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 java.util.concurrent.Callable; 020 021import org.springframework.core.MethodParameter; 022import org.springframework.lang.Nullable; 023import org.springframework.web.context.request.NativeWebRequest; 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 Callable}. 030 * 031 * @author Rossen Stoyanchev 032 * @since 3.2 033 */ 034public class CallableMethodReturnValueHandler implements HandlerMethodReturnValueHandler { 035 036 @Override 037 public boolean supportsReturnType(MethodParameter returnType) { 038 return Callable.class.isAssignableFrom(returnType.getParameterType()); 039 } 040 041 @Override 042 public void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, 043 ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception { 044 045 if (returnValue == null) { 046 mavContainer.setRequestHandled(true); 047 return; 048 } 049 050 Callable<?> callable = (Callable<?>) returnValue; 051 WebAsyncUtils.getAsyncManager(webRequest).startCallableProcessing(callable, mavContainer); 052 } 053 054}