Question

I have set up i18n in Spring MVC 3, and it is working correctly.
There are several files, each with its own language: messages_en.properties, messages_de.properties, etc.

In one of my JSPs, I need to show the users a combo with all available languages, and I would like this list to be dynamic i.e. generated on the fly from the existing language files in the server.

Is there any built-in method to generate this list? Or do I have to resort to check the folder where the language files reside and parse them?

Thanks!

Nacho

Answer 1

Ok, two solutions found. For both, assume they are being executed inside a Spring MVC @Controller-annotated class. Each will produce a HashMap (languages) in which the key is the 2-letter ISO language code, and the value the language name (in the current Locale, which in these examples is a static variable called HSConstants.currentLocale)

1.- The one submitted by @millhouse (see above/below), which works after a bit of tweaking:

    HashMap languages = new HashMap();  
    final String defaultMessage = "NOT FOUND";  
    HashMap availableLocales = new HashMap();  
    for (Locale locale : Locale.getAvailableLocales()) {  
        String msg = rrbms.getMessage("currentLanguage", null, defaultMessage, locale);  
        if (!defaultMessage.equals(msg) && !availableLocales.containsKey(locale.getLanguage())){  
            availableLocales.put(locale.getLanguage(), locale);  
        }  
    }  
    for (String c : availableLocales.keySet()){  
        languages.put(c, availableLocales.get(c).getDisplayLanguage(HSConstants.currentLocale));  
    }  
    model.addAttribute("languages", languages);  

This solution requires that, in each of your language .properties files, you set an entry with the language (in the example above, it would be ‘currentLanguage’). For ecample, in messages_it.properties, there must be an entry like this: currentLanguage=Italiano

2.- Raw method, i.e. accesing the folder/files directly: assuming the files languages are in /WEB-INF/languages, and have a basename of fr-messages:

HashMap languages = new HashMap();  
String languagesFolderPath = request.getSession().getServletContext().getRealPath("/WEB-INF/languages");  
File folder = new File(languagesFolderPath);  
File[] listOfFiles = folder.listFiles();  

for (int i = 0; i < listOfFiles.length; i++){  
   String fileName = listOfFiles[i].getName();  
   if (fileName.startsWith("fr-messages_") && fileName.endsWith(".properties")){  
      // Extract the language code, which is between the underscore and the .properties extension  
      String language = fileName.substring(12, fileName.indexOf(".properties"));  
      Locale l = new Locale(language);  
      languages.put(language, l.getDisplayLanguage(HSConstants.currentLocale));  
   }  
}  
model.addAttribute("languages", languages);  

And then, in your JSP, render the select box using the languages map:

<select name="language">
    <c:forEach items="${languages}" var="language">
        <c:choose>
            <c:when test="${platform.language == language.key}">
                <option value="${language.key}" selected="SELECTED">${language.value}</option>
            </c:when>
            <c:otherwise>
                <option value="${language.key}">${language.value}</option>
            </c:otherwise>
        </c:choose>                         
    </c:forEach>
</select>