001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.servlet.theme; 018 019import javax.servlet.http.HttpServletRequest; 020import javax.servlet.http.HttpServletResponse; 021 022import org.springframework.lang.Nullable; 023import org.springframework.util.StringUtils; 024import org.springframework.web.util.WebUtils; 025 026/** 027 * {@link org.springframework.web.servlet.ThemeResolver} implementation that 028 * uses a theme attribute in the user's session in case of a custom setting, 029 * with a fallback to the default theme. This is most appropriate if the 030 * application needs user sessions anyway. 031 * 032 * <p>Custom controllers can override the user's theme by calling 033 * {@code setThemeName}, e.g. responding to a theme change request. 034 * 035 * @author Jean-Pierre Pawlak 036 * @author Juergen Hoeller 037 * @since 17.06.2003 038 * @see #setThemeName 039 */ 040public class SessionThemeResolver extends AbstractThemeResolver { 041 042 /** 043 * Name of the session attribute that holds the theme name. 044 * Only used internally by this implementation. 045 * Use {@code RequestContext(Utils).getTheme()} 046 * to retrieve the current theme in controllers or views. 047 * @see org.springframework.web.servlet.support.RequestContext#getTheme 048 * @see org.springframework.web.servlet.support.RequestContextUtils#getTheme 049 */ 050 public static final String THEME_SESSION_ATTRIBUTE_NAME = SessionThemeResolver.class.getName() + ".THEME"; 051 052 053 @Override 054 public String resolveThemeName(HttpServletRequest request) { 055 String themeName = (String) WebUtils.getSessionAttribute(request, THEME_SESSION_ATTRIBUTE_NAME); 056 // A specific theme indicated, or do we need to fallback to the default? 057 return (themeName != null ? themeName : getDefaultThemeName()); 058 } 059 060 @Override 061 public void setThemeName( 062 HttpServletRequest request, @Nullable HttpServletResponse response, @Nullable String themeName) { 063 064 WebUtils.setSessionAttribute(request, THEME_SESSION_ATTRIBUTE_NAME, 065 (StringUtils.hasText(themeName) ? themeName : null)); 066 } 067 068}