Internationalization and the Java Stack
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 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, costeffectively, 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/ji18n/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
For example
• Property file(s)
#bundle.properties
abc=some string
#bundle_it.properties
abc=some Italian string
• Accessing the resource
ResourceBundle.getBundle("bundle").getString("abc")
//some string
ResourceBundle.getBundle("bundle", Locale.ITALIAN).getString("abc")
//some Italian string
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 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
@Inject
private 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 allows all resources to be
conglomerated together
• MessageSource does parameter replacement
automatically
• MessageSource allows for a default (in case
message is not found)
• 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/spri
ng-frameworkreference/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:
<mvc:interceptors>
<bean ref="localeChangeInterceptor" />
</mvc:interceptors>
<bean id="localeChangeInterceptor"
class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
<property name="paramName" value="siteLanguage"/>
</bean>
<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
xmlns:stack-web="http://code.lds.org/schema/spring/web"
<stack-web:locale-resolver />
• Or when using WAM
<stack-web:locale-resolver use-wam-locale= " true" />
• code.lds.org/maven-sites/stack/module.html?module=webspring/xsddoc/index.html
• code.lds.org/maven-sites/stack/module.html?module=webspring/apidocs/org/lds/stack/web/spring/i18n/ChainedLocaleR
esolver.html
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
Spring MessageSource taglib
Credit where credit is due
• http://www.ibm.com/developerworks/java/tutor
ials/j-i18n/section2.html