001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.servlet.mvc.method.annotation; 018 019import org.springframework.beans.factory.BeanFactory; 020import org.springframework.core.MethodParameter; 021import org.springframework.lang.Nullable; 022import org.springframework.web.context.request.NativeWebRequest; 023import org.springframework.web.context.request.async.WebAsyncTask; 024import org.springframework.web.context.request.async.WebAsyncUtils; 025import org.springframework.web.method.support.HandlerMethodReturnValueHandler; 026import org.springframework.web.method.support.ModelAndViewContainer; 027 028/** 029 * Handles return values of type {@link WebAsyncTask}. 030 * 031 * @author Rossen Stoyanchev 032 * @since 3.2 033 */ 034public class AsyncTaskMethodReturnValueHandler implements HandlerMethodReturnValueHandler { 035 036 @Nullable 037 private final BeanFactory beanFactory; 038 039 040 public AsyncTaskMethodReturnValueHandler(@Nullable BeanFactory beanFactory) { 041 this.beanFactory = beanFactory; 042 } 043 044 045 @Override 046 public boolean supportsReturnType(MethodParameter returnType) { 047 return WebAsyncTask.class.isAssignableFrom(returnType.getParameterType()); 048 } 049 050 @Override 051 public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, 052 ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception { 053 054 if (returnValue == null) { 055 mavContainer.setRequestHandled(true); 056 return; 057 } 058 059 WebAsyncTask<?> webAsyncTask = (WebAsyncTask<?>) returnValue; 060 if (this.beanFactory != null) { 061 webAsyncTask.setBeanFactory(this.beanFactory); 062 } 063 WebAsyncUtils.getAsyncManager(webRequest).startCallableProcessing(webAsyncTask, mavContainer); 064 } 065 066}