001/* 002 * Copyright 2002-2016 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.condition; 018 019import javax.servlet.http.HttpServletRequest; 020 021import org.springframework.lang.Nullable; 022 023/** 024 * Contract for request mapping conditions. 025 * 026 * <p>Request conditions can be combined via {@link #combine(Object)}, matched to 027 * a request via {@link #getMatchingCondition(HttpServletRequest)}, and compared 028 * to each other via {@link #compareTo(Object, HttpServletRequest)} to determine 029 * which is a closer match for a given request. 030 * 031 * @author Rossen Stoyanchev 032 * @author Arjen Poutsma 033 * @since 3.1 034 * @param <T> the type of objects that this RequestCondition can be combined 035 * with and compared to 036 */ 037public interface RequestCondition<T> { 038 039 /** 040 * Combine this condition with another such as conditions from a 041 * type-level and method-level {@code @RequestMapping} annotation. 042 * @param other the condition to combine with. 043 * @return a request condition instance that is the result of combining 044 * the two condition instances. 045 */ 046 T combine(T other); 047 048 /** 049 * Check if the condition matches the request returning a potentially new 050 * instance created for the current request. For example a condition with 051 * multiple URL patterns may return a new instance only with those patterns 052 * that match the request. 053 * <p>For CORS pre-flight requests, conditions should match to the would-be, 054 * actual request (e.g. URL pattern, query parameters, and the HTTP method 055 * from the "Access-Control-Request-Method" header). If a condition cannot 056 * be matched to a pre-flight request it should return an instance with 057 * empty content thus not causing a failure to match. 058 * @return a condition instance in case of a match or {@code null} otherwise. 059 */ 060 @Nullable 061 T getMatchingCondition(HttpServletRequest request); 062 063 /** 064 * Compare this condition to another condition in the context of 065 * a specific request. This method assumes both instances have 066 * been obtained via {@link #getMatchingCondition(HttpServletRequest)} 067 * to ensure they have content relevant to current request only. 068 */ 069 int compareTo(T other, HttpServletRequest request); 070 071}