public final class Locale extends Object implements Cloneable, Serializable
Locale object represents a specific geographical, political,
or cultural region. An operation that requires a Locale to perform
its task is called locale-sensitive and uses the Locale
to tailor information for the user. For example, displaying a number
is a locale-sensitive operation— the number should be formatted
according to the customs and conventions of the user's native country,
region, or culture.
The Locale class implements identifiers
interchangeable with BCP 47 (IETF BCP 47, "Tags for Identifying
Languages"), with support for the LDML (UTS#35, "Unicode Locale
Data Markup Language") BCP 47-compatible extensions for locale data
exchange.
A Locale object logically consists of the fields
described below.
Locale always canonicalizes to lower case.[a-zA-Z]{2,8}. Note that this is not the the full
BCP47 language production, since it excludes extlang. They are
not needed since modern three-letter language codes replace
them.Locale always canonicalizes to title case (the first
letter is upper case and the rest of the letters are lower
case).[a-zA-Z]{4}Locale always canonicalizes to upper case.[a-zA-Z]{2} | [0-9]{3}Locale. Where there are two or more variant values
each indicating its own semantics, these values should be ordered
by importance, with most important first, separated by
underscore('_'). The variant field is case sensitive.However, the variant field in Locale has
historically been used for any kind of variation, not just
language variations. For example, some supported variants
available in Java SE Runtime Environments indicate alternative
cultural behaviors such as calendar type or number script. In
BCP 47 this kind of information, which does not identify the
language, is supported by extension subtags or private use
subtags.
SUBTAG
(('_'|'-') SUBTAG)* where SUBTAG =
[0-9][0-9a-zA-Z]{3} | [0-9a-zA-Z]{5,8}. (Note: BCP 47 only
uses hyphen ('-') as a delimiter, this is more lenient).Locale implement the semantics and syntax of BCP 47
extension subtags and private use subtags. The extensions are
case insensitive, but Locale canonicalizes all
extension keys and values to lower case. Note that extensions
cannot have empty values.[0-9a-zA-Z]. Well-formed values have the form
SUBTAG ('-' SUBTAG)* where for the key 'x'
SUBTAG = [0-9a-zA-Z]{1,8} and for other keys
SUBTAG = [0-9a-zA-Z]{2,8} (that is, 'x' allows
single-character subtags).Locale class
does not provide any validation features. The Builder
only checks if an individual field satisfies the syntactic
requirement (is well-formed), but does not validate the value
itself. See Builder for details.
UTS#35, "Unicode Locale Data Markup Language" defines optional attributes and keywords to override or refine the default behavior associated with a locale. A keyword is represented by a pair of key and type. For example, "nu-thai" indicates that Thai local digits (value:"thai") should be used for formatting numbers (key:"nu").
The keywords are mapped to a BCP 47 extension value using the
extension key 'u' (UNICODE_LOCALE_EXTENSION). The above
example, "nu-thai", becomes the extension "u-nu-thai".code
Thus, when a Locale object contains Unicode locale
attributes and keywords,
getExtension(UNICODE_LOCALE_EXTENSION) will return a
String representing this information, for example, "nu-thai". The
Locale class also provides getUnicodeLocaleAttributes(), getUnicodeLocaleKeys(), and
getUnicodeLocaleType(java.lang.String) which allow you to access Unicode
locale attributes and key/type pairs directly. When represented as
a string, the Unicode Locale Extension lists attributes
alphabetically, followed by key/type sequences with keys listed
alphabetically (the order of subtags comprising a key's type is
fixed when the type is defined)
A well-formed locale key has the form
[0-9a-zA-Z]{2}. A well-formed locale type has the
form "" | [0-9a-zA-Z]{3,8} ('-' [0-9a-zA-Z]{3,8})* (it
can be empty, or a series of subtags 3-8 alphanums in length). A
well-formed locale attribute has the form
[0-9a-zA-Z]{3,8} (it is a single subtag with the same
form as a locale type subtag).
The Unicode locale extension specifies optional behavior in locale-sensitive services. Although the LDML specification defines various keys and values, actual locale-sensitive service implementations in a Java Runtime Environment might not support any particular Unicode locale attributes or key/type pairs.
There are several different ways to create a Locale
object.
Using Builder you can construct a Locale object
that conforms to BCP 47 syntax.
The Locale class provides three constructors:
Locale(String language)
Locale(String language, String country)
Locale(String language, String country, String variant)
These constructors allow you to create a Locale object
with language, country and variant, but you cannot specify
script or extensions.
The method #forLanguageTag creates a Locale
object for a well-formed BCP 47 language tag.
The Locale class provides a number of convenient constants
that you can use to create Locale objects for commonly used
locales. For example, the following creates a Locale object
for the United States:
Locale.US
Once you've created a Locale you can query it for information
about itself. Use getCountry to get the country (or region)
code and getLanguage to get the language code.
You can use getDisplayCountry to get the
name of the country suitable for displaying to the user. Similarly,
you can use getDisplayLanguage to get the name of
the language suitable for displaying to the user. Interestingly,
the getDisplayXXX methods are themselves locale-sensitive
and have two versions: one that uses the default locale and one
that uses the locale specified as an argument.
The Java Platform provides a number of classes that perform locale-sensitive
operations. For example, the NumberFormat class formats
numbers, currency, and percentages in a locale-sensitive manner. Classes
such as NumberFormat have several convenience methods
for creating a default object of that type. For example, the
NumberFormat class provides these three convenience methods
for creating a default NumberFormat object:
NumberFormat.getInstance()
NumberFormat.getCurrencyInstance()
NumberFormat.getPercentInstance()
Each of these methods has two variants; one with an explicit locale
and one without; the latter uses the default locale:
NumberFormat.getInstance(myLocale)
NumberFormat.getCurrencyInstance(myLocale)
NumberFormat.getPercentInstance(myLocale)
A Locale is the mechanism for identifying the kind of object
(NumberFormat) that you would like to get. The locale is
just a mechanism for identifying objects,
not a container for the objects themselves.
In order to maintain compatibility with existing usage, Locale's
constructors retain their behavior prior to the Java Runtime
Environment version 1.7. The same is largely true for the
toString method. Thus Locale objects can continue to
be used as they were. In particular, clients who parse the output
of toString into language, country, and variant fields can continue
to do so (although this is strongly discouraged), although the
variant field will have additional information in it if script or
extensions are present.
In addition, BCP 47 imposes syntax restrictions that are not
imposed by Locale's constructors. This means that conversions
between some Locales and BCP 47 language tags cannot be made without
losing information. Thus toLanguageTag cannot
represent the state of locales whose language, country, or variant
do not conform to BCP 47.
Because of these issues, it is recommended that clients migrate
away from constructing non-conforming locales and use the
forLanguageTag and Locale.Builder APIs instead.
Clients desiring a string representation of the complete locale can
then always rely on toLanguageTag for this purpose.
For compatibility reasons, two non-conforming locales are treated as special cases. These are ja_JP_JP and th_TH_TH. These are ill-formed in BCP 47 since the variants are too short. To ease migration to BCP 47, these are treated specially during construction. These two cases (and only these) cause a constructor to generate an extension, all other values behave exactly as they did prior to Java 7.
Java has used ja_JP_JP to represent Japanese as used in Japan together with the Japanese Imperial calendar. This is now representable using a Unicode locale extension, by specifying the Unicode locale key ca (for "calendar") and type japanese. When the Locale constructor is called with the arguments "ja", "JP", "JP", the extension "u-ca-japanese" is automatically added.
Java has used th_TH_TH to represent Thai as used in Thailand together with Thai digits. This is also now representable using a Unicode locale extension, by specifying the Unicode locale key nu (for "number") and value thai. When the Locale constructor is called with the arguments "th", "TH", "TH", the extension "u-nu-thai" is automatically added.
During serialization, writeObject writes all fields to the output stream, including extensions.
During deserialization, readResolve adds extensions as described in Special Cases, only for the two cases th_TH_TH and ja_JP_JP.
Locale's constructor has always converted three language codes to their earlier, obsoleted forms: he maps to iw, yi maps to ji, and id maps to in. This continues to be the case, in order to not break backwards compatibility.
The APIs added in 1.7 map between the old and new language codes,
maintaining the old codes internal to Locale (so that
getLanguage and toString reflect the old
code), but using the new codes in the BCP 47 language tag APIs (so
that toLanguageTag reflects the new one). This
preserves the equivalence between Locales no matter which code or
API is used to construct them. Java's default resource bundle
lookup mechanism also implements this mapping, so that resources
can be named using either convention, see ResourceBundle.Control.
The Locale constructors have always specified that the language and the country param be two characters in length, although in practice they have accepted any length. The specification has now been relaxed to allow language codes of two to eight characters and country (region) codes of two to three characters, and in particular, three-letter language codes and three-digit region codes as specified in the IANA Language Subtag Registry. For compatibility, the implementation still does not impose a length constraint.
Builder,
ResourceBundle,
Format,
NumberFormat,
Collator,
Serialized Form| Modifier and Type | Class and Description |
|---|---|
static class |
Locale.Category
Enum for locale categories.
|
| Modifier and Type | Field and Description |
|---|---|
static Locale |
CANADA
Useful constant for country.
|
static Locale |
CANADA_FRENCH
Useful constant for country.
|
static Locale |
CHINA
Useful constant for country.
|
static Locale |
CHINESE
Useful constant for language.
|
static Locale |
ENGLISH
Useful constant for language.
|
static Locale |
FRANCE
Useful constant for country.
|
static Locale |
FRENCH
Useful constant for language.
|
static Locale |
GERMAN
Useful constant for language.
|
static Locale |
GERMANY
Useful constant for country.
|
static Locale |
ITALIAN
Useful constant for language.
|
static Locale |
ITALY
Useful constant for country.
|
static Locale |
JAPAN
Useful constant for country.
|
static Locale |
JAPANESE
Useful constant for language.
|
static Locale |
KOREA
Useful constant for country.
|
static Locale |
KOREAN
Useful constant for language.
|
static Locale |
PRC
Useful constant for country.
|
static char |
PRIVATE_USE_EXTENSION
The key for the private use extension ('x').
|
static Locale |
ROOT
Useful constant for the root locale.
|
static Locale |
SIMPLIFIED_CHINESE
Useful constant for language.
|
static Locale |
TAIWAN
Useful constant for country.
|
static Locale |
TRADITIONAL_CHINESE
Useful constant for language.
|
static Locale |
UK
Useful constant for country.
|
static char |
UNICODE_LOCALE_EXTENSION
The key for Unicode locale extension ('u').
|
static Locale |
US
Useful constant for country.
|
| Constructor and Description |
|---|
Locale(String language)
Construct a locale from a language code.
|
Locale(String language,
String country)
Construct a locale from language and country.
|
Locale(String language,
String country,
String variant)
Construct a locale from language, country and variant.
|
| Modifier and Type | Method and Description |
|---|---|
Object |
clone()
Overrides Cloneable.
|
boolean |
equals(Object obj)
Indicates whether some other object is "equal to" this one.
|
static Locale[] |
getAvailableLocales()
Returns an array of all installed locales.
|
String |
getCountry()
Returns the country/region code for this locale, which should
either be the empty string, an uppercase ISO 3166 2-letter code,
or a UN M.49 3-digit code.
|
static Locale |
getDefault()
Gets the current value of the default locale for this instance
of the Java Virtual Machine.
|
static Locale |
getDefault(Locale.Category category)
Gets the current value of the default locale for the specified Category
for this instance of the Java Virtual Machine.
|
String |
getExtension(char key)
Returns the extension (or private use) value associated with
the specified key, or null if there is no extension
associated with the key.
|
Set<Character> |
getExtensionKeys()
Returns the set of extension keys associated with this locale, or the
empty set if it has no extensions.
|
String |
getLanguage()
Returns the language code of this Locale.
|
String |
getScript()
Returns the script for this locale, which should
either be the empty string or an ISO 15924 4-letter script
code.
|
Set<String> |
getUnicodeLocaleAttributes()
Returns the set of unicode locale attributes associated with
this locale, or the empty set if it has no attributes.
|
Set<String> |
getUnicodeLocaleKeys()
Returns the set of Unicode locale keys defined by this locale, or the empty set if
this locale has none.
|
String |
getUnicodeLocaleType(String key)
Returns the Unicode locale type associated with the specified Unicode locale key
for this locale.
|
String |
getVariant()
Returns the variant code for this locale.
|
int |
hashCode()
Override hashCode.
|
static void |
setDefault(Locale newLocale)
Sets the default locale for this instance of the Java Virtual Machine.
|
String |
toString()
Returns a string representation of this
Locale
object, consisting of language, country, variant, script,
and extensions as below: |
public static final Locale ENGLISH
public static final Locale FRENCH
public static final Locale GERMAN
public static final Locale ITALIAN
public static final Locale JAPANESE
public static final Locale KOREAN
public static final Locale CHINESE
public static final Locale SIMPLIFIED_CHINESE
public static final Locale TRADITIONAL_CHINESE
public static final Locale FRANCE
public static final Locale GERMANY
public static final Locale ITALY
public static final Locale JAPAN
public static final Locale KOREA
public static final Locale CHINA
public static final Locale PRC
public static final Locale TAIWAN
public static final Locale UK
public static final Locale US
public static final Locale CANADA
public static final Locale CANADA_FRENCH
public static final Locale ROOT
public static final char PRIVATE_USE_EXTENSION
getExtension(char),
Builder#setExtension(char, String),
Constant Field Valuespublic static final char UNICODE_LOCALE_EXTENSION
getExtension(char),
Builder#setExtension(char, String),
Constant Field Valuespublic Locale(String language, String country, String variant)
Note:
language - An ISO 639 alpha-2 or alpha-3 language code, or a language subtag
up to 8 characters in length. See the Locale class description about
valid language values.country - An ISO 3166 alpha-2 country code or a UN M.49 numeric-3 area code.
See the Locale class description about valid country values.variant - Any arbitrary value used to indicate a variation of a Locale.
See the Locale class description for the details.NullPointerException - thrown if any argument is null.public Locale(String language, String country)
Note:
language - An ISO 639 alpha-2 or alpha-3 language code, or a language subtag
up to 8 characters in length. See the Locale class description about
valid language values.country - An ISO 3166 alpha-2 country code or a UN M.49 numeric-3 area code.
See the Locale class description about valid country values.NullPointerException - thrown if either argument is null.public Locale(String language)
Note:
language - An ISO 639 alpha-2 or alpha-3 language code, or a language subtag
up to 8 characters in length. See the Locale class description about
valid language values.NullPointerException - thrown if argument is null.public static Locale getDefault()
The Java Virtual Machine sets the default locale during startup
based on the host environment. It is used by many locale-sensitive
methods if no locale is explicitly specified.
It can be changed using the
setDefault method.
public static Locale getDefault(Locale.Category category)
The Java Virtual Machine sets the default locale during startup based on the host environment. It is used by many locale-sensitive methods if no locale is explicitly specified. It can be changed using the setDefault(Locale.Category, Locale) method.
category - - the specified category to get the default localeNullPointerException - - if category is null#setDefault(Locale.Category, Locale)public static void setDefault(Locale newLocale)
If there is a security manager, its checkPermission
method is called with a PropertyPermission("user.language", "write")
permission before the default locale is changed.
The Java Virtual Machine sets the default locale during startup based on the host environment. It is used by many locale-sensitive methods if no locale is explicitly specified.
Since changing the default locale may affect many different areas of functionality, this method should only be used if the caller is prepared to reinitialize locale-sensitive code running within the same Java Virtual Machine.
By setting the default locale with this method, all of the default locales for each Category are also set to the specified default locale.
newLocale - the new default localeSecurityException - if a security manager exists and its
checkPermission method doesn't allow the operation.NullPointerException - if newLocale is nullSecurityManager.checkPermission(java.security.Permission),
PropertyPermissionpublic static Locale[] getAvailableLocales()
LocaleServiceProvider
implementations. It must contain at least a Locale
instance equal to Locale.US.public String getLanguage()
Note: ISO 639 is not a stable standard— some languages' codes have changed. Locale's constructor recognizes both the new and the old codes for the languages whose codes have changed, but this function always returns the old code. If you want to check for a specific language whose code has changed, don't do
if (locale.getLanguage().equals("he")) // BAD!
...
Instead, do
if (locale.getLanguage().equals(new Locale("he").getLanguage()))
...
#getDisplayLanguagepublic String getScript()
#getDisplayScriptpublic String getCountry()
#getDisplayCountrypublic String getVariant()
#getDisplayVariantpublic String getExtension(char key)
[0-9A-Za-z]. Keys are case-insensitive, so
for example 'z' and 'Z' represent the same extension.key - the extension keyIllegalArgumentException - if key is not well-formedPRIVATE_USE_EXTENSION,
UNICODE_LOCALE_EXTENSIONpublic Set<Character> getExtensionKeys()
public Set<String> getUnicodeLocaleAttributes()
public String getUnicodeLocaleType(String key)
key - the Unicode locale keyIllegalArgumentException - if the key is not well-formedNullPointerException - if key is nullpublic Set<String> getUnicodeLocaleKeys()
public final String toString()
Locale
object, consisting of language, country, variant, script,
and extensions as below:
language + "_" + country + "_" + (variant + "_#" | "#") + script + "-" + extensionsLanguage is always lower case, country is always upper case, script is always title case, and extensions are always lower case. Extensions and private use subtags will be in canonical order as explained in
#toLanguageTag.
When the locale has neither script nor extensions, the result is the same as in Java 6 and prior.
If both the language and country fields are missing, this function will return the empty string, even if the variant, script, or extensions field is present (you can't have a locale with just a variant, the variant must accompany a well-formed language or country code).
If script or extensions are present and variant is missing, no underscore is added before the "#".
This behavior is designed to support debugging and to be compatible with
previous uses of toString that expected language, country, and variant
fields only. To represent a Locale as a String for interchange purposes, use
#toLanguageTag.
Examples:
public Object clone()
public int hashCode()
hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public boolean equals(Object obj)
Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
x and y, multiple invocations of
x.equals(y) consistently return true
or consistently return false, provided no
information used in equals comparisons on the
objects is modified.
x,
x.equals(null) should return false.
The equals method for class Object implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x and
y, this method returns true if and only
if x and y refer to the same object
(x == y has the value true).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode method, which states
that equal objects must have equal hash codes.
equals in class Objectobj - the reference object with which to compare.true if this object is the same as the obj
argument; false otherwise.Object.hashCode(),
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