package com.xxx.typehandler;

import com.xxx.utils.JsonUtil;
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;

import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * mapper里json型字段到类的映射。
 * 用法:
 * 入库：#{item.myObject, typeHandler=com.xxx.typehandler.JsonTypeHandler}
 * 出库：
 * <resultMap>
 *      <result property="jsonDataField" column="json_data_field" javaType="com.xxx.MyClass" typeHandler="com.xxx.typehandler.JsonTypeHandler"/>
 * </resultMap>
 *
 * @author xxx
 * @date 2016/5/31 19:33
 */
public class JsonTypeHandler<T extends Object> extends BaseTypeHandler<T> {

    private Class<T> clazz;

    public JsonTypeHandler(Class<T> clazz) {
        if (clazz == null) throw new IllegalArgumentException("Type argument cannot be null");
        this.clazz = clazz;
    }

    @Override
    public void setNonNullParameter(PreparedStatement ps, int i, T parameter, JdbcType jdbcType) throws SQLException {
        ps.setString(i, JsonUtil.toString(parameter));
    }

    @Override
    public T getNullableResult(ResultSet rs, String columnName) throws SQLException {
        return JsonUtil.toObject(rs.getString(columnName), clazz);
    }

    @Override
    public T getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
        return JsonUtil.toObject(rs.getString(columnIndex), clazz);
    }

    @Override
    public T getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
        return JsonUtil.toObject(cs.getString(columnIndex), clazz);
    }
}