Java tutorial
/* This file is part of Subsonic. Subsonic is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. Subsonic is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Subsonic. If not, see <http://www.gnu.org/licenses/>. Copyright 2009 (C) Sindre Mehus */ package net.sourceforge.subsonic.i18n; import net.sourceforge.subsonic.service.*; import net.sourceforge.subsonic.domain.*; import org.springframework.web.servlet.*; import javax.servlet.http.*; import java.util.*; /** * Locale resolver implementation which returns the locale selected in the settings. * * @author Sindre Mehus */ public class SubsonicLocaleResolver implements LocaleResolver { private SecurityService securityService; private SettingsService settingsService; private Set<Locale> locales; /** * Resolve the current locale via the given request. * * @param request Request to be used for resolution. * @return The current locale. */ public Locale resolveLocale(HttpServletRequest request) { Locale locale = (Locale) request.getAttribute("subsonic.locale"); if (locale != null) { return locale; } // Optimization: Cache locale in the request. locale = doResolveLocale(request); request.setAttribute("subsonic.locale", locale); return locale; } private Locale doResolveLocale(HttpServletRequest request) { Locale locale = null; // Look for user-specific locale. String username = securityService.getCurrentUsername(request); if (username != null) { UserSettings userSettings = settingsService.getUserSettings(username); if (userSettings != null) { locale = userSettings.getLocale(); } } if (locale != null && localeExists(locale)) { return locale; } // Return system locale. locale = settingsService.getLocale(); return localeExists(locale) ? locale : Locale.ENGLISH; } /** * Returns whether the given locale exists. * @param locale The locale. * @return Whether the locale exists. */ private synchronized boolean localeExists(Locale locale) { // Lazily create set of locales. if (locales == null) { locales = new HashSet<Locale>(Arrays.asList(settingsService.getAvailableLocales())); } return locales.contains(locale); } public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) { throw new UnsupportedOperationException( "Cannot change locale - use a different locale resolution strategy"); } public void setSecurityService(SecurityService securityService) { this.securityService = securityService; } public void setSettingsService(SettingsService settingsService) { this.settingsService = settingsService; } }