app.myoss.cloud.mybatis.table.annotation.SequenceKey Maven / Gradle / Ivy

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/*
 * Copyright 2018-2018 https://github.com/myoss
 *
 * 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 app.myoss.cloud.mybatis.table.annotation;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import org.apache.ibatis.executor.keygen.KeyGenerator;

import app.myoss.cloud.mybatis.executor.keygen.SequenceKeyGenerator;
import app.myoss.cloud.mybatis.table.Sequence;
import app.myoss.cloud.mybatis.table.TableMetaObject;
import app.myoss.cloud.mybatis.table.annotation.SequenceGenerator.Order;

/**
 * 用于 {@link GenerationType#SEQUENCE_KEY} 策略，使用 {@link Sequence} 接口实现类来生成，由
 * {@link SequenceKeyGenerator} 触发调用
 *
 * @author Jerry.Chen
 * @since 2018年4月30日 下午10:47:11
 * @see Sequence
 * @see SequenceKeyGenerator
 */
@Target({ FIELD })
@Retention(RUNTIME)
@Documented
public @interface SequenceKey {
    /**
     * 从 {@link KeyGenerator} 中获取到的返回值，要设置到哪几个的属性字段中
     * 
     * 可以设置多个字段
     * 
此字段仅用于 {@link KeyGenerator} 实现类中
     * 
如果 {@link SequenceGenerator} 注解不是放在 Field 上面，则需要设置。
     * 
如果 {@link SequenceGenerator} 注解放在 Field 上面则，取此字段的属性名。
     * 
     *
     * @return 主键属性字段名
     */
    String[] keyProperty() default {};

    /**
     * 从 {@link KeyGenerator} 中获取到的返回值，和 {@link #keyProperty} 的映射关系。绝大多数情况下，如果
     * {@link KeyGenerator} 返回的的值是单一的列，则不需要设置 {@code keyColumn }
     * 
     * 可以设置多个字段
     * 
可选属性
     * 
默认会从对应的 keyProperty 字段中获取"数据库字段名"
     * 
     *
     * @return 序列结果中取哪几个字段名
     */
    String[] keyColumn() default {};

    /**
     * {@link Sequence} 接口实现类
     *
     * @return 序列的实现类
     */
    Class sequenceClass();

    /**
     * (Optional) {@code sequenceClass} 对应的 Spring Bean instance name
     *
     * @see TableMetaObject#getSequenceBean(String)
     * @return 序列的 Spring Bean 实例名称
     */
    String sequenceBeanName() default "";

    /**
     * (Optional) The name of the database sequence object from which to obtain
     * primary key values.
     * 
     * Defaults to a provider-chosen value.
     *
     * @return 序列名称
     */
    String sequenceName() default "";

    /**
     * (Optional) {@link KeyGenerator} 在 INSERT 之前/之后执行
     *
     * @return 在 INSERT 之前/之后执行
     */
    Order order() default Order.BEFORE;
}