spring HandlerMethodReturnValueHandlerComposite 源码

spring HandlerMethodReturnValueHandlerComposite 代码

文件路径：/spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/HandlerMethodReturnValueHandlerComposite.java

/*
 * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.messaging.handler.invocation.reactive;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import reactor.core.publisher.Mono;

import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;

/**
 * A HandlerMethodReturnValueHandler that wraps and delegates to others.
 *
 * @author Rossen Stoyanchev
 * @since 5.2
 */
public class HandlerMethodReturnValueHandlerComposite implements HandlerMethodReturnValueHandler {

	protected final Log logger = LogFactory.getLog(getClass());

	private final List<HandlerMethodReturnValueHandler> returnValueHandlers = new ArrayList<>();


	/**
	 * Return a read-only list with the configured handlers.
	 */
	public List<HandlerMethodReturnValueHandler> getReturnValueHandlers() {
		return Collections.unmodifiableList(this.returnValueHandlers);
	}

	/**
	 * Clear the list of configured handlers.
	 */
	public void clear() {
		this.returnValueHandlers.clear();
	}

	/**
	 * Add the given {@link HandlerMethodReturnValueHandler}.
	 */
	public HandlerMethodReturnValueHandlerComposite addHandler(HandlerMethodReturnValueHandler returnValueHandler) {
		this.returnValueHandlers.add(returnValueHandler);
		return this;
	}

	/**
	 * Add the given {@link HandlerMethodReturnValueHandler HandlerMethodReturnValueHandlers}.
	 */
	public HandlerMethodReturnValueHandlerComposite addHandlers(
			@Nullable List<? extends HandlerMethodReturnValueHandler> handlers) {

		if (handlers != null) {
			this.returnValueHandlers.addAll(handlers);
		}
		return this;
	}

	@Override
	public boolean supportsReturnType(MethodParameter returnType) {
		return getReturnValueHandler(returnType) != null;
	}

	@Override
	public Mono<Void> handleReturnValue(@Nullable Object returnValue, MethodParameter returnType, Message<?> message) {
		HandlerMethodReturnValueHandler handler = getReturnValueHandler(returnType);
		if (handler == null) {
			throw new IllegalStateException("No handler for return value type: " + returnType.getParameterType());
		}
		if (logger.isTraceEnabled()) {
			logger.trace("Processing return value with " + handler);
		}
		return handler.handleReturnValue(returnValue, returnType, message);
	}

	@SuppressWarnings("ForLoopReplaceableByForEach")
	@Nullable
	private HandlerMethodReturnValueHandler getReturnValueHandler(MethodParameter returnType) {
		for (HandlerMethodReturnValueHandler handler : this.returnValueHandlers) {
			if (handler.supportsReturnType(returnType)) {
				return handler;
			}
		}
		return null;
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractEncoderMethodReturnValueHandler 源码

spring AbstractMethodMessageHandler 源码

spring ArgumentResolverConfigurer 源码

spring ChannelSendOperator 源码

spring HandlerMethodArgumentResolver 源码

spring HandlerMethodArgumentResolverComposite 源码

spring HandlerMethodReturnValueHandler 源码

spring InvocableHandlerMethod 源码

spring InvocableHelper 源码

spring ReturnValueHandlerConfigurer 源码