Internationalization in the Java StackMatt 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

• Stack provided internationalizaton tools• Message source expression language resolver• JS Message source

• Internationalization best practices• Internationalization testing

• Dynamic pseudo translation

Expression Language Resolver

• Provide message resolver can be utilized in EL

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

<%@ taglib prefix="web-spring" uri="http://code.lds.org/web/spring" %>

<!-- This makes the internationalized properties of the default MessageSource available as a map in the specified scope--><web-spring:message-source var="messages" scope="request"/>

<!- Reference the messages in EL by key -->${messages['abc.def.ghi']}

JavaScript Source

• JS Configuration<bean id="messageSourceController" class="org.lds.stack.web.spring.i18n.MessageSourceController"> <property name="messageSource" ref="messageSource" /></bean>

<!-- Create adapter to handle all non-annotation controllers --><bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>

<!-- Map the properties url to the controller --><bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="/messageSource.js">messageSourceController</prop> </props> </property> <property name="order" value="#{T(org.springframework.core.Ordered).HIGHEST_PRECEDENCE}"/></bean>

MessageSource with JS

• Usage in a JSP page<script charset="utf-8" src="${pageContext['request'].contextPath}/messageSource.js" type="text/javascript"></script>

<script type="text/javascript"> alert(msgs['abc']);</script>

Some I18n Best Practices

• Externalize ALL translatable text• Do not concatenate translations• Create duplicate / separate resources• Avoid text in images

Externalize ALL Text

• Page label - "Name: “• "Name:" including the colon, and not just "Name" externalized

– Otherwise require contatenation - the “Name”coming out of the bundle with : on the page

• : and associated formatting can be different in different languages– It might also be in a different order

Do NOT Concatenate Translations

• For example:

• Attempted usage

key1=Someone namedkey2=likes hiking.

${messages['key1']} Billy ${messages['key2']}

More Correct Way

• Create a single string with replaceable parameters

• Sentence maintains context – Parameters can be moved around to accommodate

language grammar• For example:

• And then it will be used as follows:

key=Someone named {0} likes hiking.

<spring:message code="key" arguments="${hikersName}" text="Default text."/>

Create Separate Resources

• Counter intuitive to code reuse concept• Same English strings should not be shared

• Within the same application, or even the same page• Create a separate key value pair for each occurrence

• Words change based on context• Concept of masculine and/or feminine, age classes, … • Or usage

• Similar English words may not be similar in another language

Avoid Placing Text in Images

• An image that contains text will require a new image for each language

• It will also require a custom way to load the image• Impose the text over the image, using .css or other ingenious

alternative– Then the text can be stored in the resource bundles with all other

strings– And it won’t require a new image for each language

I18n Testing (Dynamic Pseudo Translation)

• Configured to translate for specified locales• Simplifies testing

– Expansion– Special characters– Completeness– zz locale

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

Dynamic Pseudo Translation

• The trick (delegate)<!-- Application Message Bundle --><bean id="messageSource" class="org.lds.stack.web.spring.i18n.message.PseudoMessageSourceFacade"> <constructor-arg ref="delegatingMessageSource" /></bean>

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

Lab

asdf

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