/*
* 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.i18n;
import java.util.Locale;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.util.CookieGenerator;
import org.springframework.web.util.WebUtils;
/**
* {@link LocaleResolver} implementation that uses a cookie sent back to the user
* in case of a custom setting, with a fallback to the specified default locale
* or the request's accept-header locale.
*
* <p>This is particularly useful for stateless applications without user sessions.
*
* <p>Custom controllers can thus override the user's locale by calling
* {@link #setLocale(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.util.Locale)},
* for example responding to a certain locale change request.
*
* @author Juergen Hoeller
* @author Jean-Pierre Pawlak
* @since 27.02.2003
* @see #setDefaultLocale
* @see #setLocale
*/
public class CookieLocaleResolver extends CookieGenerator implements LocaleResolver {
/**
* The name of the request attribute that holds the locale.
* <p>Only used for overriding a cookie value if the locale has been
* changed in the course of the current request! Use
* {@link org.springframework.web.servlet.support.RequestContext#getLocale}
* to retrieve the current locale in controllers or views.
* @see org.springframework.web.servlet.support.RequestContext#getLocale
*/
public static final String LOCALE_REQUEST_ATTRIBUTE_NAME = CookieLocaleResolver.class.getName() + ".LOCALE";
/**
* The default cookie name used if none is explicitly set.
*/
public static final String DEFAULT_COOKIE_NAME = CookieLocaleResolver.class.getName() + ".LOCALE";
private Locale defaultLocale;
/**
* Creates a new instance of the {@link CookieLocaleResolver} class
* using the {@link #DEFAULT_COOKIE_NAME default cookie name}.
*/
public CookieLocaleResolver() {
setCookieName(DEFAULT_COOKIE_NAME);
}
/**
* Set a fixed Locale that this resolver will return if no cookie found.
*/
public void setDefaultLocale(Locale defaultLocale) {
this.defaultLocale = defaultLocale;
}
/**
* Return the fixed Locale that this resolver will return if no cookie found,
* if any.
*/
protected Locale getDefaultLocale() {
return this.defaultLocale;
}
public Locale resolveLocale(HttpServletRequest request) {
// Check request for pre-parsed or preset locale.
Locale locale = (Locale) request.getAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME);
if (locale != null) {
return locale;
}
// Retrieve and parse cookie value.
Cookie cookie = WebUtils.getCookie(request, getCookieName());
if (cookie != null) {
locale = StringUtils.parseLocaleString(cookie.getValue());
if (logger.isDebugEnabled()) {
logger.debug("Parsed cookie value [" + cookie.getValue() + "] into locale '" + locale + "'");
}
if (locale != null) {
request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, locale);
return locale;
}
}
return determineDefaultLocale(request);
}
public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {
if (locale != null) {
// Set request attribute and add cookie.
request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, locale);
addCookie(response, locale.toString());
}
else {
// Set request attribute to fallback locale and remove cookie.
request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, determineDefaultLocale(request));
removeCookie(response);
}
}
/**
* Determine the default locale for the given request,
* Called if no locale cookie has been found.
* <p>The default implementation returns the specified default locale,
* if any, else falls back to the request's accept-header locale.
* @param request the request to resolve the locale for
* @return the default locale (never <code>null</code>)
* @see #setDefaultLocale
* @see javax.servlet.http.HttpServletRequest#getLocale()
*/
protected Locale determineDefaultLocale(HttpServletRequest request) {
Locale defaultLocale = getDefaultLocale();
if (defaultLocale == null) {
defaultLocale = request.getLocale();
}
return defaultLocale;
}
}
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