/*
* Copyright 2002-2012 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.accept;
import java.util.Collections;
import java.util.List;
import org.springframework.http.MediaType;
import org.springframework.util.StringUtils;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.context.request.NativeWebRequest;
/**
* A ContentNegotiationStrategy that parses the 'Accept' header of the request.
*
* @author Rossen Stoyanchev
* @since 3.2
*/
public class HeaderContentNegotiationStrategy implements ContentNegotiationStrategy {
private static final String ACCEPT_HEADER = "Accept";
/**
* {@inheritDoc}
* @throws HttpMediaTypeNotAcceptableException if the 'Accept' header cannot be parsed.
*/
public List<MediaType> resolveMediaTypes(NativeWebRequest webRequest) throws HttpMediaTypeNotAcceptableException {
String acceptHeader = webRequest.getHeader(ACCEPT_HEADER);
try {
if (StringUtils.hasText(acceptHeader)) {
List<MediaType> mediaTypes = MediaType.parseMediaTypes(acceptHeader);
MediaType.sortBySpecificityAndQuality(mediaTypes);
return mediaTypes;
}
}
catch (IllegalArgumentException ex) {
throw new HttpMediaTypeNotAcceptableException(
"Could not parse accept header [" + acceptHeader + "]: " + ex.getMessage());
}
return Collections.emptyList();
}
}