/*
 * Copyright (c) 2010 by Intevation GmbH
 *
 * This program is free software under the LGPL (>=v2.1)
 * Read the file LGPL.txt coming with the software for details
 * or visit http://www.gnu.org/licenses/ if it does not exist.
 */

package de.intevation.gnv.action;

import de.intevation.gnv.action.sessionmodel.SessionModel;
import de.intevation.gnv.action.sessionmodel.SessionModelFactory;
import de.intevation.gnv.artifactdatabase.objects.ArtifactObject;

import java.util.Locale;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

import org.apache.struts.Globals;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

/**
 * Toggle the current language used to create the user interface. Two
 * languages are available now - german and english.
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public class SwitchLanguageAction extends DescribeUIAction {

    public static Logger logger = Logger.getLogger(SwitchLanguageAction.class);

    @Override
    public ActionForward execute(
        ActionMapping       mapping,
        ActionForm          form,
        HttpServletRequest  request,
        HttpServletResponse response
    ) throws Exception
    {
        if (isSessionExhausted(request)) {
            return sessionExhaustedForward(mapping, form, request, response);
        }

        SessionModelFactory factory = SessionModelFactory.getInstance();
        SessionModel        sm      = factory.getSessionModel(request);
        Locale locale               = switchLanguage(sm.getCurrentLocale());

        sm.setCurrentLocale(locale);
        ArtifactObject artifactFactory = sm.getSelectedArtifactFactory();

        if (artifactFactory == null) {
            request.getSession().setAttribute(Globals.LOCALE_KEY, locale);
            return mapping.findForward(SUCCSESS_FORWARD_ID);
        }

        return super.execute(mapping, form, request, response);
    }


    /**
     * This method toggles between german and english language.
     *
     * @param currentLocale The locale which is currently used.
     * @return an english locale, if the current locale is german - otherwise
     * a german locale.
     */
    protected Locale switchLanguage(Locale currentLocale) {
        if (currentLocale.getLanguage().equals(Locale.GERMAN.getLanguage())) {
            logger.info("Switch from german to english locale.");
            return Locale.ENGLISH;
        }
        else {
            logger.info("Switch from english to german locale.");
            return Locale.GERMAN;
        }
    }
}
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