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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     // Android-changed: Integrate OpenJDK support for Japanese Era Reiwa.
154     /**
155      * The singleton instance for the 'Reiwa' era (2019-05-01 - current)
156      * which has the value 3. The end date of this era is not specified, unless
157      * the Japanese Government defines it.
158      */
159     public static final JapaneseEra REIWA = new JapaneseEra(3, LocalDate.of(2019, 5, 1));
160 
161     // The number of predefined JapaneseEra constants.
162     // There may be a supplemental era defined by the property.
163     private static final int N_ERA_CONSTANTS = REIWA.getValue() + ERA_OFFSET;
164 
165     /**
166      * Serialization version.
167      */
168     private static final long serialVersionUID = 1466499369062886794L;
169 
170     // array for the singleton JapaneseEra instances
171     private static final JapaneseEra[] KNOWN_ERAS;
172 
173     static {
174         ERA_CONFIG = JapaneseChronology.JCAL.getEras();
175 
176         KNOWN_ERAS = new JapaneseEra[ERA_CONFIG.length];
177         KNOWN_ERAS[0] = MEIJI;
178         KNOWN_ERAS[1] = TAISHO;
179         KNOWN_ERAS[2] = SHOWA;
180         KNOWN_ERAS[3] = HEISEI;
181         KNOWN_ERAS[4] = REIWA;
182         for (int i = N_ERA_CONSTANTS; i < ERA_CONFIG.length; i++) {
183             CalendarDate date = ERA_CONFIG[i].getSinceDate();
184             LocalDate isoDate = LocalDate.of(date.getYear(), date.getMonth(), date.getDayOfMonth());
185             KNOWN_ERAS[i] = new JapaneseEra(i - ERA_OFFSET + 1, isoDate);
186         }
187     };
188 
189     /**
190      * The era value.
191      * @serial
192      */
193     private final transient int eraValue;
194 
195     // the first day of the era
196     private final transient LocalDate since;
197 
198     /**
199      * Creates an instance.
200      *
201      * @param eraValue  the era value, validated
202      * @param since  the date representing the first date of the era, validated not null
203      */
JapaneseEra(int eraValue, LocalDate since)204     private JapaneseEra(int eraValue, LocalDate since) {
205         this.eraValue = eraValue;
206         this.since = since;
207     }
208 
209     //-----------------------------------------------------------------------
210     /**
211      * Returns the Sun private Era instance corresponding to this {@code JapaneseEra}.
212      *
213      * @return the Sun private Era instance for this {@code JapaneseEra}.
214      */
getPrivateEra()215     sun.util.calendar.Era getPrivateEra() {
216         return ERA_CONFIG[ordinal(eraValue)];
217     }
218 
219     //-----------------------------------------------------------------------
220     /**
221      * Obtains an instance of {@code JapaneseEra} from an {@code int} value.
222       * <ul>
223       * <li>The value {@code 1} is associated with the 'Showa' era, because
224       * it contains 1970-01-01 (ISO calendar system).</li>
225       * <li>The values {@code -1} and {@code 0} are associated with two earlier
226       * eras, Meiji and Taisho, respectively.</li>
227       * <li>A value greater than {@code 1} is associated with a later era,
228       * beginning with Heisei ({@code 2}).</li>
229       * </ul>
230      * <p>
231       * Every instance of {@code JapaneseEra} that is returned from the {@link #values()}
232       * method has an int value (available via {@link Era#getValue()} which is
233       * accepted by this method.
234      *
235      * @param japaneseEra  the era to represent
236      * @return the {@code JapaneseEra} singleton, not null
237      * @throws DateTimeException if the value is invalid
238      */
of(int japaneseEra)239     public static JapaneseEra of(int japaneseEra) {
240         if (japaneseEra < MEIJI.eraValue || japaneseEra + ERA_OFFSET > KNOWN_ERAS.length) {
241             throw new DateTimeException("Invalid era: " + japaneseEra);
242         }
243         return KNOWN_ERAS[ordinal(japaneseEra)];
244     }
245 
246     /**
247      * Returns the {@code JapaneseEra} with the name.
248      * <p>
249      * The string must match exactly the name of the era.
250      * (Extraneous whitespace characters are not permitted.)
251      *
252      * @param japaneseEra  the japaneseEra name; non-null
253      * @return the {@code JapaneseEra} singleton, never null
254      * @throws IllegalArgumentException if there is not JapaneseEra with the specified name
255      */
valueOf(String japaneseEra)256     public static JapaneseEra valueOf(String japaneseEra) {
257         Objects.requireNonNull(japaneseEra, "japaneseEra");
258         for (JapaneseEra era : KNOWN_ERAS) {
259             if (era.getName().equals(japaneseEra)) {
260                 return era;
261             }
262         }
263         throw new IllegalArgumentException("japaneseEra is invalid");
264     }
265 
266     /**
267      * Returns an array of JapaneseEras.
268      * <p>
269      * This method may be used to iterate over the JapaneseEras as follows:
270      * <pre>
271      * for (JapaneseEra c : JapaneseEra.values())
272      *     System.out.println(c);
273      * </pre>
274      *
275      * @return an array of JapaneseEras
276      */
values()277     public static JapaneseEra[] values() {
278         return Arrays.copyOf(KNOWN_ERAS, KNOWN_ERAS.length);
279     }
280 
281     /**
282      * {@inheritDoc}
283      *
284      * @param style {@inheritDoc}
285      * @param locale {@inheritDoc}
286      */
287     @Override
getDisplayName(TextStyle style, Locale locale)288     public String getDisplayName(TextStyle style, Locale locale) {
289         // If this JapaneseEra is a supplemental one, obtain the name from
290         // the era definition.
291         if (getValue() > N_ERA_CONSTANTS - ERA_OFFSET) {
292             Objects.requireNonNull(locale, "locale");
293             return style.asNormal() == TextStyle.NARROW ? getAbbreviation() : getName();
294         }
295 
296         return new DateTimeFormatterBuilder()
297             .appendText(ERA, style)
298             .toFormatter(locale)
299             .withChronology(JapaneseChronology.INSTANCE)
300             .format(this == MEIJI ? MEIJI_6_ISODATE : since);
301     }
302 
303     //-----------------------------------------------------------------------
304     /**
305      * Obtains an instance of {@code JapaneseEra} from a date.
306      *
307      * @param date  the date, not null
308      * @return the Era singleton, never null
309      */
from(LocalDate date)310     static JapaneseEra from(LocalDate date) {
311         if (date.isBefore(MEIJI_6_ISODATE)) {
312             throw new DateTimeException("JapaneseDate before Meiji 6 are not supported");
313         }
314         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
315             JapaneseEra era = KNOWN_ERAS[i];
316             if (date.compareTo(era.since) >= 0) {
317                 return era;
318             }
319         }
320         return null;
321     }
322 
toJapaneseEra(sun.util.calendar.Era privateEra)323     static JapaneseEra toJapaneseEra(sun.util.calendar.Era privateEra) {
324         for (int i = ERA_CONFIG.length - 1; i >= 0; i--) {
325             if (ERA_CONFIG[i].equals(privateEra)) {
326                 return KNOWN_ERAS[i];
327             }
328         }
329         return null;
330     }
331 
privateEraFrom(LocalDate isoDate)332     static sun.util.calendar.Era privateEraFrom(LocalDate isoDate) {
333         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
334             JapaneseEra era = KNOWN_ERAS[i];
335             if (isoDate.compareTo(era.since) >= 0) {
336                 return ERA_CONFIG[i];
337             }
338         }
339         return null;
340     }
341 
342     /**
343      * Returns the index into the arrays from the Era value.
344      * the eraValue is a valid Era number, -1..2.
345      *
346      * @param eraValue  the era value to convert to the index
347      * @return the index of the current Era
348      */
ordinal(int eraValue)349     private static int ordinal(int eraValue) {
350         return eraValue + ERA_OFFSET - 1;
351     }
352 
353     //-----------------------------------------------------------------------
354     /**
355      * Gets the numeric era {@code int} value.
356      * <p>
357      * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
358      * Later eras are numbered from 2 ({@link #HEISEI}).
359      * Earlier eras are numbered 0 ({@link #TAISHO}), -1 ({@link #MEIJI})).
360      *
361      * @return the era value
362      */
363     @Override
getValue()364     public int getValue() {
365         return eraValue;
366     }
367 
368     //-----------------------------------------------------------------------
369     /**
370      * Gets the range of valid values for the specified field.
371      * <p>
372      * The range object expresses the minimum and maximum valid values for a field.
373      * This era is used to enhance the accuracy of the returned range.
374      * If it is not possible to return the range, because the field is not supported
375      * or for some other reason, an exception is thrown.
376      * <p>
377      * If the field is a {@link ChronoField} then the query is implemented here.
378      * The {@code ERA} field returns the range.
379      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
380      * <p>
381      * If the field is not a {@code ChronoField}, then the result of this method
382      * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
383      * passing {@code this} as the argument.
384      * Whether the range can be obtained is determined by the field.
385      * <p>
386      * The range of valid Japanese eras can change over time due to the nature
387      * of the Japanese calendar system.
388      *
389      * @param field  the field to query the range for, not null
390      * @return the range of valid values for the field, not null
391      * @throws DateTimeException if the range for the field cannot be obtained
392      * @throws UnsupportedTemporalTypeException if the unit is not supported
393      */
394     @Override  // override as super would return range from 0 to 1
range(TemporalField field)395     public ValueRange range(TemporalField field) {
396         if (field == ERA) {
397             return JapaneseChronology.INSTANCE.range(ERA);
398         }
399         return Era.super.range(field);
400     }
401 
402     //-----------------------------------------------------------------------
getAbbreviation()403     String getAbbreviation() {
404         return ERA_CONFIG[ordinal(getValue())].getAbbreviation();
405     }
406 
getName()407     String getName() {
408         return ERA_CONFIG[ordinal(getValue())].getName();
409     }
410 
411     @Override
toString()412     public String toString() {
413         return getName();
414     }
415 
416     //-----------------------------------------------------------------------
417     /**
418      * Defend against malicious streams.
419      *
420      * @param s the stream to read
421      * @throws InvalidObjectException always
422      */
readObject(ObjectInputStream s)423     private void readObject(ObjectInputStream s) throws InvalidObjectException {
424         throw new InvalidObjectException("Deserialization via serialization delegate");
425     }
426 
427     //-----------------------------------------------------------------------
428     /**
429      * Writes the object using a
430      * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
431      * @serialData
432      * <pre>
433      *  out.writeByte(5);        // identifies a JapaneseEra
434      *  out.writeInt(getValue());
435      * </pre>
436      *
437      * @return the instance of {@code Ser}, not null
438      */
writeReplace()439     private Object writeReplace() {
440         return new Ser(Ser.JAPANESE_ERA_TYPE, this);
441     }
442 
writeExternal(DataOutput out)443     void writeExternal(DataOutput out) throws IOException {
444         out.writeByte(this.getValue());
445     }
446 
readExternal(DataInput in)447     static JapaneseEra readExternal(DataInput in) throws IOException {
448         byte eraValue = in.readByte();
449         return JapaneseEra.of(eraValue);
450     }
451 
452 }
453