001/* 002 * Copyright 2002-2019 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.reactive; 018 019import reactor.core.publisher.Mono; 020 021import org.springframework.core.MethodParameter; 022import org.springframework.lang.Nullable; 023import org.springframework.messaging.Message; 024 025/** 026 * An extension of {@link HandlerMethodArgumentResolver} for implementations 027 * that are synchronous in nature and do not block to resolve values. 028 * 029 * @author Rossen Stoyanchev 030 * @since 5.2 031 */ 032public interface SyncHandlerMethodArgumentResolver extends HandlerMethodArgumentResolver { 033 034 /** 035 * {@inheritDoc} 036 * <p>By default this simply delegates to {@link #resolveArgumentValue} for 037 * synchronous resolution. 038 */ 039 @Override 040 default Mono<Object> resolveArgument(MethodParameter parameter, Message<?> message) { 041 return Mono.justOrEmpty(resolveArgumentValue(parameter, message)); 042 } 043 044 /** 045 * Resolve the value for the method parameter synchronously. 046 * @param parameter the method parameter 047 * @param message the currently processed message 048 * @return the resolved value, if any 049 */ 050 @Nullable 051 Object resolveArgumentValue(MethodParameter parameter, Message<?> message); 052 053}