Spring Framework example source code file (RequestContextUtils.java)

This example Spring Framework source code file (RequestContextUtils.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

dispatcherservlet, http, illegalstateexception, illegalstateexception, localeresolver, localeresolver, no, request, requestcontextutils, response, servlet, servletrequest, string, themeresolver, themeresolver, themesource, util, webapplicationcontext, webapplicationcontext

The Spring Framework RequestContextUtils.java source code

/*
 * Copyright 2002-2007 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 javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

import org.springframework.ui.context.Theme;
import org.springframework.ui.context.ThemeSource;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.servlet.DispatcherServlet;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.ThemeResolver;

/**
 * Utility class for easy access to request-specific state which has been
 * set by the {@link org.springframework.web.servlet.DispatcherServlet}.
 *
 * <p>Supports lookup of current WebApplicationContext, LocaleResolver,
 * Locale, ThemeResolver, Theme, and MultipartResolver.
 *
 * @author Juergen Hoeller
 * @since 03.03.2003
 * @see RequestContext
 * @see org.springframework.web.servlet.DispatcherServlet
 */
public abstract class RequestContextUtils {

	/**
	 * Look for the WebApplicationContext associated with the DispatcherServlet
	 * that has initiated request processing.
	 * @param request current HTTP request
	 * @return the request-specific web application context
	 * @throws IllegalStateException if no servlet-specific context has been found
	 */
	public static WebApplicationContext getWebApplicationContext(ServletRequest request)
	    throws IllegalStateException {

		return getWebApplicationContext(request, null);
	}

	/**
	 * Look for the WebApplicationContext associated with the DispatcherServlet
	 * that has initiated request processing, and for the global context if none
	 * was found associated with the current request. This method is useful to
	 * allow components outside the framework, such as JSP tag handlers,
	 * to access the most specific application context available.
	 * @param request current HTTP request
	 * @param servletContext current servlet context
	 * @return the request-specific WebApplicationContext, or the global one
	 * if no request-specific context has been found
	 * @throws IllegalStateException if neither a servlet-specific nor a
	 * global context has been found
	 */
	public static WebApplicationContext getWebApplicationContext(
			ServletRequest request, ServletContext servletContext) throws IllegalStateException {

		WebApplicationContext webApplicationContext = (WebApplicationContext) request.getAttribute(
				DispatcherServlet.WEB_APPLICATION_CONTEXT_ATTRIBUTE);
		if (webApplicationContext == null) {
			if (servletContext == null) {
				throw new IllegalStateException("No WebApplicationContext found: not in a DispatcherServlet request?");
			}
			webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext);
			if (webApplicationContext == null) {
				throw new IllegalStateException("No WebApplicationContext found: no ContextLoaderListener registered?");
			}
		}
		return webApplicationContext;
	}

	/**
	 * Return the LocaleResolver that has been bound to the request by the
	 * DispatcherServlet.
	 * @param request current HTTP request
	 * @return the current LocaleResolver, or <code>null if not found
	 */
	public static LocaleResolver getLocaleResolver(HttpServletRequest request) {
		return (LocaleResolver) request.getAttribute(DispatcherServlet.LOCALE_RESOLVER_ATTRIBUTE);
	}

	/**
	 * Retrieves the current locale from the given request,
	 * using the LocaleResolver bound to the request by the DispatcherServlet
	 * (if available), falling back to the request's accept-header Locale.
	 * @param request current HTTP request
	 * @return the current locale, either from the LocaleResolver or from
	 * the plain request
	 * @see #getLocaleResolver
	 * @see javax.servlet.http.HttpServletRequest#getLocale()
	 */
	public static Locale getLocale(HttpServletRequest request) {
		LocaleResolver localeResolver = getLocaleResolver(request);
		if (localeResolver != null) {
			return localeResolver.resolveLocale(request);
		}
		else {
			return request.getLocale();
		}
	}

	/**
	 * Return the ThemeResolver that has been bound to the request by the
	 * DispatcherServlet.
	 * @param request current HTTP request
	 * @return the current ThemeResolver, or <code>null if not found
	 */
	public static ThemeResolver getThemeResolver(HttpServletRequest request) {
		return (ThemeResolver) request.getAttribute(DispatcherServlet.THEME_RESOLVER_ATTRIBUTE);
	}

	/**
	 * Return the ThemeSource that has been bound to the request by the
	 * DispatcherServlet.
	 * @param request current HTTP request
	 * @return the current ThemeSource
	 */
	public static ThemeSource getThemeSource(HttpServletRequest request) {
		return (ThemeSource) request.getAttribute(DispatcherServlet.THEME_SOURCE_ATTRIBUTE);
	}

	/**
	 * Retrieves the current theme from the given request, using the ThemeResolver
	 * and ThemeSource bound to the request by the DispatcherServlet.
	 * @param request current HTTP request
	 * @return the current theme, or <code>null if not found
	 * @see #getThemeResolver
	 */
	public static Theme getTheme(HttpServletRequest request) {
		ThemeResolver themeResolver = getThemeResolver(request);
		ThemeSource themeSource = getThemeSource(request);
		if (themeResolver != null && themeSource != null) {
			String themeName = themeResolver.resolveThemeName(request);
			return themeSource.getTheme(themeName);
		}
		else {
			return null;
		}
	}

}