/*
* Copyright 2002-2011 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.mvc.method.annotation;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.MethodParameter;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.util.Assert;
import org.springframework.web.HttpMediaTypeNotSupportedException;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
/**
* A base class for resolving method argument values by reading from the body of a request
* with {@link HttpMessageConverter}s.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @since 3.1
*/
public abstract class AbstractMessageConverterMethodArgumentResolver implements HandlerMethodArgumentResolver {
protected final Log logger = LogFactory.getLog(getClass());
protected final List<HttpMessageConverter<?>> messageConverters;
protected final List<MediaType> allSupportedMediaTypes;
public AbstractMessageConverterMethodArgumentResolver(List<HttpMessageConverter<?>> messageConverters) {
Assert.notEmpty(messageConverters, "'messageConverters' must not be empty");
this.messageConverters = messageConverters;
this.allSupportedMediaTypes = getAllSupportedMediaTypes(messageConverters);
}
/**
* Returns the media types supported by all provided message converters preserving their ordering and
* further sorting by specificity via {@link MediaType#sortBySpecificity(List)}.
*/
private static List<MediaType> getAllSupportedMediaTypes(List<HttpMessageConverter<?>> messageConverters) {
Set<MediaType> allSupportedMediaTypes = new LinkedHashSet<MediaType>();
for (HttpMessageConverter<?> messageConverter : messageConverters) {
allSupportedMediaTypes.addAll(messageConverter.getSupportedMediaTypes());
}
List<MediaType> result = new ArrayList<MediaType>(allSupportedMediaTypes);
MediaType.sortBySpecificity(result);
return Collections.unmodifiableList(result);
}
/**
* Creates the method argument value of the expected parameter type by reading from the given request.
*
* @param <T> the expected type of the argument value to be created
* @param webRequest the current request
* @param methodParam the method argument
* @param paramType the type of the argument value to be created
* @return the created method argument value
* @throws IOException if the reading from the request fails
* @throws HttpMediaTypeNotSupportedException if no suitable message converter is found
*/
protected <T> Object readWithMessageConverters(NativeWebRequest webRequest, MethodParameter methodParam, Class<T> paramType) throws IOException,
HttpMediaTypeNotSupportedException {
HttpInputMessage inputMessage = createInputMessage(webRequest);
return readWithMessageConverters(inputMessage, methodParam, paramType);
}
/**
* Creates the method argument value of the expected parameter type by reading from the given HttpInputMessage.
*
* @param <T> the expected type of the argument value to be created
* @param inputMessage the HTTP input message representing the current request
* @param methodParam the method argument
* @param paramType the type of the argument value to be created
* @return the created method argument value
* @throws IOException if the reading from the request fails
* @throws HttpMediaTypeNotSupportedException if no suitable message converter is found
*/
@SuppressWarnings("unchecked")
protected <T> Object readWithMessageConverters(HttpInputMessage inputMessage, MethodParameter methodParam, Class<T> paramType) throws IOException,
HttpMediaTypeNotSupportedException {
MediaType contentType = inputMessage.getHeaders().getContentType();
if (contentType == null) {
contentType = MediaType.APPLICATION_OCTET_STREAM;
}
for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
if (messageConverter.canRead(paramType, contentType)) {
if (logger.isDebugEnabled()) {
logger.debug("Reading [" + paramType.getName() + "] as \"" + contentType + "\" using [" +
messageConverter + "]");
}
return ((HttpMessageConverter<T>) messageConverter).read(paramType, inputMessage);
}
}
throw new HttpMediaTypeNotSupportedException(contentType, allSupportedMediaTypes);
}
/**
* Creates a new {@link HttpInputMessage} from the given {@link NativeWebRequest}.
*
* @param webRequest the web request to create an input message from
* @return the input message
*/
protected ServletServerHttpRequest createInputMessage(NativeWebRequest webRequest) {
HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
return new ServletServerHttpRequest(servletRequest);
}
}