alpha.portal.webapp.filter.LocaleFilter.java Source code

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Here is the source code for alpha.portal.webapp.filter.LocaleFilter.java

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/**************************************************************************
 * alpha-Portal: A web portal, for managing knowledge-driven 
 * ad-hoc processes, in form of case files.
 * ==============================================
 * Copyright (C) 2011-2012 by 
 *   - Christoph P. Neumann (http://www.chr15t0ph.de)
 *   - and the SWAT 2011 team
 **************************************************************************
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and 
 * limitations under the License.
 **************************************************************************
 * $Id$
 *************************************************************************/
package alpha.portal.webapp.filter;

import java.io.IOException;
import java.util.Locale;
import java.util.Map;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.jstl.core.Config;

import org.appfuse.Constants;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.web.filter.OncePerRequestFilter;

/**
 * Filter to wrap request with a request including user preferred locale.
 */
public class LocaleFilter extends OncePerRequestFilter {

    /**
     * This method looks for a "locale" request parameter. If it finds one, it
     * sets it as the preferred locale and also configures it to work with JSTL.
     * 
     * @param request
     *            the current request
     * @param response
     *            the current response
     * @param chain
     *            the chain
     * @throws IOException
     *             when something goes wrong
     * @throws ServletException
     *             when a communication failure happens
     */
    @Override
    @SuppressWarnings("unchecked")
    public void doFilterInternal(HttpServletRequest request, final HttpServletResponse response,
            final FilterChain chain) throws IOException, ServletException {

        final String locale = request.getParameter("locale");
        Locale preferredLocale = null;

        if (locale != null) {
            final int indexOfUnderscore = locale.indexOf('_');
            if (indexOfUnderscore != -1) {
                final String language = locale.substring(0, indexOfUnderscore);
                final String country = locale.substring(indexOfUnderscore + 1);
                preferredLocale = new Locale(language, country);
            } else {
                preferredLocale = new Locale(locale);
            }
        }

        final HttpSession session = request.getSession(false);

        if (session != null) {
            if (preferredLocale == null) {
                preferredLocale = (Locale) session.getAttribute(Constants.PREFERRED_LOCALE_KEY);
            } else {
                session.setAttribute(Constants.PREFERRED_LOCALE_KEY, preferredLocale);
                Config.set(session, Config.FMT_LOCALE, preferredLocale);
            }

            if ((preferredLocale != null) && !(request instanceof LocaleRequestWrapper)) {
                request = new LocaleRequestWrapper(request, preferredLocale);
                LocaleContextHolder.setLocale(preferredLocale);
            }
        }

        final String theme = request.getParameter("theme");
        if ((theme != null) && request.isUserInRole(Constants.ADMIN_ROLE)) {
            final Map<String, Object> config = (Map) this.getServletContext().getAttribute(Constants.CONFIG);
            config.put(Constants.CSS_THEME, theme);
        }

        chain.doFilter(request, response);

        // Reset thread-bound LocaleContext.
        LocaleContextHolder.setLocaleContext(null);
    }
}