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Java in a Nutshell

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11. Internationalization

A Word About Locales
Character Encodings
Handling Local Customs
Localizing User-Visible Messages
Formatted Messages

Internationalization is the process of making a program flexible enough to run correctly in any locale, as discussed in Chapter 4, What's New in Java 1.1. The required corollary to internationalization is localization--the process of arranging for a program to run in a specific locale.

There are several distinct steps to the task of internationalization. Java 1.1 addresses these steps with several different mechanisms:

This chapter discusses all three of these aspects of internationalization.

11.1 A Word About Locales

A locale represents a geographic, political, or cultural region. In Java 1.1, locales are represented by the java.util.Locale class. A locale is frequently defined by a language, which is represented by its standard lowercase two-letter code, such as en (English) or fr (French). Sometimes, however, language alone is not sufficient to uniquely specify a locale, and a country is added to the specification. A country is represented by an uppercase two-letter code. For example, the United States English locale (en_US) is distinct from the British English locale (en_GB), and the French spoken in Canada (fr_CA) is different from the French spoken in France (fr_FR). Occasionally, the scope of a locale is further narrowed with the addition of a system-dependent "variant" string.

The Locale class maintains a static default locale, which can be set and queried with Locale.setDefault() and Locale.getDefault(). Locale-sensitive methods in Java 1.1 typically come in two forms. One uses the default locale and the other uses a Locale object that is explicitly specified as an argument. A program can create and use any number of non-default Locale objects, although it is more common simply to rely on the default locale, which is inherited from the underlying default locale on the native platform. Locale-sensitive classes in Java often provide a method to query the list of locales that they support.

Finally, note that AWT components in Java 1.1 have a locale property, so it is possible for different components to use different locales. (Most components, however, are not locale-sensitive; they behave the same in any locale.)

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