001/* 002 * Copyright 2002-2016 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; 018 019import java.util.function.Function; 020 021import reactor.core.publisher.Mono; 022 023import org.springframework.web.server.ServerWebExchange; 024 025/** 026 * Contract that decouples the {@link DispatcherHandler} from the details of 027 * invoking a handler and makes it possible to support any handler type. 028 * 029 * @author Rossen Stoyanchev 030 * @author Sebastien Deleuze 031 * @since 5.0 032 */ 033public interface HandlerAdapter { 034 035 /** 036 * Whether this {@code HandlerAdapter} supports the given {@code handler}. 037 * @param handler the handler object to check 038 * @return whether or not the handler is supported 039 */ 040 boolean supports(Object handler); 041 042 /** 043 * Handle the request with the given handler. 044 * <p>Implementations are encouraged to handle exceptions resulting from the 045 * invocation of a handler in order and if necessary to return an alternate 046 * result that represents an error response. 047 * <p>Furthermore since an async {@code HandlerResult} may produce an error 048 * later during result handling implementations are also encouraged to 049 * {@link HandlerResult#setExceptionHandler(Function) set an exception 050 * handler} on the {@code HandlerResult} so that may also be applied later 051 * after result handling. 052 * @param exchange current server exchange 053 * @param handler the selected handler which must have been previously 054 * checked via {@link #supports(Object)} 055 * @return {@link Mono} that emits a single {@code HandlerResult} or none if 056 * the request has been fully handled and doesn't require further handling. 057 */ 058 Mono<HandlerResult> handle(ServerWebExchange exchange, Object handler); 059 060}