/*
 * Copyright 2002-2013 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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.LocaleResolver;

/**
 * {@link LocaleResolver} implementation that simply uses the primary locale
 * specified in the "accept-language" header of the HTTP request (that is,
 * the locale sent by the client browser, normally that of the client's OS).
 *
 * <p>Note: Does not support {@code setLocale}, since the accept header
 * can only be changed through changing the client's locale settings.
 *
 * @author Juergen Hoeller
 * @since 27.02.2003
 * @see javax.servlet.http.HttpServletRequest#getLocale()
 */
public class AcceptHeaderLocaleResolver implements LocaleResolver {

	@Override
	public Locale resolveLocale(HttpServletRequest request) {
		return request.getLocale();
	}

	@Override
	public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {
		throw new UnsupportedOperationException(
				"Cannot change HTTP accept header - use a different locale resolution strategy");
	}

}
