001/* 002 * Copyright 2002-2015 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.bind.annotation; 018 019import java.lang.annotation.Documented; 020import java.lang.annotation.ElementType; 021import java.lang.annotation.Retention; 022import java.lang.annotation.RetentionPolicy; 023import java.lang.annotation.Target; 024 025import org.springframework.core.annotation.AliasFor; 026 027/** 028 * Annotation which indicates that a method parameter should be bound to a 029 * name-value pair within a path segment. Supported for {@link RequestMapping} 030 * annotated handler methods in Servlet environments. 031 * 032 * <p>If the method parameter type is {@link java.util.Map} and a matrix variable 033 * name is specified, then the matrix variable value is converted to a 034 * {@link java.util.Map} assuming an appropriate conversion strategy is available. 035 * 036 * <p>If the method parameter is {@link java.util.Map Map<String, String>} or 037 * {@link org.springframework.util.MultiValueMap MultiValueMap<String, String>} 038 * and a variable name is not specified, then the map is populated with all 039 * matrix variable names and values. 040 * 041 * @author Rossen Stoyanchev 042 * @author Sam Brannen 043 * @since 3.2 044 */ 045@Target(ElementType.PARAMETER) 046@Retention(RetentionPolicy.RUNTIME) 047@Documented 048public @interface MatrixVariable { 049 050 /** 051 * Alias for {@link #name}. 052 */ 053 @AliasFor("name") 054 String value() default ""; 055 056 /** 057 * The name of the matrix variable. 058 * @since 4.2 059 * @see #value 060 */ 061 @AliasFor("value") 062 String name() default ""; 063 064 /** 065 * The name of the URI path variable where the matrix variable is located, 066 * if necessary for disambiguation (e.g. a matrix variable with the same 067 * name present in more than one path segment). 068 */ 069 String pathVar() default ValueConstants.DEFAULT_NONE; 070 071 /** 072 * Whether the matrix variable is required. 073 * <p>Default is {@code true}, leading to an exception being thrown in 074 * case the variable is missing in the request. Switch this to {@code false} 075 * if you prefer a {@code null} if the variable is missing. 076 * <p>Alternatively, provide a {@link #defaultValue}, which implicitly sets 077 * this flag to {@code false}. 078 */ 079 boolean required() default true; 080 081 /** 082 * The default value to use as a fallback. 083 * <p>Supplying a default value implicitly sets {@link #required} to 084 * {@code false}. 085 */ 086 String defaultValue() default ValueConstants.DEFAULT_NONE; 087 088}