1 /* 2 * Copyright 2009-2024 the original author or authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * https://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package org.apache.ibatis.annotations; 17 18 import java.lang.annotation.Documented; 19 import java.lang.annotation.ElementType; 20 import java.lang.annotation.Retention; 21 import java.lang.annotation.RetentionPolicy; 22 import java.lang.annotation.Target; 23 24 import org.apache.ibatis.type.JdbcType; 25 import org.apache.ibatis.type.TypeHandler; 26 import org.apache.ibatis.type.UnknownTypeHandler; 27 28 /** 29 * The annotation that be grouping conditional mapping definitions. 30 * <p> 31 * <b>How to use:</b> 32 * 33 * <pre>{@code 34 * public interface UserMapper { 35 * @Select("SELECT id, name, type FROM users ORDER BY id") 36 * @TypeDiscriminator(column = "type", javaType = String.class, cases = { 37 * @Case(value = "1", type = PremiumUser.class), @Case(value = "2", type = GeneralUser.class), 38 * @Case(value = "3", type = TemporaryUser.class) }) 39 * List<User> selectAll(); 40 * } 41 * }</pre> 42 * 43 * @author Clinton Begin 44 */ 45 @Documented 46 @Retention(RetentionPolicy.RUNTIME) 47 @Target(ElementType.METHOD) 48 public @interface TypeDiscriminator { 49 50 /** 51 * Returns the column name(column label) that hold conditional value. 52 * 53 * @return the column name(column label) 54 */ 55 String column(); 56 57 /** 58 * Return the java type for conditional value. 59 * 60 * @return the java type 61 */ 62 Class<?> javaType() default void.class; 63 64 /** 65 * Return the jdbc type for column that hold conditional value. 66 * 67 * @return the jdbc type 68 */ 69 JdbcType jdbcType() default JdbcType.UNDEFINED; 70 71 /** 72 * Returns the {@link TypeHandler} type for retrieving a column value from result set. 73 * 74 * @return the {@link TypeHandler} type 75 */ 76 Class<? extends TypeHandler> typeHandler() default UnknownTypeHandler.class; 77 78 /** 79 * Returns conditional mapping definitions. 80 * 81 * @return conditional mapping definitions 82 */ 83 Case[] cases(); 84 }