Spring Message Resource Bundles - Suitable for white labelling and versioning? - spring-mvc

Question

I wonder if anyone can help. We are putting together a Spring MVC & Webflow app, and want to put all screen text etc in a database backed message resource bundle. I've got a simple implementation of this working no problem. However, we need to support white labeling the application, including versioning of the text.
When I say 'white labeling' I mean that the core application needs to be branded for different commercial brands. The css elements of the branding is easy - we will be using Spring Themes. But the branding extends to different screen text. For example, brandX might ask "What is your name", and brandY might ask "Please enter your name".
In addition, we need to support versioning of the screen text per brand. This is give a consistent user journey and message to a customer - eg: if they see a given set of screen labels on day 1 and save their quote, they should see the same set of screen labels etc when they retrieve their quote on day 10, even if there have been 5 iterations of screen text for that brand in the mean time. (in reality the frequency of changes wont be that often, but we still need to support it)
I've been playing with this for a while, and in my early experimentation thought I could simply prefix the message keys in the resource bundle:
brandX.firstName = What is your firstname?
brandY.firstName = Please enter your firstname
But this feels wrong on several counts.
Unless we have a view per brand (which we might have to), then the view needs to somehow apply the prefix based on either something in the model or the theme. It feels wrong for the view to know about the model in order to select the right messages to display
I dont know how to apply versioning (other than adding it to the composite key = brandX.firstname.v2 = What is your firstname?)
All in all, I'm coming to the conclusion that this is not what message resource bundles are for - they are great for locale based internationalisation (which is what they are for!), but now I am trying to do something quite different with them. It feels that message resource bundles as a solution may not be right for my requirement.
Has anyone else done anything like this? How did you go about solving it?
Cheers
Nathan

Answer 1

I've done something similar to this with a themed web app that could be deployed with different themes or branding. I also needed to have slightly different labels depending on the "brand" being deployed.
The solution I used was to specify the same i18n code in the JSP page but to select the appropriate message bundle according the "brand" being used in the particular deployed instance. So instead of selecting different message bundles according to conventional (language-based) locale, I forced Spring to select a custom i18n bundle by specifying the custom locale via a org.springframework.web.servlet.i18n.CookieLocaleResolver. This in turn was configured by a particular property in the app's main properties file. Here's some of my dispatcher-servlet.xml file:
<bean id="localeChangeInterceptor" class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor">
<property name="paramName" value="lang" />
</bean>
<bean id="localeResolver" class="org.springframework.web.servlet.i18n.CookieLocaleResolver">
<property name="defaultLocale" value="${i18n.code}"/><!-- value from app.properties -->
</bean>
<bean id="handlerMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="interceptors">
<ref bean="localeChangeInterceptor" />
</property>
</bean>
The only hand-cranking needed was in deployment of a particular branded version - a shell script did the deployment and it copied a particular properties file, e.g., cp app.properties.BRAND_X app.properties (the other file that needed manipulating was web.xml).
Edit: not sure about the versioning part but you could probably pull that out of the app.properties file as well but specify it in the JSP like:
<!-- custom tag that reads a properties file -->
<c:set var="version"><app:propertyLoader bundle="app" property="site.version"/></c:set>
<fmt:message key="form.firstName.${version}"/>