001/*
002 *  Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
003 *  <p>
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 *  <p>
008 *  http://www.apache.org/licenses/LICENSE-2.0
009 *  <p>
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 */
016package com.mybatisflex.core.keygen;
017
018import com.mybatisflex.annotation.KeyType;
019import com.mybatisflex.core.FlexConsts;
020import com.mybatisflex.core.exception.FlexExceptions;
021import com.mybatisflex.core.row.Row;
022import com.mybatisflex.core.row.RowKey;
023import com.mybatisflex.core.util.StringUtil;
024import org.apache.ibatis.executor.Executor;
025import org.apache.ibatis.executor.keygen.KeyGenerator;
026import org.apache.ibatis.mapping.MappedStatement;
027
028import java.sql.Statement;
029import java.util.Map;
030
031/**
032 * 通过 java 编码的方式生成主键
033 * 当主键类型配置为 KeyType#Generator 时，使用此生成器生成
034 * {@link KeyType#Generator}
035 */
036public class RowCustomKeyGenerator implements KeyGenerator {
037
038    protected RowKey rowKey;
039    protected IKeyGenerator keyGenerator;
040
041
042    public RowCustomKeyGenerator(RowKey rowKey) {
043        this.rowKey = rowKey;
044        this.keyGenerator = KeyGeneratorFactory.getKeyGenerator(rowKey.getValue());
045
046        ensuresKeyGeneratorNotNull();
047    }
048
049    private void ensuresKeyGeneratorNotNull() {
050        if (keyGenerator == null) {
051            throw FlexExceptions.wrap("The name of \"%s\" key generator not exist.", rowKey.getValue());
052        }
053    }
054
055
056    @Override
057    public void processBefore(Executor executor, MappedStatement ms, Statement stmt, Object parameter) {
058        Row row = (Row) ((Map) parameter).get(FlexConsts.ROW);
059        try {
060            Object existId = row.get(rowKey.getKeyColumn());
061            // 若用户主动设置了主键，则使用用户自己设置的主键，不再生成主键
062            // 只有主键为 null 或者 空字符串时，对主键进行设置
063            if (existId == null || (existId instanceof String && StringUtil.isBlank((String) existId))) {
064                Object generateId = keyGenerator.generate(row, rowKey.getKeyColumn());
065                row.put(rowKey.getKeyColumn(), generateId);
066            }
067        } catch (Exception e) {
068            throw FlexExceptions.wrap(e);
069        }
070    }
071
072
073    @Override
074    public void processAfter(Executor executor, MappedStatement ms, Statement stmt, Object parameter) {
075        //do nothing
076    }
077
078}