Internationalization and the Java StackPart 1

Matt Wheeler

Notes

• This is a training NOT a presentation• Please ask questions• Prerequisites

– Introduction to Java Stack– Introduction to Spring– Basic Java and XML skills– Installed LdsTech IDE (or other equivalent – good luck

there ;)

Overview

• Internationalization in general• Java Internationalization (ResourceBundle)• Spring Internationalization (MessageSource)• MessageSource vs. ResourceBundle• Spring Helpers

• JSP tags• Locale resolver• Locale change interceptor

Internationalization in General (I18n)

• "Internationalization, in relation to computer programming, is the process of designing and writing an application so that it can be used in a global or multinational context. An internationalized program is capable of supporting different languages, as well as date, time, currency, and other values, without software modification.“

Internationalization (continued)

• "Internationalization is the process of designing software so that it can be adapted (localized) to various languages and regions easily, cost-effectively, and in particular without engineering changes to the software. This generally involves isolating the parts of a program that are dependent on language and culture....“– http://www.ibm.com/developerworks/java/

tutorials/j-i18n/section2.html

Localization (L10n)

• "Localization is the process of adapting a program for use in a specific locale. A locale is a geographic or political region that shares the same language and customs. Localization includes the translation of text such as user interface labels, error messages, and online help. It also includes the culture-specific formatting of data items such as monetary values, times, dates, and numbers."• http://www.ibm.com/developerworks/java/tutorials/j-i18n/

section2.html

Internationalization vs. Localization

• Internationalization is developing the application so that it can handle multiple locales without code change

• Localization is the process of adding a new locale to an application– Includes translation of resources, …

First Steps of Internationalization

• Extract translatable text from code• Load resources for a specific locale• Inject locale specific resources into the

application

Java Internationalization (ResourceBundle)

• ResourceBundle is the cornerstone of Java internationalization– Backed by different data stores

• Property files (PropertyResourceBundle)• Java source code (ListResourceBundle)

• Represents a collection of key/value pairs for a given locale

In Practice

• Property file(s)

• Accessing locale specific resources at runtime

#bundle.properties

abc=where is the beef

#bundle_es.properties#abc=¿dónde está la carne de vaca

abc=\u00a8d\u00a2nde est\u00a0 la carne de vaca

ResourceBundle.getBundle("bundle").getString("abc") //where is the beef

ResourceBundle.getBundle("bundle", new Locale("es")).getString("abc") // ¿dónde está la carne de vaca

ResourceBundle.getBundle("bundle", new Locale("es", "AR")).getString("abc") // ¿dónde está la carne de vaca

Bundle Resolution

• The resolution pattern

• Concrete example

basename + “_” + language1 + “_” + country1 + “_” + variant1 basename + “_” + language1 + “_” + country1 basename + “_” + language1 basename + “_” + language2 + “_” + country2 + “_” + variant2 basename + “_” + language2 + “_” + country2 basename + “_” + language2 basename

messages_pt_BR.propertiesmessages_pt.propertiesmessages_en_GB.propertiesmessages_en_US.propertiesmessages.properties

#basename – messages (and we have a default bundle with that name)# fr would resolve to message.properties# pt_PT_CO would resolve to messages_pt.properties# en would resolve to messages.properties

DEMO

Spring Internationalization (MessageSource)

• MessageSource is the cornerstone of Spring internationalization

• MessageSource interface– An abstraction to the actual text store of translated

resources• Data store can be properties files, database, MarkLogic, …• Implement the interface for the given resource store

– Many MessageSource implementations available out of the box including a basic resource bundle source

MessageSource Example

• Place resource property files in src/main/bundles• Configure the message source as follows:

• MessageSource must have an id of “messageSource”

<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basenames"> <list> <value>classpath:messages</value> <value>classpath:otherbundle</value> </list> </property> <property name="defaultEncoding" value="UTF-8" /></bean>

Inject MessageSource

• Utilize the MessageSource@Injectprivate MessageSource messageSource;

public void getAStringInCode(ModelMap model) { String message = messageSource.getMessage("abc", null, "Default text.", Locale.ENGLISH); //do something with the message return;}

MessageSource vs. ResourceBundle

• MessageSource being an interface is far more extensible

• MessageSource allows all resources to be conglomerated together

• MessageSource does parameter replacement automatically

• MessageSource can set default encoding

#born={0} was born on {1}.

String pattern = ResourceBundle.getBundle("whatever", Locale.ENGLISH).getString("born");MessageFormat.format(pattern, "Billy", new Date())

messageSource.getMessage("born", new Object[] {"Billy", new Date()}, "default", Locale.ENGLISH)

DEMO

Spring MessageSource taglib

• http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/html/spring.tld.html#spring.tld.message

<%@taglib uri="http://www.springframework.org/tags" prefix="spring"%>

<spring:message code="message.key"/><spring:message code="some.key" arguments="aaa, bbb"/>

DEMO

Lab 1: Internationalize a page

https://tech.lds.org/wiki/Internationalization_and_the_Java_Stack_-

_Part_1#Lab_1_Internationalize_a_Page

Spring Internationalization Architecture

• LocaleResolver– Attempts to determine the current user’s locale– Provides a way to set / cache current user’s locale

• LocaleChangeInterceptor– Picks up locale changes (from request parameter by

default)– Sets locale on the resolver

Example Configuration

• Sample native Spring configuration:

• LocaleResolver must have id of “localeResolver”• Now /whatever?sitelanguage=it will change the

locale

<mvc:interceptors> <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor"> <property name="paramName" value="sitelanguage"/> </bean></mvc:interceptors>

<bean id="localeResolver" class="org.springframework.web.servlet.i18n.CookieLocaleResolver"/>

ChainedLocaleResolver

• Based on Spring LocaleResolver interface• Locale resolution on steroids• Sets up multiple locale resolvers from which to

determine the user’s locale

ChainedLocaleResolver (configuration)• Basic configuration

• Or when using WAM

• http://code.lds.org/maven-sites/stack/module.html?module=web-spring/xsddoc/index.html

• http://code.lds.org/maven-sites/stack/module.html?module=web-spring/apidocs/org/lds/stack/web/spring/i18n/ChainedLocaleResolver.html

xmlns:stack-web="http://code.lds.org/schema/spring/web"

<stack-web:locale-resolver />

<stack-web:locale-resolver use-wam-locale= " true" />

Lab 2: Configure Locale Change and Resolution

https://tech.lds.org/wiki/Internationalization_and_the_Java_Stack_-

_Part_1#Lab_2_Configure_Locale_Change_and_Resolution

Credit where credit is due

• http://www.springsource.org/spring-framework#documentation

• http://www.ibm.com/developerworks/java/tutorials/j-i18n/section2.html