Global Programming with Java™ 1.1




Cintech Consulting



PO Box 2415
Syracuse, NY 13220-2415 USA
cintech@ix.netcom.com
©1997 Cintech Consulting

Java and Java-based marks are trademarks or registered trademarks of
Sun Microsystems, Inc. in the United States and other countries.
Cintech Consulting is independent of Sun Microsystems, Inc.

Intro

n Internationalization

 

n Locales

 

n ResourceBundles

l The Big Picture

l The ResourceBundle Class

l Using ResourceBundles

l Creating ResourceBundles

 

n The java.text Package

l The DateFormat Class (dates & times)

l The NumberFormat Class (general numbers & currency)

l The MessageFormat Class

 

n Unicode

 

n Conclusion

 

What is a Global Program?

One Way:

Better Way:

n You must identify the locale-specific portions of your program during design

 

n You must create the locale-specific objects for each locale you want to support

 

 

Some Terminology

I18N Internationalization. Separating out the locale-dependent portions of a program.

L10N Localization. Adapting an internationalized program to a specific locale.

Locale A name for a set of user conventions for

l Language

l Date & Time formatting

l Number & Currency formatting

Example: "fr_CH" is French/Switzerland

 

The Locale Class

n In package java.util

 

n Locale objects constructed from

l A language code (ISO 639) such as "en", "fr", "es", etc.

l A country code (ISO 3166) such as "US", "CH", "GB", etc.

l A variant

 

n Constants such as Locale.GERMANY, Locale.GERMAN, etc.

 

n Class methods

l GetDefault()

l setDefault(Locale newLocale)

 

n Instance methods include

l getDisplayCountry()

l getDisplayCountry(Locale inLocale)

 

n A Locale object indentifies a locale, that’s all!

 

Locales
   

ar Arabic (Egypt)

be Belorussian (Belarus)

bg Bulgarian (Bulgaria)

ca Catalan (Spain)

cs Czech (Czech Republic)

da Danish (Denmark)

de German (Germany)

de_AT German (Austria)

de_CH German (Switzerland)

el Greek (Greece)

en English (US)

en_CA English (Canada)

en_GB English (United Kingdom)

en_IE English (Ireland)

es Spanish (Spain)

et Estonian (Estonia)

fi Finnish (Finland)

fr French (France)

fr_BE French (Belgium)

fr_CA French (Canada)

fr_CH French (Switzerland)

hr Croatian (Croatia)

hu Hungarian (Hungary)

is Icelandic (Iceland)

it Italian (Italy)

it_CH Italian (Switzerland)

 

iw Hebrew (Israel)

ja Jananese (Japan)

ko Korean (Korea)

lt Lithuanian (Lituania)

lv Latvian (Latvia)

mk Macedonian (Macedonia)

nl Dutch (Netherlands)

nl_BE Dutch (Belgium)

no Norwegian (Bokmål)
(Norway)

no_NO_NY Norwegian
(Nynorsk) (Norway,NY)

pl Polish (Poland)

pt Portuguese (Portugal)

ro Romanian (Romania)

ru Russian (Russia)

sh Serbian (Latin) (Serbia)

sk Slovak (Slovakia)

sl Slovene (Slovenia)

sq Albanian (Albania)

sr Servian (Cyrillic) (Serbia)

sv Swedish (Sweden)

tr Turkish (Turkey)

uk Ukranian (Ukraine)

zh Chinese (China)

zh_TW Chinese (ROC)

 

 

 

Locale Example

import java.util.Locale;

 

class Example01 {

 

public static void main(String[] args) {

 

String ans = Locale.getDefault().

getDisplayName(Locale.GERMANY);

System.out.println(ans);

}

}

 

 

Produces the following output (in the US):

Englisch (Vereinigte Staaten)

 

Resource Bundles

A ResourceBundle object translates a key into an object.

 

The Big Picture

You must create ResourceBundle classes for the Locales you want to support. Java helps you organize and use them.

 

The ResoureBundle Class

n In package java.util

 

n abstract

 

n Class "factory" methods

l getBundle(String baseName)

l getBundle(String baseName, Locale locale)

where baseName is the name you select when you create your resource bundles

 

n Instance methods include

l GetObject(String key)

l GetString(String key)

 

n A ResourceBundle object provides Locale-specific objects

 

Using ResourceBundles — 1

import java.util.Locale; import java.util.ResourceBundle;

 

public class Ultimate {

 

private static void dumpEm(Locale locale) {

System.out.println("Locale: " + locale);

ResourceBundle rb = ResourceBundle.getBundle

("UltPkg.UltB", locale);

System.out.println(" Title: " +

rb.getString("Title"));

System.out.println(" Button: " +

rb.getString("Button"));

System.out.println();

}

 

public static void main(String[] a) {

 

try {

System.setOut(new java.io.PrintStream

(new java.io.FileOutputStream("C:\\VANCE\\ANS")));

} catch (Exception e) {e.printStackTrace();}

 

dumpEm(Locale.getDefault());

dumpEm(new Locale("en","US"));

dumpEm(new Locale("en","US","Syracuse"));

dumpEm(new Locale("en","US","Rochester"));

dumpEm(new Locale("en","US","Utica"));

dumpEm(new Locale("en","CA"));

dumpEm(new Locale("en","GB"));

dumpEm(new Locale("fr","CA"));

dumpEm(new Locale("fr","BE"));

dumpEm(Locale.FRENCH);

}

}

 

Using ResourceBundles — 2

Output

Locale: en_US

Title: "Title in US English."

Button: "US is great!"

 

Locale: en_US

Title: "Title in US English."

Button: "US is great!"

 

Locale: en_US_SYRACUSE

Title: "Title in US English."

Button: "Syracuse is great!"

 

Locale: en_US_ROCHESTER

Title: "Title in US English."

Button: "Rochester is great!"

 

Locale: en_US_UTICA

Title: "Title in US English."

Button: "US is great!"

 

Locale: en_CA

Title: "Title in Canadian English."

Button: "Canada is great!"

 

Locale: en_GB

Title: "Don't know what language to use."

Button: "Unsupported locale."

 

Locale: fr_CA

Title: "Title in French Canadian."

Button: "Canada est bon!"

 

Locale: fr_BE

Title: "En francais."

Button: "Ici est bon!"

 

Locale: fr

Title: "En francais."

Button: "Ici est bon!"

 

Property Files

If all your resources are Strings, simply create property files.

UltPkg.UltB

Title="Don't know what language to use."

Button="Unsupported locale."

 

UltPkg.UltB_en_CA

 

Title="Title in Canadian English."

Button="Canada is great!"

 

UltPkg.UltB_en_US

Title="Title in US English."

Button="US is great!"

 

UltPkg.UltB_en_US_Syracuse

 

Button="Syracuse is great!"

 

 

UltPkg.UltB_en_US_Rochester

 

Button="Rochester is great!"

 

 

UltPkg.UltB_fr

 

Title="En francais."

Button="Ici est bon!"

 

UltPkg.UltB_fr_CA

 

Title="Title in French Canadian."

Button="Canada est bon!"

 

The ListResourceBundle Class

If your ResourceBundles need to contain other objects besides Strings, use the ListResourceBundle class.

 

package UltPkg;

 

public class UltimateBundle extends java.util.ListResourceBundle {

 

private java.awt.Button button_1 =

new java.awt.Button("Button in English-US");

 

Object[][] contents ={{"Title","Title in English"},

{"Button", button_1}};

 

// Required method.

 

protected Object[][] getContents() {

return (contents);

}

}

 

 

 

Questions

1. What would the output of main be if the Locale were set to "tr" (Turkey)?

2. If you create multiple resource bundles, do you get multiple resources?

3. What would happen if you invoked getObject with a key that wasn’t handled by your resource bundle?

4. How would you modify the design to support the Locales fr and fr_BE (French and French-Belgium)?

5. What would happen if you didn’t put the resource bundles in their own package?

 

 

On to international text manipulation ...

 

The DateFormat Class

n In package java.text

 

n Includes a class method getAvailableLocales()

 

n A DateFormat object is used to read and write dates

 

n A DateFormat object can be obtained from various factory methods in the class, including

l getDateInstance()

l getDateInstance(int style)

l getDateInstance(int style, Locale aLocale)

where style is DEFAULT, FULL, LONG, MEDIUM, or SHORT

 

n Example

 

import java.text.DateFormat;

import java.util.Date;

import java.util.Locale;

 

class DateIt {

 

public static void main (String[] a) {

DateFormat df = DateFormat.getDateInstance
(DateFormat.SHORT,Locale.UK);

System.out.println(df.format(new Date()));

}

}

 

23/09/97

 

The NumberFormat Class

n In package java.text

 

n Includes a class method getAvailableLocales()

 

n A NumberFormat object is used to read and write currency, numbers, and percents

 

n A NumberFormat object can be obtained from various factory methods in the class, including

l getCurrencyInstance(Locale inLocale)

l getNumberInstance(Locale inLocale)

l getPercentInstance(Locale inLocale)

 

n Example

 

import java.text.NumberFormat;

import java.util.Locale;

 

class CashIt {

 

public static void main(String[] a) {

NumberFormat nf = NumberFormat.
getCurrencyInstance(Locale.UK);

System.out.println(nf.format(5.5));

}

}

 

 

ú5.50 (should have been £5.50)

 

The MessageFormat Class

n In package java.text

 

n Provides functionality similar to printf() in C

 

n Example

 

import java.text.MessageFormat;

 

class PrintIt {

 

public static void main(String[] a) {

Object[] numbers = {"1","2","3"};

 

System.out.println(MessageFormat.format

("{0} plus {1} is {2}", numbers));

}

 

}

 

 

1 plus 2 is 3

 

 

The Char Type

n A char value in Java is 16 bits so characters and strings in any language may be represented using the Unicode standard.

Range

Alphabet

0x0000 — 0x007f

Basic Latin (ASCII)

0x0080 — 0x00ff

Latin-1 Supplement
(names for other characters used in Western European languages)

etc

...

 

n The Unicode standard defines a mapping from 16-bit numbers to names (not visual representations)

0x0041 « CAPITAL LATIN LETTER A

0x0f40 « TIBETAN LETTER KA

 

n Fonts map numbers to glyphs (or BELL, DELETE, etc.). A glyph is a visual representation.

0x0041 « A or A or A or A etc.

0x0f40 « or maybe nothing at all ...

l A font may only provide unique glyphs for 7 or 8-bit numbers. It may map other numbers mod 128 or 256.

l A font may map a number to a glyph that has no relation to the Unicode name for that number.

 

Conclusion: You can’t use Java to print Japanese, Hebrew, Greek, whatever unless you have the right font.

 

Netscape 3.0 Unicode Support

Latin-1, Latin-2, Chinese, Japanese, and Korean are supported in Netscape 3.0 as long as the required characters can be rendered with an existing system font.

 

 

 

Example:

 

System.out.println("\u00c5ngstrom"); // prints Ångstrom

 

Creating Java Source

The Java Language Specification states "Java programs are written using the Unicode character set."

In fact, Java source may be written

l In ASCII (each character takes 8 bits)

l In Unicode (each character takes 16 bits)

 

Java source written in Unicode could, for example, contain variable names in Korean.

 

To compile Java source written in Unicode with an ASCII-based compiler, the source must first be translated into ASCII. Each non-ASCII Unicode character is translated into a Unicode escape.

 

We may write Java source in ASCII as if it were translated from Unicode.

Example:

class UniTest {

int \u00c5ngstrom;

}

 

compiles. The variable name is Ångstrom.

 

Java Source Example

An Israeli with the right font could write "Hello World" like this:

 

class {

public static void main(String[ ] ) {

System.out.println("");

}

}

 

 

Conclusion

 

 

 

 

It’s not to soon
to start internationalizing
your Java applications
and applets!