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Java Fundamental Classes Reference

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1.6 The java.text Package

The java.text package is new in Java 1.1. It contains classes that support the parsing and formatting of data. These classes also support the internationalization of Java programs. Internationalization refers to the process of making a program flexible enough to run correctly in any locale. An internationalized program must, however, be localized to enable it to run in a particular locale. The internationalization capabilities in Java are quite significant, especially in this age of the global Internet.

Many of the classes in java.text are meant to handle formatting string representations of dates, times, numbers, and messages based on the conventions of a locale. The Format class is the superclass of all of the classes that generate and parse string representations of various types of data.

The DateFormat class formats and parses dates and times according to the customs and language of a particular locale. By the same token, the NumberFormat class formats and parses numbers, including currency values, in a locale-dependent manner. The MessageFormat class creates a textual message from a pattern string, while ChoiceFormat maps numerical ranges to strings. By themselves, these classes do not provide different results for different locales. However, they can be used in conjunction with ResourceBundle objects from java.util that generate locale-specific pattern strings.

The Collator class handles collating strings according to the rules of a particular locale. Different languages have different characters and different rules for sorting those characters; Collator and its subclass, RuleBasedCollator, are designed to take those differences into account when collating strings. In addition, the CollationKey class optimizes the sorting of a large collection of strings.

The BreakIterator class finds various boundaries, such as word boundaries and line boundaries, in textual data. As you might expect, BreakIterator locates these boundaries according to the rules of a particular locale.

See Chapter 16, The java.text Package, for complete reference material on all of the classes in the java.text package.

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