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.messaging.handler.invocation; 018 019import org.springframework.core.MethodParameter; 020import org.springframework.messaging.Message; 021 022/** 023 * Convenient base class for {@link AsyncHandlerMethodReturnValueHandler} 024 * implementations that support only asynchronous (Future-like) return values 025 * and merely serve as adapters of such types to Spring's 026 * {@link org.springframework.util.concurrent.ListenableFuture ListenableFuture}. 027 * 028 * @author Sebastien Deleuze 029 * @since 4.2 030 */ 031public abstract class AbstractAsyncReturnValueHandler implements AsyncHandlerMethodReturnValueHandler { 032 033 @Override 034 public boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType) { 035 return true; 036 } 037 038 @Override 039 public void handleReturnValue(Object returnValue, MethodParameter returnType, Message<?> message) { 040 // Should never be called since we return "true" from isAsyncReturnValue 041 throw new IllegalStateException("Unexpected invocation"); 042 } 043 044}