1 /*
   2  * Copyright (c) 2012, 2017, 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.TextStyle;
  77 import java.time.temporal.ChronoField;
  78 import java.time.temporal.TemporalField;
  79 import java.time.temporal.UnsupportedTemporalTypeException;
  80 import java.time.temporal.ValueRange;
  81 import java.util.Arrays;
  82 import java.util.Locale;
  83 import java.util.Objects;
  84 
  85 import sun.util.calendar.CalendarDate;
  86 
  87 /**
  88  * An era in the Japanese Imperial calendar system.
  89  * <p>
  90  * This class defines the valid eras for the Japanese chronology.
  91  * Japan introduced the Gregorian calendar starting with Meiji 6.
  92  * Only Meiji and later eras are supported;
  93  * dates before Meiji 6, January 1 are not supported.
  94  *
  95  * @implSpec
  96  * This class is immutable and thread-safe.
  97  *
  98  * @since 1.8
  99  */
 100 public final class JapaneseEra
 101         implements Era, Serializable {
 102 
 103     // The offset value to 0-based index from the era value.
 104     // i.e., getValue() + ERA_OFFSET == 0-based index
 105     static final int ERA_OFFSET = 2;
 106 
 107     static final sun.util.calendar.Era[] ERA_CONFIG;
 108 
 109     /**
 110      * The singleton instance for the 'Meiji' era (1868-01-01 - 1912-07-29)
 111      * which has the value -1.
 112      */
 113     public static final JapaneseEra MEIJI = new JapaneseEra(-1, LocalDate.of(1868, 1, 1));
 114     /**
 115      * The singleton instance for the 'Taisho' era (1912-07-30 - 1926-12-24)
 116      * which has the value 0.
 117      */
 118     public static final JapaneseEra TAISHO = new JapaneseEra(0, LocalDate.of(1912, 7, 30));
 119     /**
 120      * The singleton instance for the 'Showa' era (1926-12-25 - 1989-01-07)
 121      * which has the value 1.
 122      */
 123     public static final JapaneseEra SHOWA = new JapaneseEra(1, LocalDate.of(1926, 12, 25));
 124     /**
 125      * The singleton instance for the 'Heisei' era (1989-01-08 - current)
 126      * which has the value 2.
 127      */
 128     public static final JapaneseEra HEISEI = new JapaneseEra(2, LocalDate.of(1989, 1, 8));
 129 
 130     // The number of predefined JapaneseEra constants.
 131     // There may be a supplemental era defined by the property.
 132     private static final int N_ERA_CONSTANTS = HEISEI.getValue() + ERA_OFFSET;
 133 
 134     /**
 135      * Serialization version.
 136      */
 137     private static final long serialVersionUID = 1466499369062886794L;
 138 
 139     // array for the singleton JapaneseEra instances
 140     private static final JapaneseEra[] KNOWN_ERAS;
 141 
 142     static {
 143         ERA_CONFIG = JapaneseChronology.JCAL.getEras();
 144 
 145         KNOWN_ERAS = new JapaneseEra[ERA_CONFIG.length];
 146         KNOWN_ERAS[0] = MEIJI;
 147         KNOWN_ERAS[1] = TAISHO;
 148         KNOWN_ERAS[2] = SHOWA;
 149         KNOWN_ERAS[3] = HEISEI;
 150         for (int i = N_ERA_CONSTANTS; i < ERA_CONFIG.length; i++) {
 151             CalendarDate date = ERA_CONFIG[i].getSinceDate();
 152             LocalDate isoDate = LocalDate.of(date.getYear(), date.getMonth(), date.getDayOfMonth());
 153             KNOWN_ERAS[i] = new JapaneseEra(i - ERA_OFFSET + 1, isoDate);
 154         }
 155     };
 156 
 157     /**
 158      * The era value.
 159      * @serial
 160      */
 161     private final transient int eraValue;
 162 
 163     // the first day of the era
 164     private final transient LocalDate since;
 165 
 166     /**
 167      * Creates an instance.
 168      *
 169      * @param eraValue  the era value, validated
 170      * @param since  the date representing the first date of the era, validated not null
 171      */
 172     private JapaneseEra(int eraValue, LocalDate since) {
 173         this.eraValue = eraValue;
 174         this.since = since;
 175     }
 176 
 177     //-----------------------------------------------------------------------
 178     /**
 179      * Returns the Sun private Era instance corresponding to this {@code JapaneseEra}.
 180      *
 181      * @return the Sun private Era instance for this {@code JapaneseEra}.
 182      */
 183     sun.util.calendar.Era getPrivateEra() {
 184         return ERA_CONFIG[ordinal(eraValue)];
 185     }
 186 
 187     //-----------------------------------------------------------------------
 188     /**
 189      * Obtains an instance of {@code JapaneseEra} from an {@code int} value.
 190      * <p>
 191      * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1
 192      * Later era is numbered 2 ({@link #HEISEI}). Earlier eras are numbered 0 ({@link #TAISHO}),
 193      * -1 ({@link #MEIJI}), only Meiji and later eras are supported.
 194      *
 195      * @param japaneseEra  the era to represent
 196      * @return the {@code JapaneseEra} singleton, not null
 197      * @throws DateTimeException if the value is invalid
 198      */
 199     public static JapaneseEra of(int japaneseEra) {
 200         int i = ordinal(japaneseEra);
 201         if (i < 0 || i >= KNOWN_ERAS.length) {
 202             throw new DateTimeException("Invalid era: " + japaneseEra);
 203         }
 204         return KNOWN_ERAS[i];
 205     }
 206 
 207     /**
 208      * Returns the {@code JapaneseEra} with the name.
 209      * <p>
 210      * The string must match exactly the name of the era.
 211      * (Extraneous whitespace characters are not permitted.)
 212      *
 213      * @param japaneseEra  the japaneseEra name; non-null
 214      * @return the {@code JapaneseEra} singleton, never null
 215      * @throws IllegalArgumentException if there is not JapaneseEra with the specified name
 216      */
 217     public static JapaneseEra valueOf(String japaneseEra) {
 218         Objects.requireNonNull(japaneseEra, "japaneseEra");
 219         for (JapaneseEra era : KNOWN_ERAS) {
 220             if (era.getName().equals(japaneseEra)) {
 221                 return era;
 222             }
 223         }
 224         throw new IllegalArgumentException("japaneseEra is invalid");
 225     }
 226 
 227     /**
 228      * Returns an array of JapaneseEras.
 229      * <p>
 230      * This method may be used to iterate over the JapaneseEras as follows:
 231      * <pre>
 232      * for (JapaneseEra c : JapaneseEra.values())
 233      *     System.out.println(c);
 234      * </pre>
 235      *
 236      * @return an array of JapaneseEras
 237      */
 238     public static JapaneseEra[] values() {
 239         return Arrays.copyOf(KNOWN_ERAS, KNOWN_ERAS.length);
 240     }
 241 
 242     /**
 243      * {@inheritDoc}
 244      *
 245      * @param style {@inheritDoc}
 246      * @param locale {@inheritDoc}
 247      */
 248     @Override
 249     public String getDisplayName(TextStyle style, Locale locale) {
 250         // If this JapaneseEra is a supplemental one, obtain the name from
 251         // the era definition.
 252         if (getValue() > N_ERA_CONSTANTS - ERA_OFFSET) {
 253             Objects.requireNonNull(locale, "locale");
 254             return style.asNormal() == TextStyle.NARROW ? getAbbreviation() : getName();
 255         }
 256         return Era.super.getDisplayName(style, locale);
 257     }
 258 
 259     //-----------------------------------------------------------------------
 260     /**
 261      * Obtains an instance of {@code JapaneseEra} from a date.
 262      *
 263      * @param date  the date, not null
 264      * @return the Era singleton, never null
 265      */
 266     static JapaneseEra from(LocalDate date) {
 267         if (date.isBefore(MEIJI_6_ISODATE)) {
 268             throw new DateTimeException("JapaneseDate before Meiji 6 are not supported");
 269         }
 270         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
 271             JapaneseEra era = KNOWN_ERAS[i];
 272             if (date.compareTo(era.since) >= 0) {
 273                 return era;
 274             }
 275         }
 276         return null;
 277     }
 278 
 279     static JapaneseEra toJapaneseEra(sun.util.calendar.Era privateEra) {
 280         for (int i = ERA_CONFIG.length - 1; i >= 0; i--) {
 281             if (ERA_CONFIG[i].equals(privateEra)) {
 282                 return KNOWN_ERAS[i];
 283             }
 284         }
 285         return null;
 286     }
 287 
 288     static sun.util.calendar.Era privateEraFrom(LocalDate isoDate) {
 289         for (int i = KNOWN_ERAS.length - 1; i > 0; i--) {
 290             JapaneseEra era = KNOWN_ERAS[i];
 291             if (isoDate.compareTo(era.since) >= 0) {
 292                 return ERA_CONFIG[i];
 293             }
 294         }
 295         return null;
 296     }
 297 
 298     /**
 299      * Returns the index into the arrays from the Era value.
 300      * the eraValue is a valid Era number, -1..2.
 301      *
 302      * @param eraValue  the era value to convert to the index
 303      * @return the index of the current Era
 304      */
 305     private static int ordinal(int eraValue) {
 306         return eraValue + ERA_OFFSET - 1;
 307     }
 308 
 309     //-----------------------------------------------------------------------
 310     /**
 311      * Gets the numeric era {@code int} value.
 312      * <p>
 313      * The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
 314      * Later eras are numbered from 2 ({@link #HEISEI}).
 315      * Earlier eras are numbered 0 ({@link #TAISHO}), -1 ({@link #MEIJI})).
 316      *
 317      * @return the era value
 318      */
 319     @Override
 320     public int getValue() {
 321         return eraValue;
 322     }
 323 
 324     //-----------------------------------------------------------------------
 325     /**
 326      * Gets the range of valid values for the specified field.
 327      * <p>
 328      * The range object expresses the minimum and maximum valid values for a field.
 329      * This era is used to enhance the accuracy of the returned range.
 330      * If it is not possible to return the range, because the field is not supported
 331      * or for some other reason, an exception is thrown.
 332      * <p>
 333      * If the field is a {@link ChronoField} then the query is implemented here.
 334      * The {@code ERA} field returns the range.
 335      * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
 336      * <p>
 337      * If the field is not a {@code ChronoField}, then the result of this method
 338      * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
 339      * passing {@code this} as the argument.
 340      * Whether the range can be obtained is determined by the field.
 341      * <p>
 342      * The range of valid Japanese eras can change over time due to the nature
 343      * of the Japanese calendar system.
 344      *
 345      * @param field  the field to query the range for, not null
 346      * @return the range of valid values for the field, not null
 347      * @throws DateTimeException if the range for the field cannot be obtained
 348      * @throws UnsupportedTemporalTypeException if the unit is not supported
 349      */
 350     @Override  // override as super would return range from 0 to 1
 351     public ValueRange range(TemporalField field) {
 352         if (field == ERA) {
 353             return JapaneseChronology.INSTANCE.range(ERA);
 354         }
 355         return Era.super.range(field);
 356     }
 357 
 358     //-----------------------------------------------------------------------
 359     String getAbbreviation() {
 360         return ERA_CONFIG[ordinal(getValue())].getAbbreviation();
 361     }
 362 
 363     String getName() {
 364         return ERA_CONFIG[ordinal(getValue())].getName();
 365     }
 366 
 367     @Override
 368     public String toString() {
 369         return getName();
 370     }
 371 
 372     //-----------------------------------------------------------------------
 373     /**
 374      * Defend against malicious streams.
 375      *
 376      * @param s the stream to read
 377      * @throws InvalidObjectException always
 378      */
 379     private void readObject(ObjectInputStream s) throws InvalidObjectException {
 380         throw new InvalidObjectException("Deserialization via serialization delegate");
 381     }
 382 
 383     //-----------------------------------------------------------------------
 384     /**
 385      * Writes the object using a
 386      * <a href="../../../serialized-form.html#java.time.chrono.Ser">dedicated serialized form</a>.
 387      * @serialData
 388      * <pre>
 389      *  out.writeByte(5);        // identifies a JapaneseEra
 390      *  out.writeInt(getValue());
 391      * </pre>
 392      *
 393      * @return the instance of {@code Ser}, not null
 394      */
 395     private Object writeReplace() {
 396         return new Ser(Ser.JAPANESE_ERA_TYPE, this);
 397     }
 398 
 399     void writeExternal(DataOutput out) throws IOException {
 400         out.writeByte(this.getValue());
 401     }
 402 
 403     static JapaneseEra readExternal(DataInput in) throws IOException {
 404         byte eraValue = in.readByte();
 405         return JapaneseEra.of(eraValue);
 406     }
 407 
 408 }