ServiceMethodInfoHandlerMapping.java

/**
 * Copyright 2013-2014 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
 *
 *      http://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 com.iflytek.edu.cloud.frame.spring.rest;

import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerMapping;
import org.springframework.web.servlet.handler.AbstractHandlerMethodMapping;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;

abstract public class ServiceMethodInfoHandlerMapping extends AbstractHandlerMethodMapping<ServiceMethodInfo> {

	/**
	 * Get the URL path patterns associated with this {@link RequestMappingInfo}.
	 */
	@Override
	protected Set<String> getMappingPathPatterns(ServiceMethodInfo info) {
		HashSet<String> set = new HashSet<String>();
		set.add(info.getServiceMethodCondition().getMethod());
		return set;
	}

	/**
	 * Check if the given RequestMappingInfo matches the current request and
	 * return a (potentially new) instance with conditions that match the
	 * current request -- for example with a subset of URL patterns.
	 * @return an info in case of a match; or {@code null} otherwise.
	 */
	@Override
	protected ServiceMethodInfo getMatchingMapping(ServiceMethodInfo info, HttpServletRequest request) {
		return info.getMatchingCondition(request);
	}

	/**
	 * Provide a Comparator to sort RequestMappingInfos matched to a request.
	 */
	@Override
	protected Comparator<ServiceMethodInfo> getMappingComparator(final HttpServletRequest request) {
		return new Comparator<ServiceMethodInfo>() {
			@Override
			public int compare(ServiceMethodInfo info1, ServiceMethodInfo info2) {
				return info1.compareTo(info2, request);
			}
		};
	}

	/**
	 * Expose URI template variables, matrix variables, and producible media types in the request.
	 * @see HandlerMapping#URI_TEMPLATE_VARIABLES_ATTRIBUTE
	 * @see HandlerMapping#MATRIX_VARIABLES_ATTRIBUTE
	 * @see HandlerMapping#PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE
	 */
	@Override
	protected void handleMatch(ServiceMethodInfo info, String lookupPath, HttpServletRequest request) {
		super.handleMatch(info, lookupPath, request);
		request.setAttribute(BEST_MATCHING_PATTERN_ATTRIBUTE, lookupPath);
		request.setAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, Collections.emptyMap());
	}

	/**
	 * Iterate all RequestMappingInfos once again, look if any match by URL at
	 * least and raise exceptions accordingly.
	 * @throws HttpRequestMethodNotSupportedException if there are matches by URL
	 * but not by HTTP method
	 * @throws HttpMediaTypeNotAcceptableException if there are matches by URL
	 * but not by consumable/producible media types
	 */
	@Override
	protected HandlerMethod handleNoMatch(Set<ServiceMethodInfo> requestMappingInfos,
			String lookupPath, HttpServletRequest request) throws ServletException {

		Set<String> allowedMethods = new LinkedHashSet<String>(4);

		Set<ServiceMethodInfo> patternMatches = new HashSet<ServiceMethodInfo>();
		Set<ServiceMethodInfo> patternAndMethodMatches = new HashSet<ServiceMethodInfo>();

		for (ServiceMethodInfo info : requestMappingInfos) {
			if (info.getServiceMethodCondition().getMatchingCondition(request) != null) {
				patternMatches.add(info);
				if (info.getMethodsCondition().getMatchingCondition(request) != null) {
					patternAndMethodMatches.add(info);
				}
				else {
					for (RequestMethod method : info.getMethodsCondition().getMethods()) {
						allowedMethods.add(method.name());
					}
				}
			}
		}

		if (patternMatches.isEmpty()) {
			return null;
		} else if (patternAndMethodMatches.isEmpty() && !allowedMethods.isEmpty()) {
			throw new HttpRequestMethodNotSupportedException(request.getMethod(), allowedMethods);
		} else {
			return null;
		}
	}

}