Nengo (Time4J-Base 5.8 API)

java.lang.Object
- net.time4j.calendar.Nengo

All Implemented Interfaces:

Serializable, CalendarEra
```
public final class Nengo
extends Object
implements CalendarEra, Serializable
```
The system of Japanese eras from AD 701 until today.
It is possible to register a new nengo by setting the system property "net.time4j.calendar.japanese.supplemental.era". Its value is a sequence of key-value-pairs (without any space or tab). The keys "name" (given in romaji), "kanji" (japanese - 2 chars) and "since" (ISO-8601-date) are mandatory. If necessary, the optional keys "chinese" (2 chars), "korean" or "russian" can be specified, too. Example:

"-Dnet.time4j.calendar.japanese.supplemental.era name=newEra,kanji=KK,since=9999-12-31"

Since:

3.32/4.27

Author:

Meno Hochschild

See Also:

Serialized Form

Concurrency:
This class is immutable and can be used by multiple threads in parallel.

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class Nengo.Selector
Represents a strategy how to select nengos.

Nested Classes
Modifier and Type	Class and Description
`static class`	`Nengo.Selector` Represents a strategy how to select nengos.

Field Summary

Fields
Modifier and Type	Field and Description
`static Nengo`	`HEISEI` Heisei is valid from 1989-01-08 until 2019-04-30 (emperor Akihito).
`static Nengo`	`MEIJI` Meji is valid from year 1868 until 1912-07-29.
`static Nengo`	`NEWEST` The newest known nengo.
`static Nengo`	`REIWA` Reiwa is valid from 2019-05-01 onwards (emperor Naruhito).
`static AttributeKey<Nengo.Selector>`	`SELECTOR` Format attribute which helps to resolve possible ambivalences in parsing.
`static Nengo`	`SHOWA` Shōwa is valid from 1926-12-25 until 1989-01-07.
`static Nengo`	`TAISHO` Taishō is valid from 1912-07-30 until 1926-12-24.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`equals(Object obj)`
`Optional<Nengo>`	`findNext()` Tries to find the next nengo in chronological order.
`Optional<Nengo>`	`findPrevious()` Tries to find the previous nengo in chronological order.
`String`	`getDisplayName(Locale locale)` Equivalent to `getDisplayName(locale, TextWidth.WIDE)`.
`String`	`getDisplayName(Locale locale, TextWidth width)` Obtains the localized name.
`int`	`getFirstRelatedGregorianYear()` Obtains the gregorian year which relates to the first day of associated Japanese year where this nengo was used the first time.
`PlainDate`	`getStart()` Obtains the first date when this nengo took effect.
`int`	`hashCode()`
`boolean`	`isModern()` Determines if this nengo is used by modern Japan (since Meiji).
`static List<Nengo>`	`list()` Obtains a list of all official nengos in chronological ascending order.
`static List<Nengo>`	`list(Nengo.Selector selector)` Obtains a list of all nengos in chronological ascending order selected by given selector.
`boolean`	`matches(Nengo.Selector selector)` Does this nengo match given selector?
`String`	`name()` Obtains a descriptive text with romaji and the relevant year interval.
`static Nengo`	`ofKanji(String kanji)` Tries to find a suitable nengo for given japanese kanji representation.
`static Nengo`	`ofRelatedGregorianYear(int year)` Obtains the official nengo for given related gregorian year.
`static Nengo`	`ofRelatedGregorianYear(int year, Nengo.Selector selector)` Obtains the nengo for given related gregorian year and selector strategy.
`static List<Nengo>`	`parseRomaji(String romaji)` Tries to find suitable nengos for given representation in romaji.
`static Stream<Nengo>`	`stream()` Obtains a stream of all official nengos in chronological ascending order.
`static Stream<Nengo>`	`stream(Nengo.Selector selector)` Obtains a stream of all nengos in chronological ascending order selected by given selector.
`String`	`toString()`

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - MEIJI
```
public static final Nengo MEIJI
```
    Meji is valid from year 1868 until 1912-07-29.
    
    It uses the lunisolar calendar until end of year 1872.
  - TAISHO
```
public static final Nengo TAISHO
```
    Taishō is valid from 1912-07-30 until 1926-12-24.
  - SHOWA
```
public static final Nengo SHOWA
```
    Shōwa is valid from 1926-12-25 until 1989-01-07.
  - HEISEI
```
public static final Nengo HEISEI
```
    Heisei is valid from 1989-01-08 until 2019-04-30 (emperor Akihito).
  - REIWA
```
public static final Nengo REIWA
```
    Reiwa is valid from 2019-05-01 onwards (emperor Naruhito).
    
    Since:
    
    5.3
  - NEWEST
```
public static final Nengo NEWEST
```
    The newest known nengo.
  - SELECTOR
```
public static final AttributeKey<Nengo.Selector> SELECTOR
```
    Format attribute which helps to resolve possible ambivalences in parsing.
    Standard value is: Nengo.Selector.OFFICIAL
- Method Detail
  - ofRelatedGregorianYear
```
public static Nengo ofRelatedGregorianYear(int year)
```
    Obtains the official nengo for given related gregorian year.
    
    In case two or more nengos happen for one given year, Time4J will choose the latest nengo whose first related gregorian year is still smaller than or equal to given year.
    
    Parameters:
    
    year - the gregorian year which relates to the first day of any Japanese year (New Year)
    
    Returns:
    
    found nengo
    
    Throws:
    
    IllegalArgumentException - if no suitable nengo could be found for given year
    
    See Also:
    
    Nengo.Selector.OFFICIAL, ofRelatedGregorianYear(int, Selector)
  - ofRelatedGregorianYear
```
public static Nengo ofRelatedGregorianYear(int year,
                                           Nengo.Selector selector)
```
    Obtains the nengo for given related gregorian year and selector strategy.
    
    In case two or more nengos happen for one given year, Time4J will choose the latest nengo whose first related gregorian year is still smaller than or equal to given year.
    
    Parameters:
    
    year - the gregorian year which relates to the first day of any Japanese year (New Year)
    
    selector - strategy how to select nengos
    
    Returns:
    
    found nengo
    
    Throws:
    
    IllegalArgumentException - if no suitable nengo could be found for given parameters
  - ofKanji
```
public static Nengo ofKanji(String kanji)
```
    Tries to find a suitable nengo for given japanese kanji representation.
    
    Parameters:
    
    kanji - the representation in japanese kanji
    
    Returns:
    
    suitable nengo with same kanji
    
    Throws:
    
    IllegalArgumentException - if no suitable nengo could be found for given kanji representation
  - parseRomaji
```
public static List<Nengo> parseRomaji(String romaji)
```
    Tries to find suitable nengos for given representation in romaji.
    
    The internal parser is case-insensitive and able to translate vowels with circumflex into vowels with macron. Some labels are ambivalent. One single nengo can even have more than one romaji representation. For example, the label "Shōwa" has existed three times in history (for different nengos). Here the first nengo "Jōwa" (year 834) was also read as "Shōwa".
    
    Parameters:
    
    romaji - the representation in romaji (hepburn variant)
    
    Returns:
    
    unmodifiable list of suitable nengos maybe empty
  - stream
```
public static Stream<Nengo> stream()
```
    Obtains a stream of all official nengos in chronological ascending order.
    
    Returns:
    
    stream of nengos
    
    See Also:
    
    Nengo.Selector.OFFICIAL, stream(Selector)
  - stream
```
public static Stream<Nengo> stream(Nengo.Selector selector)
```
    Obtains a stream of all nengos in chronological ascending order selected by given selector.
    
    Parameters:
    
    selector - strategy how to select nengos
    
    Returns:
    
    stream of nengos
  - list
```
public static List<Nengo> list()
```
    Obtains a list of all official nengos in chronological ascending order.
    
    Returns:
    
    unmodifiable list of nengos
    
    See Also:
    
    Nengo.Selector.OFFICIAL, list(Selector)
  - list
```
public static List<Nengo> list(Nengo.Selector selector)
```
    Obtains a list of all nengos in chronological ascending order selected by given selector.
    
    Parameters:
    
    selector - strategy how to select nengos
    
    Returns:
    
    unmodifiable list of nengos
  - matches
```
public boolean matches(Nengo.Selector selector)
```
    Does this nengo match given selector?
    
    Parameters:
    
    selector - strategy how to select nengos
    
    Returns:
    
    true if given selector would select this nengo else false
  - getFirstRelatedGregorianYear
```
public int getFirstRelatedGregorianYear()
```
    Obtains the gregorian year which relates to the first day of associated Japanese year where this nengo was used the first time.
    
    Returns:
    
    related gregorian year
    
    See Also:
    
    getStart()
  - getStart
```
public PlainDate getStart()
```
    Obtains the first date when this nengo took effect.
    
    Due to the differences between old Japanese calendar and modern gregorian variant, it is possible that the year of start date deviates from the related gregorian year. An example is the nengo Eichō with the related gregorian year 1096 although it started first on AD-1096-01-03 (julian).
    
    Returns:
    
    gregorian date of first introduction of this nengo
    
    See Also:
    
    getFirstRelatedGregorianYear()
  - isModern
```
public boolean isModern()
```
    Determines if this nengo is used by modern Japan (since Meiji).
    
    Returns:
    
    boolean
  - getDisplayName
```
public String getDisplayName(Locale locale)
```
    Equivalent to getDisplayName(locale, TextWidth.WIDE).
    
    Parameters:
    
    locale - the language which determines the name to be displayed
    
    Returns:
    
    localized display name
    
    See Also:
    
    getDisplayName(Locale, TextWidth)
  - getDisplayName
```
public String getDisplayName(Locale locale,
                             TextWidth width)
```
    Obtains the localized name.
    
    For all modern nengos (Meiji or later), the display name will be determined on base of best efforts, possibly in narrow or abbreviated notation, too. However, older nengos are localized in a simplified manner: There is no support for abbreviated or narrow text forms, and the localization is limited to the languages Japanese, Chinese, Korean and Russian (based on Wikipedia). All other languages will be printed using the hebonshiki romaji system.
    
    Parameters:
    
    locale - the language which determines the name to be displayed
    
    width - text width (not relevant for older nengos)
    
    Returns:
    
    localized display name
  - findNext
```
public Optional<Nengo> findNext()
```
    Tries to find the next nengo in chronological order.
    
    Note: If this nengo represents a nengo of northern court in the Nanboku-chō period (1336-1392) then the next nengo will be the next one of northern court only but not of southern court. If this nengo is the last one of northern court then the next nengo will be Ōei (1394).
    
    Returns:
    
    next nengo which is only present if this nengo is not the newest nengo
  - findPrevious
```
public Optional<Nengo> findPrevious()
```
    Tries to find the previous nengo in chronological order.
    
    Note: If this nengo represents a nengo of northern court in the Nanboku-chō period (1336-1392) then the previous nengo will be the previous one of northern court only but not of southern court. If this nengo is the first one of northern court then the previous nengo will be Genkō: (1391).
    
    Returns:
    
    previous nengo which is only present if this nengo is not the first nengo
  - name
```
public String name()
```
    Obtains a descriptive text with romaji and the relevant year interval.
    
    Specified by:
    
    name in interface CalendarEra
    
    Returns:
    
    String
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class Nengo

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MEIJI

TAISHO

SHOWA

HEISEI

REIWA

NEWEST

SELECTOR

Method Detail

ofRelatedGregorianYear

ofRelatedGregorianYear

ofKanji

parseRomaji

stream

stream

list

list

matches

getFirstRelatedGregorianYear

getStart

isModern

getDisplayName

getDisplayName

findNext

findPrevious

name

equals

hashCode

toString