JapaneseEra.java
/*
* Copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
*
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* modification, are permitted provided that the following conditions are met:
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package org.threeten.bp.chrono;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.util.Arrays;
import java.util.concurrent.atomic.AtomicReference;
import org.threeten.bp.DateTimeException;
import org.threeten.bp.LocalDate;
import org.threeten.bp.jdk8.DefaultInterfaceEra;
import org.threeten.bp.jdk8.Jdk8Methods;
import org.threeten.bp.temporal.ChronoField;
import org.threeten.bp.temporal.TemporalField;
import org.threeten.bp.temporal.ValueRange;
/**
* An era in the Japanese Imperial calendar system.
* <p>
* This class defines the valid eras for the Japanese chronology.
* Japan introduced the Gregorian calendar starting with Meiji 6.
* Only Meiji and later eras are supported;
* dates before Meiji 6, January 1 are not supported.
* <p>
* The four supported eras are hard-coded.
* A single additional era may be registered using {@link #registerEra(LocalDate, String)}.
*
* <h3>Specification for implementors</h3>
* This class is immutable and thread-safe.
*/
public final class JapaneseEra
extends DefaultInterfaceEra
implements Serializable {
// The offset value to 0-based index from the era value.
// i.e., getValue() + ERA_OFFSET == 0-based index; except that -999 is mapped to zero
static final int ERA_OFFSET = 2;
/**
* The singleton instance for the 'Meiji' era (1868-09-08 - 1912-07-29)
* which has the value -1.
*/
public static final JapaneseEra MEIJI = new JapaneseEra(-1, LocalDate.of(1868, 9, 8), "Meiji");
/**
* The singleton instance for the 'Taisho' era (1912-07-30 - 1926-12-24)
* which has the value 0.
*/
public static final JapaneseEra TAISHO = new JapaneseEra(0, LocalDate.of(1912, 7, 30), "Taisho");
/**
* The singleton instance for the 'Showa' era (1926-12-25 - 1989-01-07)
* which has the value 1.
*/
public static final JapaneseEra SHOWA = new JapaneseEra(1, LocalDate.of(1926, 12, 25), "Showa");
/**
* The singleton instance for the 'Heisei' era (1989-01-08 - 2019-04-30)
* which has the value 2.
*/
public static final JapaneseEra HEISEI = new JapaneseEra(2, LocalDate.of(1989, 1, 8), "Heisei");
/**
* The singleton instance for the 'Reiwa' era (2019-05-01 - current)
* which has the value 3.
*/
public static final JapaneseEra REIWA = new JapaneseEra(3, LocalDate.of(2019, 5, 1), "Reiwa");
/**
* The value of the additional era.
*/
private static final int ADDITIONAL_VALUE = 4;
/**
* Serialization version.
*/
private static final long serialVersionUID = 1466499369062886794L;
// array for the singleton JapaneseEra instances
private static final AtomicReference<JapaneseEra[]> KNOWN_ERAS;
static {
JapaneseEra[] array = new JapaneseEra[5];
array[0] = MEIJI;
array[1] = TAISHO;
array[2] = SHOWA;
array[3] = HEISEI;
array[4] = REIWA;
KNOWN_ERAS = new AtomicReference<JapaneseEra[]>(array);
}
/**
* The era value.
* @serial
*/
private final int eraValue;
// the first day of the era
private final transient LocalDate since;
// the name of the era
private final transient String name;
/**
* Creates an instance.
*
* @param eraValue the era value, validated
* @param since the date representing the first date of the era, validated not null
* @param name the name
*/
private JapaneseEra(int eraValue, LocalDate since, String name) {
this.eraValue = eraValue;
this.since = since;
this.name = name;
}
/**
* Returns the singleton {@code JapaneseEra} corresponding to this object.
* It's possible that this version of {@code JapaneseEra} doesn't support the latest era value.
* In that case, this method throws an {@code ObjectStreamException}.
*
* @return the singleton {@code JapaneseEra} for this object
* @throws ObjectStreamException if the deserialized object has any unknown numeric era value.
*/
private Object readResolve() throws ObjectStreamException {
try {
return of(eraValue);
} catch (DateTimeException e) {
InvalidObjectException ex = new InvalidObjectException("Invalid era");
ex.initCause(e);
throw ex;
}
}
//-----------------------------------------------------------------------
/**
* Registers an additional instance of {@code JapaneseEra}.
* <p>
* A new Japanese era can begin at any time.
* This method allows one new era to be registered without the need for a new library version.
* If needed, callers should assign the result to a static variable accessible
* across the application. This must be done once, in early startup code.
* <p>
* NOTE: This method does not exist in Java SE 8.
*
* @param since the date representing the first date of the era, validated not null
* @param name the name
* @return the {@code JapaneseEra} singleton, not null
* @throws DateTimeException if an additional era has already been registered
*/
public static JapaneseEra registerEra(LocalDate since, String name) {
JapaneseEra[] known = KNOWN_ERAS.get();
if (known.length > 5) {
throw new DateTimeException("Only one additional Japanese era can be added");
}
Jdk8Methods.requireNonNull(since, "since");
Jdk8Methods.requireNonNull(name, "name");
if (!since.isAfter(REIWA.since)) {
throw new DateTimeException("Invalid since date for additional Japanese era, must be after Reiwa");
}
JapaneseEra era = new JapaneseEra(ADDITIONAL_VALUE, since, name);
JapaneseEra[] newArray = Arrays.copyOf(known, 6);
newArray[5] = era;
if (!KNOWN_ERAS.compareAndSet(known, newArray)) {
throw new DateTimeException("Only one additional Japanese era can be added");
}
return era;
}
/**
* Obtains an instance of {@code JapaneseEra} from an {@code int} value.
* <p>
* The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1
* Later era is numbered 2 ({@link #HEISEI}). Earlier eras are numbered 0 ({@link #TAISHO}),
* -1 ({@link #MEIJI}), only Meiji and later eras are supported.
*
* @param japaneseEra the era to represent
* @return the {@code JapaneseEra} singleton, not null
* @throws DateTimeException if the value is invalid
*/
public static JapaneseEra of(int japaneseEra) {
JapaneseEra[] known = KNOWN_ERAS.get();
if (japaneseEra < MEIJI.eraValue || japaneseEra > known[known.length - 1].eraValue) {
throw new DateTimeException("japaneseEra is invalid");
}
return known[ordinal(japaneseEra)];
}
/**
* Returns the {@code JapaneseEra} with the name.
* <p>
* The string must match exactly the name of the era.
* (Extraneous whitespace characters are not permitted.)
*
* @param japaneseEra the japaneseEra name; non-null
* @return the {@code JapaneseEra} singleton, never null
* @throws IllegalArgumentException if there is not JapaneseEra with the specified name
*/
public static JapaneseEra valueOf(String japaneseEra) {
Jdk8Methods.requireNonNull(japaneseEra, "japaneseEra");
JapaneseEra[] known = KNOWN_ERAS.get();
for (JapaneseEra era : known) {
if (japaneseEra.equals(era.name)) {
return era;
}
}
throw new IllegalArgumentException("Era not found: " + japaneseEra);
}
/**
* Returns an array of JapaneseEras.
* <p>
* This method may be used to iterate over the JapaneseEras as follows:
* <pre>
* for (JapaneseEra c : JapaneseEra.values())
* System.out.println(c);
* </pre>
*
* @return an array of JapaneseEras
*/
public static JapaneseEra[] values() {
JapaneseEra[] known = KNOWN_ERAS.get();
return Arrays.copyOf(known, known.length);
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code JapaneseEra} from a date.
*
* @param date the date, not null
* @return the Era singleton, never null
*/
static JapaneseEra from(LocalDate date) {
if (date.isBefore(MEIJI.since)) {
throw new DateTimeException("Date too early: " + date);
}
JapaneseEra[] known = KNOWN_ERAS.get();
for (int i = known.length - 1; i >= 0; i--) {
JapaneseEra era = known[i];
if (date.compareTo(era.since) >= 0) {
return era;
}
}
return null;
}
/**
* Returns the index into the arrays from the Era value.
* the eraValue is a valid Era number, -999, -1..2.
* @param eraValue the era value to convert to the index
* @return the index of the current Era
*/
private static int ordinal(int eraValue) {
return eraValue + 1;
}
/**
* Returns the start date of the era.
* @return the start date
*/
LocalDate startDate() {
return since;
}
/**
* Returns the end date of the era.
* @return the end date
*/
LocalDate endDate() {
int ordinal = ordinal(eraValue);
JapaneseEra[] eras = values();
if (ordinal >= eras.length - 1) {
return LocalDate.MAX;
}
return eras[ordinal + 1].startDate().minusDays(1);
}
//-----------------------------------------------------------------------
/**
* Returns the numeric value of this {@code JapaneseEra}.
* <p>
* The {@link #SHOWA} era that contains 1970-01-01 (ISO calendar system) has the value 1.
* Later eras are numbered from 2 ({@link #HEISEI}).
* Earlier eras are numbered 0 ({@link #TAISHO}) and -1 ({@link #MEIJI}).
*
* @return the era value
*/
@Override
public int getValue() {
return eraValue;
}
@Override
public ValueRange range(TemporalField field) {
if (field == ChronoField.ERA) {
return JapaneseChronology.INSTANCE.range(ChronoField.ERA);
}
return super.range(field);
}
//-----------------------------------------------------------------------
@Override
public String toString() {
return name;
}
//-----------------------------------------------------------------------
private Object writeReplace() {
return new Ser(Ser.JAPANESE_ERA_TYPE, this);
}
void writeExternal(DataOutput out) throws IOException {
out.writeByte(this.getValue());
}
static JapaneseEra readExternal(DataInput in) throws IOException {
byte eraValue = in.readByte();
return JapaneseEra.of(eraValue);
}
}