.
224 * <ul>
225 * <li>The value {@code 1} is associated with the 'Showa' era, because
226 * it contains 1970-01-01 (ISO calendar system).</li>
227 * <li>The values {@code -1} and {@code 0} are associated with two earlier
228 * eras, Meiji and Taisho, respectively.</li>
229 * <li>A value greater than {@code 1} is associated with a later era,
230 * beginning with Heisei ({@code 2}).</li>
231 * </ul>
232 * <p>
233 * Every instance of {@code JapaneseEra} that is returned from the {@link #values()}
234 * method has an int value (available via {@link Era#getValue()} which is
235 * accepted by this method.
236 *
237 * @param japaneseEra the era to represent
238 * @return the {@code JapaneseEra} singleton, not null
239 * @throws DateTimeException if the value is invalid
240 */
241 public static JapaneseEra of(int japaneseEra) {
242 int i = ordinal(japaneseEra);
243 if (i < 0 || i >= KNOWN_ERAS.length) {
244 throw new DateTimeException("Invalid era: " + japaneseEra);
245 }
246 return KNOWN_ERAS[i];
247 }
248
249 /**
250 * Returns the {@code JapaneseEra} with the name.
251 * <p>
252 * The string must match exactly the name of the era.
253 * (Extraneous whitespace characters are not permitted.)
254 * <p>
255 * Valid era names are the names of eras returned from {@link #values()}.
256 *
257 * @param japaneseEra the japaneseEra name; non-null
258 * @return the {@code JapaneseEra} singleton, never null
259 * @throws IllegalArgumentException if there is not JapaneseEra with the specified name
260 */
261 public static JapaneseEra valueOf(String japaneseEra) {
262 Objects.requireNonNull(japaneseEra, "japaneseEra");
263 for (JapaneseEra era : KNOWN_ERAS) {
264 if (era.getName().equals(japaneseEra)) {
265 return era;
266 }
267 }
268 throw new IllegalArgumentException("japaneseEra is invalid");
269 }
270
271 /**
272 * Returns an array of JapaneseEras. The array may contain eras defined
273 * by the Japanese government beyond the known era singletons.
274 *
275 * <p>
276 * This method may be used to iterate over the JapaneseEras as follows:
277 * <pre>
278 * for (JapaneseEra c : JapaneseEra.values())
279 * System.out.println(c);
280 * </pre>
281 *
282 * @return an array of JapaneseEras
283 */
284 public static JapaneseEra[] values() {
285 return Arrays.copyOf(KNOWN_ERAS, KNOWN_ERAS.length);
286 }
287
288 /**
289 * {@inheritDoc}
290 *
291 * @param style {@inheritDoc}
292 * @param locale {@inheritDoc}
293 */
294 @Override
295 public String getDisplayName(TextStyle style, Locale locale) {
296 // If this JapaneseEra is a supplemental one, obtain the name from
297 // the era definition.
298 if (getValue() > N_ERA_CONSTANTS - ERA_OFFSET) {
299 Objects.requireNonNull(locale, "locale");
300 return style.asNormal() == TextStyle.NARROW ? getAbbreviation() : getName();
301 }
302
303 return new DateTimeFormatterBuilder()
304 .appendText(ERA, style)
305 .toFormatter(locale)
306 .withChronology(JapaneseChronology.INSTANCE)
307 .format(this == MEIJI ? MEIJI_6_ISODATE : since);
308 }
309
310 //-----------------------------------------------------------------------
311 /**
312 * Obtains an instance of {@code JapaneseEra} from a date.
313 *
314 * @param date the date, not null
315 * @return the Era singleton, never null
316 */
317 static JapaneseEra from(LocalDate date) {
318 if (date.isBefore(MEIJI_6_ISODATE)) {
319 throw new DateTimeException("JapaneseDate before Meiji 6 are not supported");
320 }
321 for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
322 JapaneseEra era = KNOWN_ERAS[i];
323 if (date.compareTo(era.since) >= 0) {
324 return era;
325 }
326 }
327 return null;
328 }
329
330 static JapaneseEra toJapaneseEra(sun.util.calendar.Era privateEra) {
331 for (int i = ERA_CONFIG.length - 1; i >= 0; i--) {
332 if (ERA_CONFIG[i].equals(privateEra)) {
333 return KNOWN_ERAS[i];
334 }
335 }
336 return null;
337 }
338
339 static sun.util.calendar.Era privateEraFrom(LocalDate isoDate) {
340 for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
341 JapaneseEra era = KNOWN_ERAS[i];
342 if (isoDate.compareTo(era.since) >= 0) {
343 return ERA_CONFIG[i];
344 }
345 }
346 return null;
347 }
348
349 /**
350 * Returns the index into the arrays from the Era value.
351 * the eraValue is a valid Era number, -1..2.
352 *
353 * @param eraValue the era value to convert to the index
354 * @return the index of the current Era
355 */
356 private static int ordinal(int eraValue) {
357 return eraValue + ERA_OFFSET - 1;
358 }
359
360 //-----------------------------------------------------------------------
361 /**
362 * Gets the numeric era {@code int} value.
363 * <p>
364 * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
365 * Later eras are numbered from 2 ({@link #HEISEI}).
366 * Earlier eras are numbered 0 ({@link #TAISHO}), -1 ({@link #MEIJI})).
367 *
368 * @return the era value
369 */
370 @Override
371 public int getValue() {
372 return eraValue;
373 }
374
375 //-----------------------------------------------------------------------
376 /**
377 * Gets the range of valid values for the specified field.
378 * <p>
379 * The range object expresses the minimum and maximum valid values for a field.
380 * This era is used to enhance the accuracy of the returned range.
381 * If it is not possible to return the range, because the field is not supported
382 * or for some other reason, an exception is thrown.
383 * <p>
384 * If the field is a {@link ChronoField} then the query is implemented here.
385 * The {@code ERA} field returns the range.
386 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
387 * <p>
388 * If the field is not a {@code ChronoField}, then the result of this method
389 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
390 * passing {@code this} as the argument.
391 * Whether the range can be obtained is determined by the field.
392 * <p>
393 * The range of valid Japanese eras can change over time due to the nature
394 * of the Japanese calendar system.
395 *
396 * @param field the field to query the range for, not null
397 * @return the range of valid values for the field, not null
398 * @throws DateTimeException if the range for the field cannot be obtained
399 * @throws UnsupportedTemporalTypeException if the unit is not supported
400 */
401 @Override // override as super would return range from 0 to 1
402 public ValueRange range(TemporalField field) {
403 if (field == ERA) {
404 return JapaneseChronology.INSTANCE.range(ERA);
405 }
406 return Era.super.range(field);
407 }
408
409 //-----------------------------------------------------------------------
410 String getAbbreviation() {
411 return ERA_CONFIG[ordinal(getValue())].getAbbreviation();
412 }
413
414 String getName() {
415 return ERA_CONFIG[ordinal(getValue())].getName();
416 }
417
418 @Override
419 public String toString() {
420 return getName();
421 }
422
423 //-----------------------------------------------------------------------
424 /**
425 * Defend against malicious streams.
426 *
427 * @param s the stream to read
428 * @throws InvalidObjectException always
429 */
430 @java.io.Serial
431 private void readObject(ObjectInputStream s) throws InvalidObjectException {
432 throw new InvalidObjectException("Deserialization via serialization delegate");
433 }
434
435 //-----------------------------------------------------------------------
436 /**
437 * Writes the object using a
438 * <a href="{@docRoot}/serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
439 * @serialData
440 * <pre>
441 * out.writeByte(5); // identifies a JapaneseEra
442 * out.writeInt(getValue());
443 * </pre>
444 *
445 * @return the instance of {@code Ser}, not null
446 */
447 @java.io.Serial
448 private Object writeReplace() {
449 return new Ser(Ser.JAPANESE_ERA_TYPE, this);
450 }
451
452 void writeExternal(DataOutput out) throws IOException {
453 out.writeByte(this.getValue());
454 }
455
456 static JapaneseEra readExternal(DataInput in) throws IOException {
457 byte eraValue = in.readByte();
458 return JapaneseEra.of(eraValue);
459 }
460
461 }