001/*
002 * Copyright 2002-2017 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.servlet.mvc.method.annotation;
018
019import java.util.Collections;
020import java.util.LinkedHashMap;
021import java.util.Map;
022
023import org.springframework.core.MethodParameter;
024import org.springframework.lang.Nullable;
025import org.springframework.util.CollectionUtils;
026import org.springframework.util.StringUtils;
027import org.springframework.web.bind.annotation.PathVariable;
028import org.springframework.web.bind.support.WebDataBinderFactory;
029import org.springframework.web.context.request.NativeWebRequest;
030import org.springframework.web.context.request.RequestAttributes;
031import org.springframework.web.method.support.HandlerMethodArgumentResolver;
032import org.springframework.web.method.support.ModelAndViewContainer;
033import org.springframework.web.servlet.HandlerMapping;
034
035/**
036 * Resolves {@link Map} method arguments annotated with an @{@link PathVariable}
037 * where the annotation does not specify a path variable name. The created
038 * {@link Map} contains all URI template name/value pairs.
039 *
040 * @author Rossen Stoyanchev
041 * @since 3.2
042 * @see PathVariableMethodArgumentResolver
043 */
044public class PathVariableMapMethodArgumentResolver implements HandlerMethodArgumentResolver {
045
046        @Override
047        public boolean supportsParameter(MethodParameter parameter) {
048                PathVariable ann = parameter.getParameterAnnotation(PathVariable.class);
049                return (ann != null && Map.class.isAssignableFrom(parameter.getParameterType()) &&
050                                !StringUtils.hasText(ann.value()));
051        }
052
053        /**
054         * Return a Map with all URI template variables or an empty map.
055         */
056        @Override
057        public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
058                        NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
059
060                @SuppressWarnings("unchecked")
061                Map<String, String> uriTemplateVars =
062                                (Map<String, String>) webRequest.getAttribute(
063                                                HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
064
065                if (!CollectionUtils.isEmpty(uriTemplateVars)) {
066                        return new LinkedHashMap<>(uriTemplateVars);
067                }
068                else {
069                        return Collections.emptyMap();
070                }
071        }
072
073}