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 JapaneseEra for each
100 * era. The {@link #values()} method returns the singleton instances of all
101 * 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 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 number of predefined JapaneseEra constants.
155 // There may be a supplemental era defined by the property.
156 private static final int N_ERA_CONSTANTS = HEISEI.getValue() + ERA_OFFSET;
157
158 /**
159 * Serialization version.
160 */
161 private static final long serialVersionUID = 1466499369062886794L;
162
163 // array for the singleton JapaneseEra instances
164 private static final JapaneseEra[] KNOWN_ERAS;
165
166 static {
167 ERA_CONFIG = JapaneseChronology.JCAL.getEras();
168
169 KNOWN_ERAS = new JapaneseEra[ERA_CONFIG.length];
170 KNOWN_ERAS[0] = MEIJI;
171 KNOWN_ERAS[1] = TAISHO;
172 KNOWN_ERAS[2] = SHOWA;
173 KNOWN_ERAS[3] = HEISEI;
174 for (int i = N_ERA_CONSTANTS; i < ERA_CONFIG.length; i++) {
175 CalendarDate date = ERA_CONFIG[i].getSinceDate();
176 LocalDate isoDate = LocalDate.of(date.getYear(), date.getMonth(), date.getDayOfMonth());
177 KNOWN_ERAS[i] = new JapaneseEra(i - ERA_OFFSET + 1, isoDate);
178 }
179 };
180
181 /**
182 * The era value.
183 * @serial
184 */
185 private final transient int eraValue;
186
187 // the first day of the era
188 private final transient LocalDate since;
189
190 /**
191 * Creates an instance.
192 *
193 * @param eraValue the era value, validated
194 * @param since the date representing the first date of the era, validated not null
195 */
196 private JapaneseEra(int eraValue, LocalDate since) {
197 this.eraValue = eraValue;
198 this.since = since;
199 }
200
201 //-----------------------------------------------------------------------
202 /**
203 * Returns the Sun private Era instance corresponding to this {@code JapaneseEra}.
204 *
205 * @return the Sun private Era instance for this {@code JapaneseEra}.
206 */
207 sun.util.calendar.Era getPrivateEra() {
208 return ERA_CONFIG[ordinal(eraValue)];
209 }
210
211 //-----------------------------------------------------------------------
212 /**
213 * Obtains an instance of {@code JapaneseEra} from an {@code int} value.
214 * <ul>
215 * <li>The value {@code 1} is associated with the 'Showa' era, because
216 * it contains 1970-01-01 (ISO calendar system).</li>
217 * <li>The values {@code -1} and {@code 0} are associated with two earlier
218 * eras, Meiji and Taisho, respectively.</li>
219 * <li>A value greater than {@code 1} is associated with a later era,
220 * beginning with Heisei ({@code 2}).</li>
221 * </ul>
222 * <p>
223 * Every instance of {@code JapaneseEra} that is returned from the {@link values()}
224 * method has an int value (available via {@link Era#getValue()} which is
225 * accepted by this method.
226 *
227 * @param japaneseEra the era to represent
228 * @return the {@code JapaneseEra} singleton, not null
229 * @throws DateTimeException if the value is invalid
230 */
231 public static JapaneseEra of(int japaneseEra) {
232 if (japaneseEra < MEIJI.eraValue || japaneseEra + ERA_OFFSET > KNOWN_ERAS.length) {
233 throw new DateTimeException("Invalid era: " + japaneseEra);
234 }
235 return KNOWN_ERAS[ordinal(japaneseEra)];
236 }
237
238 /**
239 * Returns the {@code JapaneseEra} with the name.
240 * <p>
241 * The string must match exactly the name of the era.
242 * (Extraneous whitespace characters are not permitted.)
243 *
244 * @param japaneseEra the japaneseEra name; non-null
245 * @return the {@code JapaneseEra} singleton, never null
246 * @throws IllegalArgumentException if there is not JapaneseEra with the specified name
247 */
248 public static JapaneseEra valueOf(String japaneseEra) {
249 Objects.requireNonNull(japaneseEra, "japaneseEra");
250 for (JapaneseEra era : KNOWN_ERAS) {
251 if (era.getName().equals(japaneseEra)) {
252 return era;
253 }
254 }
255 throw new IllegalArgumentException("japaneseEra is invalid");
256 }
257
258 /**
259 * Returns an array of JapaneseEras.
260 * <p>
261 * This method may be used to iterate over the JapaneseEras as follows:
262 * <pre>
263 * for (JapaneseEra c : JapaneseEra.values())
264 * System.out.println(c);
265 * </pre>
266 *
267 * @return an array of JapaneseEras
268 */
269 public static JapaneseEra[] values() {
270 return Arrays.copyOf(KNOWN_ERAS, KNOWN_ERAS.length);
271 }
272
273 /**
274 * {@inheritDoc}
275 *
276 * @param style {@inheritDoc}
277 * @param locale {@inheritDoc}
278 */
279 @Override
280 public String getDisplayName(TextStyle style, Locale locale) {
281 // If this JapaneseEra is a supplemental one, obtain the name from
282 // the era definition.
283 if (getValue() > N_ERA_CONSTANTS - ERA_OFFSET) {
284 Objects.requireNonNull(locale, "locale");
285 return style.asNormal() == TextStyle.NARROW ? getAbbreviation() : getName();
286 }
287
288 return new DateTimeFormatterBuilder()
289 .appendText(ERA, style)
290 .toFormatter(locale)
291 .withChronology(JapaneseChronology.INSTANCE)
292 .format(this == MEIJI ? MEIJI_6_ISODATE : since);
293 }
294
295 //-----------------------------------------------------------------------
296 /**
297 * Obtains an instance of {@code JapaneseEra} from a date.
298 *
299 * @param date the date, not null
300 * @return the Era singleton, never null
301 */
302 static JapaneseEra from(LocalDate date) {
303 if (date.isBefore(MEIJI_6_ISODATE)) {
304 throw new DateTimeException("JapaneseDate before Meiji 6 are not supported");
305 }
306 for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
307 JapaneseEra era = KNOWN_ERAS[i];
308 if (date.compareTo(era.since) >= 0) {
309 return era;
310 }
311 }
312 return null;
313 }
314
315 static JapaneseEra toJapaneseEra(sun.util.calendar.Era privateEra) {
316 for (int i = ERA_CONFIG.length - 1; i >= 0; i--) {
317 if (ERA_CONFIG[i].equals(privateEra)) {
318 return KNOWN_ERAS[i];
319 }
320 }
321 return null;
322 }
323
324 static sun.util.calendar.Era privateEraFrom(LocalDate isoDate) {
325 for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
326 JapaneseEra era = KNOWN_ERAS[i];
327 if (isoDate.compareTo(era.since) >= 0) {
328 return ERA_CONFIG[i];
329 }
330 }
331 return null;
332 }
333
334 /**
335 * Returns the index into the arrays from the Era value.
336 * the eraValue is a valid Era number, -1..2.
337 *
338 * @param eraValue the era value to convert to the index
339 * @return the index of the current Era
340 */
341 private static int ordinal(int eraValue) {
342 return eraValue + ERA_OFFSET - 1;
343 }
344
345 //-----------------------------------------------------------------------
346 /**
347 * Gets the numeric era {@code int} value.
348 * <p>
349 * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
350 * Later eras are numbered from 2 ({@link #HEISEI}).
351 * Earlier eras are numbered 0 ({@link #TAISHO}), -1 ({@link #MEIJI})).
352 *
353 * @return the era value
354 */
355 @Override
356 public int getValue() {
357 return eraValue;
358 }
359
360 //-----------------------------------------------------------------------
361 /**
362 * Gets the range of valid values for the specified field.
363 * <p>
364 * The range object expresses the minimum and maximum valid values for a field.
365 * This era is used to enhance the accuracy of the returned range.
366 * If it is not possible to return the range, because the field is not supported
367 * or for some other reason, an exception is thrown.
368 * <p>
369 * If the field is a {@link ChronoField} then the query is implemented here.
370 * The {@code ERA} field returns the range.
371 * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
372 * <p>
373 * If the field is not a {@code ChronoField}, then the result of this method
374 * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
375 * passing {@code this} as the argument.
376 * Whether the range can be obtained is determined by the field.
377 * <p>
378 * The range of valid Japanese eras can change over time due to the nature
379 * of the Japanese calendar system.
380 *
381 * @param field the field to query the range for, not null
382 * @return the range of valid values for the field, not null
383 * @throws DateTimeException if the range for the field cannot be obtained
384 * @throws UnsupportedTemporalTypeException if the unit is not supported
385 */
386 @Override // override as super would return range from 0 to 1
387 public ValueRange range(TemporalField field) {
388 if (field == ERA) {
389 return JapaneseChronology.INSTANCE.range(ERA);
390 }
391 return Era.super.range(field);
392 }
393
394 //-----------------------------------------------------------------------
395 String getAbbreviation() {
396 return ERA_CONFIG[ordinal(getValue())].getAbbreviation();
397 }
398
399 String getName() {
400 return ERA_CONFIG[ordinal(getValue())].getName();
401 }
402
403 @Override
404 public String toString() {
405 return getName();
406 }
407
408 //-----------------------------------------------------------------------
409 /**
410 * Defend against malicious streams.
411 *
412 * @param s the stream to read
413 * @throws InvalidObjectException always
414 */
415 private void readObject(ObjectInputStream s) throws InvalidObjectException {
416 throw new InvalidObjectException("Deserialization via serialization delegate");
417 }
418
419 //-----------------------------------------------------------------------
420 /**
421 * Writes the object using a
422 * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
423 * @serialData
424 * <pre>
425 * out.writeByte(5); // identifies a JapaneseEra
426 * out.writeInt(getValue());
427 * </pre>
428 *
429 * @return the instance of {@code Ser}, not null
430 */
431 private Object writeReplace() {
432 return new Ser(Ser.JAPANESE_ERA_TYPE, this);
433 }
434
435 void writeExternal(DataOutput out) throws IOException {
436 out.writeByte(this.getValue());
437 }
438
439 static JapaneseEra readExternal(DataInput in) throws IOException {
440 byte eraValue = in.readByte();
441 return JapaneseEra.of(eraValue);
442 }
443
444 }