spring MatrixVariableMapMethodArgumentResolver 源码

spring MatrixVariableMapMethodArgumentResolver 代码

文件路径：/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/MatrixVariableMapMethodArgumentResolver.java

/*
 * Copyright 2002-2018 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.web.reactive.result.method.annotation;

import java.util.Collections;
import java.util.List;
import java.util.Map;

import org.springframework.core.MethodParameter;
import org.springframework.core.ReactiveAdapterRegistry;
import org.springframework.core.ResolvableType;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.MatrixVariable;
import org.springframework.web.bind.annotation.ValueConstants;
import org.springframework.web.reactive.BindingContext;
import org.springframework.web.reactive.HandlerMapping;
import org.springframework.web.reactive.result.method.HandlerMethodArgumentResolverSupport;
import org.springframework.web.reactive.result.method.SyncHandlerMethodArgumentResolver;
import org.springframework.web.server.ServerWebExchange;

/**
 * Resolves arguments of type {@link Map} annotated with {@link MatrixVariable @MatrixVariable}
 * where the annotation does not specify a name. In other words the purpose of this resolver
 * is to provide access to multiple matrix variables, either all or associated with a specific
 * path variable.
 *
 * <p>When a name is specified, an argument of type Map is considered to be a single attribute
 * with a Map value, and is resolved by {@link MatrixVariableMethodArgumentResolver} instead.
 *
 * @author Rossen Stoyanchev
 * @since 5.0.1
 * @see MatrixVariableMethodArgumentResolver
 */
public class MatrixVariableMapMethodArgumentResolver extends HandlerMethodArgumentResolverSupport
		implements SyncHandlerMethodArgumentResolver {

	public MatrixVariableMapMethodArgumentResolver(ReactiveAdapterRegistry registry) {
		super(registry);
	}


	@Override
	public boolean supportsParameter(MethodParameter parameter) {
		return checkAnnotatedParamNoReactiveWrapper(parameter, MatrixVariable.class,
				(ann, type) -> (Map.class.isAssignableFrom(type) && !StringUtils.hasText(ann.name())));
	}

	@Nullable
	@Override
	public Object resolveArgumentValue(MethodParameter parameter, BindingContext bindingContext,
			ServerWebExchange exchange) {

		Map<String, MultiValueMap<String, String>> matrixVariables =
				exchange.getAttribute(HandlerMapping.MATRIX_VARIABLES_ATTRIBUTE);

		if (CollectionUtils.isEmpty(matrixVariables)) {
			return Collections.emptyMap();
		}

		MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
		MatrixVariable annotation = parameter.getParameterAnnotation(MatrixVariable.class);
		Assert.state(annotation != null, "No MatrixVariable annotation");
		String pathVariable = annotation.pathVar();

		if (!pathVariable.equals(ValueConstants.DEFAULT_NONE)) {
			MultiValueMap<String, String> mapForPathVariable = matrixVariables.get(pathVariable);
			if (mapForPathVariable == null) {
				return Collections.emptyMap();
			}
			map.putAll(mapForPathVariable);
		}
		else {
			for (MultiValueMap<String, String> vars : matrixVariables.values()) {
				vars.forEach((name, values) -> {
					for (String value : values) {
						map.add(name, value);
					}
				});
			}
		}

		return (isSingleValueMap(parameter) ? map.toSingleValueMap() : map);
	}

	private boolean isSingleValueMap(MethodParameter parameter) {
		if (!MultiValueMap.class.isAssignableFrom(parameter.getParameterType())) {
			ResolvableType[] genericTypes = ResolvableType.forMethodParameter(parameter).getGenerics();
			if (genericTypes.length == 2) {
				return !List.class.isAssignableFrom(genericTypes[1].toClass());
			}
		}
		return false;
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractMessageReaderArgumentResolver 源码

spring AbstractMessageWriterResultHandler 源码

spring AbstractNamedValueArgumentResolver 源码

spring AbstractNamedValueSyncArgumentResolver 源码

spring ArgumentResolverConfigurer 源码

spring ContinuationHandlerMethodArgumentResolver 源码

spring ControllerMethodResolver 源码

spring CookieValueMethodArgumentResolver 源码

spring ErrorsMethodArgumentResolver 源码

spring ExpressionValueMethodArgumentResolver 源码