Locale in java example

Creating a Locale

There are several ways to create a Locale object. Regardless of the technique used, creation can be as simple as specifying the language code. However, you can further distinguish the locale by setting the region (also referred to as «country») and variant codes. If you are using the JDK 7 release or later, you can also specify the script code and Unicode locale extensions.

The four ways to create a Locale object are:

Version Note: The Locale.Builder class and the forLanguageTag method were added in the Java SE 7 release.

LocaleBuilder Class

The Locale.Builder utility class can be used to construct a Locale object that conforms to the IETF BCP 47 syntax. For example, to specify the French language and the country of Canada, you could invoke the Locale.Builder constructor and then chain the setter methods as follows:

Locale aLocale = new Locale.Builder().setLanguage("fr").setRegion("CA").build();

The next example creates Locale objects for the English language in the United States and Great Britain:

Locale bLocale = new Locale.Builder().setLanguage("en").setRegion("US").build(); Locale cLocale = new Locale.Builder().setLanguage("en").setRegion("GB").build();

The final example creates a Locale object for the Russian language:

Locale dLocale = new Locale.Builder().setLanguage("ru").setScript("Cyrl").build();

Locale Constructors

There are three constructors available in the Locale class for creating a Locale object:

The following examples create Locale objects for the French language in Canada, the English language in the U.S. and Great Britain, and the Russian language.

aLocale = new Locale("fr", "CA"); bLocale = new Locale("en", "US"); cLocale = new Locale("en", "GB"); dLocale = new Locale("ru");

It is not possible to set a script code on a Locale object in a release earlier than JDK 7.

forLanguageTag Factory Method

If you have a language tag string that conforms to the IETF BCP 47 standard, you can use the forLanguageTag(String) factory method, which was introduced in the Java SE 7 release. For example:

Locale aLocale = Locale.forLanguageTag("en-US"); Locale bLocale = Locale.forLanguageTag("ja-JP-u-ca-japanese");

Locale Constants

For your convenience the Locale class provides constants for some languages and countries. For example:

cLocale = Locale.JAPAN; dLocale = Locale.CANADA_FRENCH;

When you specify a language constant, the region portion of the Locale is undefined. The next three statements create equivalent Locale objects:

j1Locale = Locale.JAPANESE; j2Locale = new Locale.Builder().setLanguage("ja").build(); j3Locale = new Locale("ja");

The Locale objects created by the following three statements are also equivalent:

j4Locale = Locale.JAPAN; j5Locale = new Locale.Builder().setLanguage("ja").setRegion("JP").build(); j6Locale = new Locale("ja", "JP");

Codes

The following sections discuss the language code and the optional script, region, and variant codes.

Language Code

The language code is either two or three lowercase letters that conform to the ISO 639 standard. You can find a full list of the ISO 639 codes at http://www.loc.gov/standards/iso639-2/php/code_list.php.

The following table lists a few of the language codes.

Sample Language Codes

Language Code	Description
de	German
en	English
fr	French
ru	Russian
ja	Japanese
jv	Javanese
ko	Korean
zh	Chinese

Script Code

The script code begins with an uppercase letter followed by three lowercase letters and conforms to the ISO 15924 standard. You can find a full list of the ISO 15924 codes at http://unicode.org/iso15924/iso15924-codes.html.

The following table lists a few of the script codes.

Sample Script Codes

Script Code	Description
Arab	Arabic
Cyrl	Cyrillic
Kana	Katakana
Latn	Latin

There are three methods for retrieving the script information for a Locale :

• getScript() – returns the 4-letter script code for a Locale object. If no script is defined for the locale, an empty string is returned.
• getDisplayScript() – returns a name for the locale’s script that is appropriate for display to the user. If possible, the name will be localized for the default locale. So, for example, if the script code is «Latn,» the display script name returned would be the string «Latin» for an English language locale.
• getDisplayScript(Locale) – returns the display name of the specified Locale localized, if possible, for the locale.

Region Code

The region (country) code consists of either two or three uppercase letters that conform to the ISO 3166 standard, or three numbers that conform to the UN M.49 standard. A copy of the codes can be found at http://www.chemie.fu-berlin.de/diverse/doc/ISO_3166.html.

The following table contains several sample country and region codes.

Sample Region Codes

A-2 Code	A-3 Code	Numeric Code	Description
AU	AUS	036	Australia
BR	BRA	076	Brazil
CA	CAN	124	Canada
CN	CHN	156	China
DE	DEU	276	Germany
FR	FRA	250	France
IN	IND	356	India
RU	RUS	643	Russian Federation
US	USA	840	United States

Variant Code

The optional variant code can be used to further distinguish your Locale . For example, the variant code can be used to indicate dialectical differences that are not covered by the region code.

Version Note: Prior to the Java SE 7 release, the variant code was sometimes used to identify differences that were not specific to the language or region. For example, it might have been used to identify differences between computing platforms, such as Windows or UNIX. Under the IETF BCP 47 standard, this use is discouraged.

To define non-language-specific variations relevant to your environment, use the extensions mechanism, as explained in BCP 47 Extensions.

As of the Java SE 7 release, which conforms to the IETF BCP 47 standard, the variant code is used specifically to indicate additional variations that define a language or its dialects. The IETF BCP 47 standard imposes syntactic restrictions on the variant subtag. You can see a list of variant codes (search for variant) at http://www.iana.org/assignments/language-subtag-registry.

For example, Java SE uses the variant code to support the Thai language. By convention, a NumberFormat object for the th and th_TH locales will use common Arabic digit shapes, or Arabic numerals, to format Thai numbers. However, a NumberFormat for the th_TH_TH locale uses Thai digit shapes. The excerpt from ThaiDigits.java demonstrates this:

String outputString = new String(); Locale[] thaiLocale = < new Locale("th"), new Locale("th", "TH"), new Locale("th", "TH", "TH") >; for (Locale locale : thaiLocale)

The following is a screenshot of this sample:

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Lesson: Setting the Locale

An internationalized program can display information differently throughout the world. For example, the program will display different messages in Paris, Tokyo, and New York. If the localization process has been fine-tuned, the program will display different messages in New York and London to account for the differences between American and British English. How does an internationalized program identify the appropriate language and region of its end users? Easy. It references a Locale object.

A Locale object is an identifier for a particular combination of language and region. If a class varies its behavior according to Locale , it is said to be locale-sensitive. For example, the NumberFormat class is locale-sensitive; the format of the number it returns depends on the Locale . Thus NumberFormat may return a number as 902 300 (France), or 902.300 (Germany), or 902,300 (United States). Locale objects are only identifiers. The real work, such as formatting and detecting word boundaries, is performed by the methods of the locale-sensitive classes.

The following sections explain how to work with Locale objects:

Creating a Locale

When creating a Locale object, you usually specify a language code and a country code. A third parameter, the variant, is optional.

BCP 47 Extensions

This section shows you how to add a Unicode locale extension or a private use extension to a Locale.

Identifying Available Locales

Locale-sensitive classes support only certain Locale definitions. This section shows you how to determine which Locale definitions are supported.

Language Tag Filtering and Lookup

This section describes the internationalization support for language tags, language tags filtering, and language tags lookup.

The Scope of a Locale

On the Java platform you do not specify a global Locale by setting an environment variable before running the application. Instead you either rely on the default Locale or assign a Locale to each locale-sensitive object.

Locale-Sensitive Services SPI

This section explains how to enable plug-in of locale-dependent data and services. These SPIs (Service Provider Interface) provides support of more locales in addition to the currently available locales.

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