001/*
002 * Copyright 2002-2015 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.web.context.request.NativeWebRequest;
023import org.springframework.web.context.request.async.WebAsyncUtils;
024import org.springframework.web.method.support.AsyncHandlerMethodReturnValueHandler;
025import org.springframework.web.method.support.ModelAndViewContainer;
026
027/**
028 * Handles return values of type {@link Callable}.
029 *
030 * @author Rossen Stoyanchev
031 * @since 3.2
032 */
033public class CallableMethodReturnValueHandler implements AsyncHandlerMethodReturnValueHandler {
034
035        @Override
036        public boolean supportsReturnType(MethodParameter returnType) {
037                return Callable.class.isAssignableFrom(returnType.getParameterType());
038        }
039
040        @Override
041        public boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType) {
042                return (returnValue != null && returnValue instanceof Callable);
043        }
044
045        @Override
046        public void handleReturnValue(Object returnValue, MethodParameter returnType,
047                        ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
048
049                if (returnValue == null) {
050                        mavContainer.setRequestHandled(true);
051                        return;
052                }
053
054                Callable<?> callable = (Callable<?>) returnValue;
055                WebAsyncUtils.getAsyncManager(webRequest).startCallableProcessing(callable, mavContainer);
056        }
057
058}