JSF 2.0 - switching locale with h:commandLink - message bundle not in synch

Question

In my xhtml page I have the following tag included:

<f:view locale="#{languageBean.locale}">
...
</f:view>

I have implemented a language bean:

@ManagedBean(name = "languageBean")
@SessionScoped
public class LanguageBean implements Serializable {

  private static final long serialVersionUID = -4260383661321467037L;

  ...    

  private Locale locale = FacesContext.getCurrentInstance().getViewRoot().getLocale();

  public String switchToDE() {
    LOGGER.info("switching to german");
    Locale german = Locale.GERMAN;
    FacesContext.getCurrentInstance().getViewRoot().setLocale(german);
    this.locale = german;
    return null;
  }

  public String switchToEN() {
    LOGGER.info("switching to english");
    Locale english = Locale.ENGLISH;
    FacesContext.getCurrentInstance().getViewRoot().setLocale(english);
    this.locale = english;
    return null;
  }

  public Locale getLocale() {
    return locale;
  }

  public void setLocale(final Locale locale) {
    this.locale = locale;
  }

}

Then I want to render commandLinks to switch locale:

<ul>
  <li>
      <h:form>
          <h:commandLink class="" action="#{languageBean.switchToDE}">Deutsch</h:commandLink>
      </h:form>
  </li>
  <li>
      <h:form>
          <h:commandLink action="#{languageBean.switchToEN}">English</h:commandLink>
    </h:form>
  </li>
</ul>

On some places in my page I have some outputs where I render messages:

#{msg['message.key.1']

In my faces-config.xml I have configured:

<locale-config>
  <default-locale>de</default-locale>
  <supported-locale>de</supported-locale>
  <supported-locale>en</supported-locale>
</locale-config>

Now my problem: the first click visits the switch locale method but the message bundles are not refreshed in the page. If I click a second time on the same language the message bundle is updated. The message bundle lookup is always one step behind the locale switching. How could I switch locale with h:commandButton tag (I need a link and the style guide disallow to use a or ) so the message bundle lookup is in sync?

I am using GF 2.1 with Mojarra 2.0.9 (JSF 2.0 based on Servlet API 2.5). Any advice is welcome.

EDIT:

Ok, I found out that it was my fault cause we try some "special" things ;-)

I try to explain what we have and what we try:

we are building our software with maven
we have separated logically different web apps for different business purposes in the SVN repo
during build time we aggregate all web apps into one (WAR-overlay)
therefore we have for each business purposed web app a faces-config-<business-webapp-id>.xml registered
each web app has it's own resource bundle registered with the name "<business-webapp-id>msg"
we have a common webapp (framework) which renders navigation items for all registered web apps
each web has the possibility to register nav-items.
the framework now tries to aggregate all resource bundles into one big ressource bundles during the phase where the current navigation items will be returned.

I found out that the method "getItems()" on our navigation bean is called before the switchLocale method is triggered and therefore the switching of the locale is too late.

Now I try to ask if there is the possibility to switch the locale with the h:commandLink or maybe with a h:outputLink so that the switching of the locale take place before the backing bean method for "getItems()" is triggered?

I hope that I have explained my "challenge" so that it is understandable.

In your real code, didn't you use ajax to switch the language? To exclude one and other, what if you redirect back or return non-null? (e.g. empty string) — BalusC, Mar 15 '12 at 15:30
I don't use ajax to switch the locale. And I return null cause the switching of the locale should be possible on every page and therefore I don't know the exact outcome at this moment. And how could I redirect back in a JSF backing bean? — Walter, Mar 16 '12 at 08:49
Do `return "";` instead of `return null;` to force JSF to create a new view, or do `return viewRoot.getViewId() + "?faces-redirect=true";` to force JSF to send a redirect to the same view. — BalusC, Mar 16 '12 at 11:17
Thanks a lot. The "getViewId()" and the redirect directive did the trick for me. You saved my day!!!! — Walter, Mar 16 '12 at 12:11

score 2 · Accepted Answer · answered Mar 16 '12 at 12:15

I'm not sure how and why this problem is caused. You can try the following in order to force JSF to recreate the view. Instead of returning null on action methods, return an empty string or force a redirect to the same view.

public String switchToDE() {
    // ...
    return "";
}

or

public String switchToDE() {
    // ...
    return FacesContext.getCurrentInstance().getViewRoot().getViewId() + "?faces-redirect=true";
}

Unrelated to the concrete question, if your environment supports EL 2.2, it would be more DRY if you use a single action method for this. E.g.

public String switchLanguage(String language) {
    // ...
}

with

<h:commandLink action="#{languageBean.switchLanguage('EN')}">English</h:commandLink>

Thanks a lot. As I said before the redirect and the getViewId() did the trick for me and is really sufficient. I have refactored the stuff already to a single method as you mention it here. Cause we are running in Glassfish 2.1 we cannot use the EL with the parameter therefor I added a tag to populate the chosen locale first. — Walter, Mar 16 '12 at 12:19

JSF 2.0 - switching locale with h:commandLink - message bundle not in synch

1 Answers1