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.support;
018
019import java.util.Locale;
020import java.util.Map;
021import java.util.TimeZone;
022
023import javax.servlet.http.HttpServletRequest;
024import javax.servlet.http.HttpServletResponse;
025import javax.servlet.jsp.PageContext;
026import javax.servlet.jsp.jstl.core.Config;
027
028import org.springframework.lang.Nullable;
029
030/**
031 * JSP-aware (and JSTL-aware) subclass of RequestContext, allowing for
032 * population of the context from a {@code javax.servlet.jsp.PageContext}.
033 *
034 * <p>This context will detect a JSTL locale attribute in page/request/session/application
035 * scope, in addition to the fallback locale strategy provided by the base class.
036 *
037 * @author Juergen Hoeller
038 * @since 1.1.4
039 * @see #getFallbackLocale
040 */
041public class JspAwareRequestContext extends RequestContext {
042
043        private PageContext pageContext;
044
045
046        /**
047         * Create a new JspAwareRequestContext for the given page context,
048         * using the request attributes for Errors retrieval.
049         * @param pageContext current JSP page context
050         */
051        public JspAwareRequestContext(PageContext pageContext) {
052                this(pageContext, null);
053        }
054
055        /**
056         * Create a new JspAwareRequestContext for the given page context,
057         * using the given model attributes for Errors retrieval.
058         * @param pageContext current JSP page context
059         * @param model the model attributes for the current view
060         * (can be {@code null}, using the request attributes for Errors retrieval)
061         */
062        public JspAwareRequestContext(PageContext pageContext, @Nullable Map<String, Object> model) {
063                super((HttpServletRequest) pageContext.getRequest(), (HttpServletResponse) pageContext.getResponse(),
064                                pageContext.getServletContext(), model);
065                this.pageContext = pageContext;
066        }
067
068
069        /**
070         * Return the underlying PageContext.
071         * Only intended for cooperating classes in this package.
072         */
073        protected final PageContext getPageContext() {
074                return this.pageContext;
075        }
076
077        /**
078         * This implementation checks for a JSTL locale attribute in page,
079         * request, session or application scope; if not found, returns the
080         * {@code HttpServletRequest.getLocale()}.
081         */
082        @Override
083        protected Locale getFallbackLocale() {
084                if (jstlPresent) {
085                        Locale locale = JstlPageLocaleResolver.getJstlLocale(getPageContext());
086                        if (locale != null) {
087                                return locale;
088                        }
089                }
090                return getRequest().getLocale();
091        }
092
093        /**
094         * This implementation checks for a JSTL time zone attribute in page,
095         * request, session or application scope; if not found, returns {@code null}.
096         */
097        @Override
098        protected TimeZone getFallbackTimeZone() {
099                if (jstlPresent) {
100                        TimeZone timeZone = JstlPageLocaleResolver.getJstlTimeZone(getPageContext());
101                        if (timeZone != null) {
102                                return timeZone;
103                        }
104                }
105                return null;
106        }
107
108
109        /**
110         * Inner class that isolates the JSTL dependency.
111         * Just called to resolve the fallback locale if the JSTL API is present.
112         */
113        private static class JstlPageLocaleResolver {
114
115                @Nullable
116                public static Locale getJstlLocale(PageContext pageContext) {
117                        Object localeObject = Config.find(pageContext, Config.FMT_LOCALE);
118                        return (localeObject instanceof Locale ? (Locale) localeObject : null);
119                }
120
121                @Nullable
122                public static TimeZone getJstlTimeZone(PageContext pageContext) {
123                        Object timeZoneObject = Config.find(pageContext, Config.FMT_TIME_ZONE);
124                        return (timeZoneObject instanceof TimeZone ? (TimeZone) timeZoneObject : null);
125                }
126        }
127
128}