spring HandlerMethodArgumentResolverComposite 源码

spring HandlerMethodArgumentResolverComposite 代码

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

/*
 * Copyright 2002-2022 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;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

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

/**
 * Resolves method parameters by delegating to a list of registered
 * {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}.
 * Previously resolved method parameters are cached for faster lookups.
 *
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @since 4.0
 */
public class HandlerMethodArgumentResolverComposite implements HandlerMethodArgumentResolver {

	private final List<HandlerMethodArgumentResolver> argumentResolvers = new ArrayList<>();

	private final Map<MethodParameter, HandlerMethodArgumentResolver> argumentResolverCache =
			new ConcurrentHashMap<>(256);


	/**
	 * Add the given {@link HandlerMethodArgumentResolver}.
	 */
	public HandlerMethodArgumentResolverComposite addResolver(HandlerMethodArgumentResolver resolver) {
		this.argumentResolvers.add(resolver);
		return this;
	}

	/**
	 * Add the given {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}.
	 * @since 4.3
	 */
	public HandlerMethodArgumentResolverComposite addResolvers(
			@Nullable HandlerMethodArgumentResolver... resolvers) {

		if (resolvers != null) {
			Collections.addAll(this.argumentResolvers, resolvers);
		}
		return this;
	}

	/**
	 * Add the given {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}.
	 */
	public HandlerMethodArgumentResolverComposite addResolvers(
			@Nullable List<? extends HandlerMethodArgumentResolver> resolvers) {

		if (resolvers != null) {
			this.argumentResolvers.addAll(resolvers);
		}
		return this;
	}

	/**
	 * Return a read-only list with the contained resolvers, or an empty list.
	 */
	public List<HandlerMethodArgumentResolver> getResolvers() {
		return Collections.unmodifiableList(this.argumentResolvers);
	}

	/**
	 * Clear the list of configured resolvers and the resolver cache.
	 */
	public void clear() {
		this.argumentResolvers.clear();
		this.argumentResolverCache.clear();
	}


	/**
	 * Whether the given {@linkplain MethodParameter method parameter} is
	 * supported by any registered {@link HandlerMethodArgumentResolver}.
	 */
	@Override
	public boolean supportsParameter(MethodParameter parameter) {
		return getArgumentResolver(parameter) != null;
	}

	/**
	 * Iterate over registered
	 * {@link HandlerMethodArgumentResolver HandlerMethodArgumentResolvers}
	 * and invoke the one that supports it.
	 * @throws IllegalArgumentException if no suitable argument resolver is found
	 */
	@Override
	@Nullable
	public Object resolveArgument(MethodParameter parameter, Message<?> message) throws Exception {
		HandlerMethodArgumentResolver resolver = getArgumentResolver(parameter);
		if (resolver == null) {
			throw new IllegalArgumentException("Unsupported parameter type [" +
					parameter.getParameterType().getName() + "]. supportsParameter should be called first.");
		}
		return resolver.resolveArgument(parameter, message);
	}

	/**
	 * Find a registered {@link HandlerMethodArgumentResolver} that supports
	 * the given method parameter.
	 */
	@Nullable
	private HandlerMethodArgumentResolver getArgumentResolver(MethodParameter parameter) {
		HandlerMethodArgumentResolver result = this.argumentResolverCache.get(parameter);
		if (result == null) {
			for (HandlerMethodArgumentResolver resolver : this.argumentResolvers) {
				if (resolver.supportsParameter(parameter)) {
					result = resolver;
					this.argumentResolverCache.put(parameter, result);
					break;
				}
			}
		}
		return result;
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractAsyncReturnValueHandler 源码

spring AbstractExceptionHandlerMethodResolver 源码

spring AbstractMethodMessageHandler 源码

spring AsyncHandlerMethodReturnValueHandler 源码

spring CompletableFutureReturnValueHandler 源码

spring HandlerMethodArgumentResolver 源码

spring HandlerMethodReturnValueHandler 源码

spring HandlerMethodReturnValueHandlerComposite 源码

spring InvocableHandlerMethod 源码

spring ListenableFutureReturnValueHandler 源码