internationalization in JSF with ResourceBundle entries which are loaded from database

Internationalization/localization should preferably be entirely done in the view side. The model shouldn't be aware of this.

In JSF, the <resource-bundle> entry in faces-config.xml and the <f:loadBundle> in XHTML can also point to a fullworthy ResourceBundle class instead of basename of .properties files. In Java SE 6 there's a new ResourceBundle.Control API available which allows full control over loading and filling the bundle.

Knowing those facts, it should be possible to load the bundle messages from the DB with a custom ResourceBundle and Control. Here's a kickoff example:

public class CompetenceBundle extends ResourceBundle {    protected static final String BASE_NAME = "Competence.messages"; // Can be name of @NamedQuery    protected static final Control DB_CONTROL = new DBControl();    private Map<String, String> messages;    public CompetenceBundle() {        setParent(ResourceBundle.getBundle(BASE_NAME,             FacesContext.getCurrentInstance().getViewRoot().getLocale(), DB_CONTROL));    }    protected CompetenceBundle(Map<String, String> messages) {        this.messages = messages;    }    @Override    protected Object handleGetObject(String key) {        return messages != null ? messages.get(key) : parent.getObject(key);    }    @Override    public Enumeration<String> getKeys() {        return messages != null ? Collections.enumeration(messages.keySet()) : parent.getKeys();    }    protected static class DBControl extends Control {        @Override        public ResourceBundle newBundle            (String baseName, Locale locale, String format, ClassLoader loader, boolean reload)                throws IllegalAccessException, InstantiationException, IOException        {            String language = locale.getLanguage();            Map<String, String> messages = getItSomehow(baseName, language); // Do your JPA thing. The baseName can be used as @NamedQuery name.            return new CompetenceBundle(messages);        }    }}

This way you can declare it as follows in faces-config.xml:

<resource-bundle>    <base-name>com.example.i18n.CompetenceBundle</base-name>    <var>competenceBundle</var></resource-bundle>

Or as follows in the Facelet:

<f:loadBundle basename="com.example.i18n.CompetenceBundle" var="competenceBundle" />

Either way, you can use it the usual way:

<h:outputText value="#{competenceBundle.name}" />

I would move the language specific part from your model into recource bundles. Just model Competence, Language and User. If a user requests a page, you display his competence and lookup the language specific competence (CompetenceName) from the recource bundle.

I searched for sample code to get you started and found this, see Listing 19.16 customerDetails.jsp.

Something like:

<fmt:message key="${competence}" />