TypeDiscriminator · mybatis源码解析

~~~ /** * Copyright 2009-2019 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 org.apache.ibatis.annotations; import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; import org.apache.ibatis.type.JdbcType; import org.apache.ibatis.type.TypeHandler; import org.apache.ibatis.type.UnknownTypeHandler; /** * The annotation that be grouping conditional mapping definitions. * * <p><br> * <b>How to use:</b> * <pre> * public interface UserMapper { * @Select("SELECT id, name, type FROM users ORDER BY id") * @TypeDiscriminator( * column = "type", * javaType = String.class, * cases = { * @Case(value = "1", type = PremiumUser.class), * @Case(value = "2", type = GeneralUser.class), * @Case(value = "3", type = TemporaryUser.class) * } * ) * List<User> selectAll(); * } * </pre> * @author Clinton Begin */ @Documented @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface TypeDiscriminator { /** * Returns the column name(column label) that hold conditional value. * * @return the column name(column label) */ String column(); /** * Return the java type for conditional value. * * @return the java type */ Class<?> javaType() default void.class; /** * Return the jdbc type for column that hold conditional value. * * @return the jdbc type */ JdbcType jdbcType() default JdbcType.UNDEFINED; /** * Returns the {@link TypeHandler} type for retrieving a column value from result set. * * @return the {@link TypeHandler} type */ Class<? extends TypeHandler> typeHandler() default UnknownTypeHandler.class; /** * Returns conditional mapping definitions. * * @return conditional mapping definitions */ Case[] cases(); } ~~~