/*
 * Copyright 2002-2017 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
 *
 *      https://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.lang.reflect.Type;

import com.fasterxml.jackson.annotation.JsonView;

import org.springframework.core.MethodParameter;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter;
import org.springframework.http.converter.json.MappingJacksonInputMessage;
import org.springframework.util.Assert;

A RequestBodyAdvice implementation that adds support for Jackson's @JsonView annotation declared on a Spring MVC @HttpEntity or @RequestBody method parameter. 
The deserialization view specified in the annotation will be passed in to the MappingJackson2HttpMessageConverter which will then use it to deserialize the request body with. 
Note that despite @JsonView allowing for more than one class to be specified, the use for a request body advice is only supported with exactly one class argument. Consider the use of a composite interface. 
Author:
Sebastien Deleuze
See Also:
JsonView
readerWithView.readerWithView(Class)
Since:
4.2/**
 * A {@link RequestBodyAdvice} implementation that adds support for Jackson's
 * {@code @JsonView} annotation declared on a Spring MVC {@code @HttpEntity}
 * or {@code @RequestBody} method parameter.
 *
 * <p>The deserialization view specified in the annotation will be passed in to the
 * {@link org.springframework.http.converter.json.MappingJackson2HttpMessageConverter}
 * which will then use it to deserialize the request body with.
 *
 * <p>Note that despite {@code @JsonView} allowing for more than one class to
 * be specified, the use for a request body advice is only supported with
 * exactly one class argument. Consider the use of a composite interface.
 *
 * @author Sebastien Deleuze
 * @since 4.2
 * @see com.fasterxml.jackson.annotation.JsonView
 * @see com.fasterxml.jackson.databind.ObjectMapper#readerWithView(Class)
 */
public class JsonViewRequestBodyAdvice extends RequestBodyAdviceAdapter {

	@Override
	public boolean supports(MethodParameter methodParameter, Type targetType,
			Class<? extends HttpMessageConverter<?>> converterType) {

		return (AbstractJackson2HttpMessageConverter.class.isAssignableFrom(converterType) &&
				methodParameter.getParameterAnnotation(JsonView.class) != null);
	}

	@Override
	public HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter methodParameter,
			Type targetType, Class<? extends HttpMessageConverter<?>> selectedConverterType) throws IOException {

		JsonView ann = methodParameter.getParameterAnnotation(JsonView.class);
		Assert.state(ann != null, "No JsonView annotation");

		Class<?>[] classes = ann.value();
		if (classes.length != 1) {
			throw new IllegalArgumentException(
					"@JsonView only supported for request body advice with exactly 1 class argument: " + methodParameter);
		}

		return new MappingJacksonInputMessage(inputMessage.getBody(), inputMessage.getHeaders(), classes[0]);
	}

}