AbstractNotificationMessageHandlerMethodArgumentResolver.java

/*
 * Copyright 2013-2014 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.cloud.aws.messaging.endpoint;

import com.fasterxml.jackson.databind.JsonNode;
import org.springframework.core.MethodParameter;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.util.Assert;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * @author Agim Emruli
 */
public abstract class AbstractNotificationMessageHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {

    private static final String NOTIFICATION_REQUEST_ATTRIBUTE_NAME = "NOTIFICATION_REQUEST";
    private final MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();


    @SuppressWarnings("unchecked")
    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
                                  NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
        Assert.notNull(parameter, "Parameter must not be null");
        if (webRequest.getAttribute(NOTIFICATION_REQUEST_ATTRIBUTE_NAME, RequestAttributes.SCOPE_REQUEST) == null) {
            webRequest.setAttribute(NOTIFICATION_REQUEST_ATTRIBUTE_NAME, this.messageConverter.read(JsonNode.class,
                    createInputMessage(webRequest)), RequestAttributes.SCOPE_REQUEST);
        }

        JsonNode content = (JsonNode) webRequest.getAttribute(NOTIFICATION_REQUEST_ATTRIBUTE_NAME, RequestAttributes.SCOPE_REQUEST);
        return doResolveArgumentFromNotificationMessage(content, createInputMessage(webRequest), parameter.getParameterType());
    }

    protected abstract Object doResolveArgumentFromNotificationMessage(JsonNode content, HttpInputMessage request, Class<?> parameterType);

    private HttpInputMessage createInputMessage(NativeWebRequest webRequest) throws IOException {
        HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
        return new ServletServerHttpRequest(servletRequest);
    }
}