001/*
002 * Copyright 2002-2018 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.reactive.result.method;
018
019import reactor.core.publisher.Mono;
020
021import org.springframework.core.MethodParameter;
022import org.springframework.lang.Nullable;
023import org.springframework.web.reactive.BindingContext;
024import org.springframework.web.server.ServerWebExchange;
025
026/**
027 * An extension of {@link HandlerMethodArgumentResolver} for implementations
028 * that are synchronous in nature and do not block to resolve values.
029 *
030 * @author Rossen Stoyanchev
031 * @since 5.0
032 */
033public interface SyncHandlerMethodArgumentResolver extends HandlerMethodArgumentResolver {
034
035        /**
036         * {@inheritDoc}
037         * <p>By default this simply delegates to {@link #resolveArgumentValue} for
038         * synchronous resolution.
039         */
040        @Override
041        default Mono<Object> resolveArgument(
042                        MethodParameter parameter, BindingContext bindingContext, ServerWebExchange exchange) {
043
044                return Mono.justOrEmpty(resolveArgumentValue(parameter, bindingContext, exchange));
045        }
046
047        /**
048         * Resolve the value for the method parameter synchronously.
049         * @param parameter the method parameter
050         * @param bindingContext the binding context to use
051         * @param exchange the current exchange
052         * @return the resolved value, if any
053         */
054        @Nullable
055        Object resolveArgumentValue(
056                        MethodParameter parameter, BindingContext bindingContext, ServerWebExchange exchange);
057
058}