Internationalization in the Java StackMatt Wheeler

Notes

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

– Introduction to Java Stack– 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 change interceptor• Locale resolver

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

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 basis 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

For example

• Property file(s)

• Accessing the resourceResourceBundle.getBundle("bundle").getString("abc") //some string

ResourceBundle.getBundle("bundle", Locale.ITALIAN).getString("abc") //some Italian string

#bundle.properties

abc=some string

#bundle_it.properties

abc=some Italian string

DEMO

Spring Internationalization (MessageSource)

• MessageSource is the root 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

– Implementation of MessageSource can use resource bundles as in native Java

MessageSource Example

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

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

Inject MessageSource

• Utilize the MessageSource@Injectprivate MessageSource messageSource;

@RequestMapping(value="/", method=RequestMethod.GET)public void getAStringInCode(ModelMap model) { String message = messageSource.getMessage("abc", null, "default", Locale.US); //do something with message return;}

MessageSource vs. ResourceBundle

• MessageSource allows all resources to be conglomerated together

• MessageSource does parameter replacement automatically

• MessageSource allows for a default (in case message is not found)

#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)

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"/>

DEMO

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

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

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

• 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" />

Spring MessageSource taglib

Lab 1: Internationalize a page

https://tech.lds.org/wiki/Introduction_to_Spring#Lab_2_Dependency_Inje

ction

Credit where credit is due

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