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26 /*
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31  *
32  * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos
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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.temporal.ChronoField;
77 import java.time.temporal.TemporalField;
78 import java.time.temporal.UnsupportedTemporalTypeException;
79 import java.time.temporal.ValueRange;
80 import java.util.Arrays;
81 import java.util.Objects;
82 
83 import sun.util.calendar.CalendarDate;
84 
85 /**
86  * An era in the Japanese Imperial calendar system.
87  * <p>
88  * This class defines the valid eras for the Japanese chronology.
89  * Japan introduced the Gregorian calendar starting with Meiji 6.
90  * Only Meiji and later eras are supported;
91  * dates before Meiji 6, January 1 are not supported.
92  *
93  * @implSpec
94  * This class is immutable and thread-safe.
95  *
96  * @since 1.8
97  */
98 public final class JapaneseEra
99         implements Era, Serializable {
100 
101     // The offset value to 0-based index from the era value.
102     // i.e., getValue() + ERA_OFFSET == 0-based index
103     static final int ERA_OFFSET = 2;
104 
105     static final sun.util.calendar.Era[] ERA_CONFIG;
106 
107     /**
108      * The singleton instance for the 'Meiji' era (1868-01-01 - 1912-07-29)
109      * which has the value -1.
110      */
111     public static final JapaneseEra MEIJI = new JapaneseEra(-1, LocalDate.of(1868, 1, 1));
112     /**
113      * The singleton instance for the 'Taisho' era (1912-07-30 - 1926-12-24)
114      * which has the value 0.
115      */
116     public static final JapaneseEra TAISHO = new JapaneseEra(0, LocalDate.of(1912, 7, 30));
117     /**
118      * The singleton instance for the 'Showa' era (1926-12-25 - 1989-01-07)
119      * which has the value 1.
120      */
121     public static final JapaneseEra SHOWA = new JapaneseEra(1, LocalDate.of(1926, 12, 25));
122     /**
123      * The singleton instance for the 'Heisei' era (1989-01-08 - current)
124      * which has the value 2.
125      */
126     public static final JapaneseEra HEISEI = new JapaneseEra(2, LocalDate.of(1989, 1, 8));
127 
128     // the number of defined JapaneseEra constants.
129     // There could be an extra era defined in its configuration.
130     private static final int N_ERA_CONSTANTS = HEISEI.getValue() + ERA_OFFSET;
131 
132     /**
133      * Serialization version.
134      */
135     private static final long serialVersionUID = 1466499369062886794L;
136 
137     // array for the singleton JapaneseEra instances
138     private static final JapaneseEra[] KNOWN_ERAS;
139 
140     static {
141         ERA_CONFIG = JapaneseChronology.JCAL.getEras();
142 
143         KNOWN_ERAS = new JapaneseEra[ERA_CONFIG.length];
144         KNOWN_ERAS[0] = MEIJI;
145         KNOWN_ERAS[1] = TAISHO;
146         KNOWN_ERAS[2] = SHOWA;
147         KNOWN_ERAS[3] = HEISEI;
148         for (int i = N_ERA_CONSTANTS; i < ERA_CONFIG.length; i++) {
149             CalendarDate date = ERA_CONFIG[i].getSinceDate();
150             LocalDate isoDate = LocalDate.of(date.getYear(), date.getMonth(), date.getDayOfMonth());
151             KNOWN_ERAS[i] = new JapaneseEra(i - ERA_OFFSET + 1, isoDate);
152         }
153     };
154 
155     /**
156      * The era value.
157      * @serial
158      */
159     private final transient int eraValue;
160 
161     // the first day of the era
162     private final transient LocalDate since;
163 
164     /**
165      * Creates an instance.
166      *
167      * @param eraValue  the era value, validated
168      * @param since  the date representing the first date of the era, validated not null
169      */
JapaneseEra(int eraValue, LocalDate since)170     private JapaneseEra(int eraValue, LocalDate since) {
171         this.eraValue = eraValue;
172         this.since = since;
173     }
174 
175     //-----------------------------------------------------------------------
176     /**
177      * Returns the Sun private Era instance corresponding to this {@code JapaneseEra}.
178      *
179      * @return the Sun private Era instance for this {@code JapaneseEra}.
180      */
getPrivateEra()181     sun.util.calendar.Era getPrivateEra() {
182         return ERA_CONFIG[ordinal(eraValue)];
183     }
184 
185     //-----------------------------------------------------------------------
186     /**
187      * Obtains an instance of {@code JapaneseEra} from an {@code int} value.
188      * <p>
189      * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1
190      * Later era is numbered 2 ({@link #HEISEI}). Earlier eras are numbered 0 ({@link #TAISHO}),
191      * -1 ({@link #MEIJI}), only Meiji and later eras are supported.
192      *
193      * @param japaneseEra  the era to represent
194      * @return the {@code JapaneseEra} singleton, not null
195      * @throws DateTimeException if the value is invalid
196      */
of(int japaneseEra)197     public static JapaneseEra of(int japaneseEra) {
198         if (japaneseEra < MEIJI.eraValue || japaneseEra + ERA_OFFSET > KNOWN_ERAS.length) {
199             throw new DateTimeException("Invalid era: " + japaneseEra);
200         }
201         return KNOWN_ERAS[ordinal(japaneseEra)];
202     }
203 
204     /**
205      * Returns the {@code JapaneseEra} with the name.
206      * <p>
207      * The string must match exactly the name of the era.
208      * (Extraneous whitespace characters are not permitted.)
209      *
210      * @param japaneseEra  the japaneseEra name; non-null
211      * @return the {@code JapaneseEra} singleton, never null
212      * @throws IllegalArgumentException if there is not JapaneseEra with the specified name
213      */
valueOf(String japaneseEra)214     public static JapaneseEra valueOf(String japaneseEra) {
215         Objects.requireNonNull(japaneseEra, "japaneseEra");
216         for (JapaneseEra era : KNOWN_ERAS) {
217             if (era.getName().equals(japaneseEra)) {
218                 return era;
219             }
220         }
221         throw new IllegalArgumentException("japaneseEra is invalid");
222     }
223 
224     /**
225      * Returns an array of JapaneseEras.
226      * <p>
227      * This method may be used to iterate over the JapaneseEras as follows:
228      * <pre>
229      * for (JapaneseEra c : JapaneseEra.values())
230      *     System.out.println(c);
231      * </pre>
232      *
233      * @return an array of JapaneseEras
234      */
values()235     public static JapaneseEra[] values() {
236         return Arrays.copyOf(KNOWN_ERAS, KNOWN_ERAS.length);
237     }
238 
239     //-----------------------------------------------------------------------
240     /**
241      * Obtains an instance of {@code JapaneseEra} from a date.
242      *
243      * @param date  the date, not null
244      * @return the Era singleton, never null
245      */
from(LocalDate date)246     static JapaneseEra from(LocalDate date) {
247         if (date.isBefore(MEIJI_6_ISODATE)) {
248             throw new DateTimeException("JapaneseDate before Meiji 6 are not supported");
249         }
250         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
251             JapaneseEra era = KNOWN_ERAS[i];
252             if (date.compareTo(era.since) >= 0) {
253                 return era;
254             }
255         }
256         return null;
257     }
258 
toJapaneseEra(sun.util.calendar.Era privateEra)259     static JapaneseEra toJapaneseEra(sun.util.calendar.Era privateEra) {
260         for (int i = ERA_CONFIG.length - 1; i >= 0; i--) {
261             if (ERA_CONFIG[i].equals(privateEra)) {
262                 return KNOWN_ERAS[i];
263             }
264         }
265         return null;
266     }
267 
privateEraFrom(LocalDate isoDate)268     static sun.util.calendar.Era privateEraFrom(LocalDate isoDate) {
269         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
270             JapaneseEra era = KNOWN_ERAS[i];
271             if (isoDate.compareTo(era.since) >= 0) {
272                 return ERA_CONFIG[i];
273             }
274         }
275         return null;
276     }
277 
278     /**
279      * Returns the index into the arrays from the Era value.
280      * the eraValue is a valid Era number, -1..2.
281      *
282      * @param eraValue  the era value to convert to the index
283      * @return the index of the current Era
284      */
ordinal(int eraValue)285     private static int ordinal(int eraValue) {
286         return eraValue + ERA_OFFSET - 1;
287     }
288 
289     //-----------------------------------------------------------------------
290     /**
291      * Gets the numeric era {@code int} value.
292      * <p>
293      * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
294      * Later eras are numbered from 2 ({@link #HEISEI}).
295      * Earlier eras are numbered 0 ({@link #TAISHO}), -1 ({@link #MEIJI})).
296      *
297      * @return the era value
298      */
299     @Override
getValue()300     public int getValue() {
301         return eraValue;
302     }
303 
304     //-----------------------------------------------------------------------
305     /**
306      * Gets the range of valid values for the specified field.
307      * <p>
308      * The range object expresses the minimum and maximum valid values for a field.
309      * This era is used to enhance the accuracy of the returned range.
310      * If it is not possible to return the range, because the field is not supported
311      * or for some other reason, an exception is thrown.
312      * <p>
313      * If the field is a {@link ChronoField} then the query is implemented here.
314      * The {@code ERA} field returns the range.
315      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
316      * <p>
317      * If the field is not a {@code ChronoField}, then the result of this method
318      * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
319      * passing {@code this} as the argument.
320      * Whether the range can be obtained is determined by the field.
321      * <p>
322      * The range of valid Japanese eras can change over time due to the nature
323      * of the Japanese calendar system.
324      *
325      * @param field  the field to query the range for, not null
326      * @return the range of valid values for the field, not null
327      * @throws DateTimeException if the range for the field cannot be obtained
328      * @throws UnsupportedTemporalTypeException if the unit is not supported
329      */
330     @Override  // override as super would return range from 0 to 1
range(TemporalField field)331     public ValueRange range(TemporalField field) {
332         if (field == ERA) {
333             return JapaneseChronology.INSTANCE.range(ERA);
334         }
335         return Era.super.range(field);
336     }
337 
338     //-----------------------------------------------------------------------
getAbbreviation()339     String getAbbreviation() {
340         int index = ordinal(getValue());
341         if (index == 0) {
342             return "";
343         }
344         return ERA_CONFIG[index].getAbbreviation();
345     }
346 
getName()347     String getName() {
348         return ERA_CONFIG[ordinal(getValue())].getName();
349     }
350 
351     @Override
toString()352     public String toString() {
353         return getName();
354     }
355 
356     //-----------------------------------------------------------------------
357     /**
358      * Defend against malicious streams.
359      *
360      * @param s the stream to read
361      * @throws InvalidObjectException always
362      */
readObject(ObjectInputStream s)363     private void readObject(ObjectInputStream s) throws InvalidObjectException {
364         throw new InvalidObjectException("Deserialization via serialization delegate");
365     }
366 
367     //-----------------------------------------------------------------------
368     /**
369      * Writes the object using a
370      * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
371      * @serialData
372      * <pre>
373      *  out.writeByte(5);        // identifies a JapaneseEra
374      *  out.writeInt(getValue());
375      * </pre>
376      *
377      * @return the instance of {@code Ser}, not null
378      */
writeReplace()379     private Object writeReplace() {
380         return new Ser(Ser.JAPANESE_ERA_TYPE, this);
381     }
382 
writeExternal(DataOutput out)383     void writeExternal(DataOutput out) throws IOException {
384         out.writeByte(this.getValue());
385     }
386 
readExternal(DataInput in)387     static JapaneseEra readExternal(DataInput in) throws IOException {
388         byte eraValue = in.readByte();
389         return JapaneseEra.of(eraValue);
390     }
391 
392 }
393