Multiple messageSources in Spring configuration files

Question

Hi,

our web application uses Spring 2.5. It consists of several modules, each of which can bring additional Spring context files, which are loaded automatically (into one application context). We want to let each module provide additional resource bundles (for I18N support).

Spring supports internationalization by registering a bean with name messageSource in the configuration file, but this assumes I know exactly what is the fully qualified name of the class or properties file that contained the translates strings. This is a problem because other modules might have their own properties files put in a different location. So I'm looking for a way to let each module define its own messageSource with its own resource bundles and I don't know how to do it.

Does anybody know the solution to this problem?

Thanks.

Answer 1

I have used the Message Sources in Spring for some i18n support. In my case I only needed one so it was easy to inject the one message source I needed into the service bean that I was creating.

I was hoping to see something like what I will propose later on in the Spring sources itself. But I don't see anything that will aggregate heterogeneous message sources. If all of them will be parts of a resource bundle like property files, I'm sure you could write a wrapper for ResourceBundleMessageSource that could be dynamically updated as beans were registered.

However, if you wanted to aggregate heterogeneous MessageSources, this is what I would suggest. Create an message source aggregating bean that upon loading asks the ApplicationContext for beans of type MessageSource.class. This aggregating bean can then let each source attempt to resolve the key and format the message. Depending on how many files/msg source classes you have you may want to allow the aggregating implementation to prioritize which ones it attempts to use first. If performance becomes a problem, you could also cache which source resolved which keys so that the aggregator doesn't have to guess each time.