/*
* Copyright 2002-2008 the original author or authors.
*
* 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.
*/
package org.springframework.web.servlet.support;
import java.util.Locale;
import java.util.ResourceBundle;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.jstl.core.Config;
import javax.servlet.jsp.jstl.fmt.LocalizationContext;
import org.springframework.context.MessageSource;
import org.springframework.context.support.MessageSourceResourceBundle;
import org.springframework.context.support.ResourceBundleMessageSource;
/**
* Helper class for preparing JSTL views,
* in particular for exposing a JSTL localization context.
*
* @author Juergen Hoeller
* @since 20.08.2003
*/
public abstract class JstlUtils {
/**
* Checks JSTL's "javax.servlet.jsp.jstl.fmt.localizationContext"
* context-param and creates a corresponding child message source,
* with the provided Spring-defined MessageSource as parent.
* @param servletContext the ServletContext we're running in
* (to check JSTL-related context-params in <code>web.xml</code>)
* @param messageSource the MessageSource to expose, typically
* the ApplicationContext of the current DispatcherServlet
* @return the MessageSource to expose to JSTL; first checking the
* JSTL-defined bundle, then the Spring-defined MessageSource
* @see org.springframework.context.ApplicationContext
*/
public static MessageSource getJstlAwareMessageSource(
ServletContext servletContext, MessageSource messageSource) {
if (servletContext != null) {
String jstlInitParam = servletContext.getInitParameter(Config.FMT_LOCALIZATION_CONTEXT);
if (jstlInitParam != null) {
// Create a ResourceBundleMessageSource for the specified resource bundle
// basename in the JSTL context-param in web.xml, wiring it with the given
// Spring-defined MessageSource as parent.
ResourceBundleMessageSource jstlBundleWrapper = new ResourceBundleMessageSource();
jstlBundleWrapper.setBasename(jstlInitParam);
jstlBundleWrapper.setParentMessageSource(messageSource);
return jstlBundleWrapper;
}
}
return messageSource;
}
/**
* Exposes JSTL-specific request attributes specifying locale
* and resource bundle for JSTL's formatting and message tags,
* using Spring's locale and MessageSource.
* @param request the current HTTP request
* @param messageSource the MessageSource to expose,
* typically the current ApplicationContext (may be <code>null</code>)
* @see #exposeLocalizationContext(RequestContext)
*/
public static void exposeLocalizationContext(HttpServletRequest request, MessageSource messageSource) {
Locale jstlLocale = RequestContextUtils.getLocale(request);
Config.set(request, Config.FMT_LOCALE, jstlLocale);
if (messageSource != null) {
LocalizationContext jstlContext = new SpringLocalizationContext(messageSource, request);
Config.set(request, Config.FMT_LOCALIZATION_CONTEXT, jstlContext);
}
}
/**
* Exposes JSTL-specific request attributes specifying locale
* and resource bundle for JSTL's formatting and message tags,
* using Spring's locale and MessageSource.
* @param requestContext the context for the current HTTP request,
* including the ApplicationContext to expose as MessageSource
*/
public static void exposeLocalizationContext(RequestContext requestContext) {
Config.set(requestContext.getRequest(), Config.FMT_LOCALE, requestContext.getLocale());
MessageSource messageSource = getJstlAwareMessageSource(
requestContext.getServletContext(), requestContext.getMessageSource());
LocalizationContext jstlContext = new SpringLocalizationContext(messageSource, requestContext.getRequest());
Config.set(requestContext.getRequest(), Config.FMT_LOCALIZATION_CONTEXT, jstlContext);
}
/**
* Spring-specific LocalizationContext adapter that merges session-scoped
* JSTL LocalizationContext/Locale attributes with the local Spring request context.
*/
private static class SpringLocalizationContext extends LocalizationContext {
private final MessageSource messageSource;
private final HttpServletRequest request;
public SpringLocalizationContext(MessageSource messageSource, HttpServletRequest request) {
this.messageSource = messageSource;
this.request = request;
}
@Override
public ResourceBundle getResourceBundle() {
HttpSession session = this.request.getSession(false);
if (session != null) {
Object lcObject = Config.get(session, Config.FMT_LOCALIZATION_CONTEXT);
if (lcObject instanceof LocalizationContext) {
ResourceBundle lcBundle = ((LocalizationContext) lcObject).getResourceBundle();
return new MessageSourceResourceBundle(this.messageSource, getLocale(), lcBundle);
}
}
return new MessageSourceResourceBundle(this.messageSource, getLocale());
}
@Override
public Locale getLocale() {
HttpSession session = this.request.getSession(false);
if (session != null) {
Object localeObject = Config.get(session, Config.FMT_LOCALE);
if (localeObject instanceof Locale) {
return (Locale) localeObject;
}
}
return RequestContextUtils.getLocale(this.request);
}
};
}