org.cloudfoundry.identity.uaa.config.HandlerAdapterFactoryBean.java Source code

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Here is the source code for org.cloudfoundry.identity.uaa.config.HandlerAdapterFactoryBean.java

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/*
 * Cloud Foundry 2012.02.03 Beta
 * Copyright (c) [2009-2012] VMware, Inc. All Rights Reserved.
 *
 * This product is licensed to you under the Apache License, Version 2.0 (the "License").
 * You may not use this product except in compliance with the License.
 *
 * This product includes a number of subcomponents with
 * separate copyright notices and license terms. Your use of these
 * subcomponents is subject to the terms and conditions of the
 * subcomponent's license, as noted in the LICENSE file.
 */
package org.cloudfoundry.identity.uaa.config;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.cloudfoundry.identity.uaa.scim.ScimCore;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.MethodParameter;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.ModelAndViewContainer;
import org.springframework.web.servlet.HandlerAdapter;
import org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor;

/**
 * Factory for a handler adapter that sniffs the results from {@link RequestMapping} method executions and adds an ETag
 * header if the result is a {@link ScimCore}. Inject into application context as anonymous bean.
 * 
 * @author Dave Syer
 * 
 */
public class HandlerAdapterFactoryBean implements FactoryBean<HandlerAdapter>, ApplicationContextAware {

    private ApplicationContext applicationContext;

    @Override
    public HandlerAdapter getObject() throws Exception {
        RequestMappingHandlerAdapter adapter = new RequestMappingHandlerAdapter();
        adapter.setApplicationContext(applicationContext);
        adapter.setMessageConverters(getMessageConverters());
        adapter.setOrder(0);
        adapter.setReturnValueHandlers(Arrays.<HandlerMethodReturnValueHandler>asList(
                new ScimEtagHandlerMethodReturnValueHandler(getMessageConverters())));
        adapter.afterPropertiesSet();
        return adapter;
    }

    private List<HttpMessageConverter<?>> getMessageConverters() {
        return new RestTemplate().getMessageConverters();
    }

    @Override
    public Class<?> getObjectType() {
        return AnnotationMethodHandlerAdapter.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }

    private static class ScimEtagHandlerMethodReturnValueHandler extends RequestResponseBodyMethodProcessor {

        public ScimEtagHandlerMethodReturnValueHandler(List<HttpMessageConverter<?>> messageConverters) {
            super(messageConverters);
        }

        @Override
        public boolean supportsReturnType(MethodParameter returnType) {
            return ScimCore.class.isAssignableFrom(returnType.getMethod().getReturnType());
        }

        @Override
        public void handleReturnValue(Object returnValue, MethodParameter returnType,
                ModelAndViewContainer mavContainer, NativeWebRequest webRequest)
                throws IOException, HttpMediaTypeNotAcceptableException {
            if (returnValue instanceof ScimCore) {
                HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);
                response.addHeader("ETag", "\"" + ((ScimCore) returnValue).getVersion() + "\"");
            }
            super.handleReturnValue(returnValue, returnType, mavContainer, webRequest);
        }

    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }
}