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.theme; import net.sourceforge.subsonic.service.*; import net.sourceforge.subsonic.domain.*; import org.springframework.web.servlet.*; import javax.servlet.http.*; import java.util.*; /** * Theme resolver implementation which returns the theme selected in the settings. * * @author Sindre Mehus */ public class SubsonicThemeResolver implements ThemeResolver { private SecurityService securityService; private SettingsService settingsService; private Set<String> themeIds; /** * Resolve the current theme name via the given request. * * @param request Request to be used for resolution * @return The current theme name */ public String resolveThemeName(HttpServletRequest request) { String themeId = (String) request.getAttribute("subsonic.theme"); if (themeId != null) { return themeId; } // Optimization: Cache theme in the request. themeId = doResolveThemeName(request); request.setAttribute("subsonic.theme", themeId); return themeId; } private String doResolveThemeName(HttpServletRequest request) { String themeId = null; // Look for user-specific theme. String username = securityService.getCurrentUsername(request); if (username != null) { UserSettings userSettings = settingsService.getUserSettings(username); if (userSettings != null) { themeId = userSettings.getThemeId(); } } if (themeId != null && themeExists(themeId)) { return themeId; } // Return system theme. themeId = settingsService.getThemeId(); return themeExists(themeId) ? themeId : "default"; } /** * Returns whether the theme with the given ID exists. * @param themeId The theme ID. * @return Whether the theme with the given ID exists. */ private synchronized boolean themeExists(String themeId) { // Lazily create set of theme IDs. if (themeIds == null) { themeIds = new HashSet<String>(); Theme[] themes = settingsService.getAvailableThemes(); for (Theme theme : themes) { themeIds.add(theme.getId()); } } return themeIds.contains(themeId); } /** * Set the current theme name to the given one. This method is not supported. * * @param request Request to be used for theme name modification * @param response Response to be used for theme name modification * @param themeName The new theme name * @throws UnsupportedOperationException If the ThemeResolver implementation * does not support dynamic changing of the theme */ public void setThemeName(HttpServletRequest request, HttpServletResponse response, String themeName) { throw new UnsupportedOperationException("Cannot change theme - use a different theme resolution strategy"); } public void setSecurityService(SecurityService securityService) { this.securityService = securityService; } public void setSettingsService(SettingsService settingsService) { this.settingsService = settingsService; } }