Simple method to consolidate boilerplate code for using scalasql and upickle libraries together

[samikrc]

Recently I was trying to consolidate some boilerplate code to a Helper class so that a Scala 3 enum type can be used easily with both scalasql package and ujson package. The context here is that I had a bunch of case classes representing various database tables, and they have multiple enum fields in them. I also needed to read/write the same class to and from JSON as well.

Here is a way in which I was able to do this. Hope this helps.

import java.sql.*
import upickle.default.*
import scalasql.*
import scala.reflect.Enum

class EnumTypeHelper[T <: Enum](enumValueOf: String => T)
{
    /**
     * Implicit conversion to read/write a T value to/from a database
     * @return
     */
    given typeMapper: TypeMapper[T] = new TypeMapper[T]
    {
        override def jdbcType = JDBCType.NVARCHAR

        override def get(r: ResultSet, idx: Int): T = enumValueOf(r.getString(idx))

        override def put(r: PreparedStatement, idx: Int, v: T): Unit = r.setString(idx, v.toString)
    }

    /**
     * Implicit method to read/write type T from/to a ujson.Value
     * @return
     */
    given ReadWriter[T] = upickle.default.readwriter[ujson.Value].bimap[T](
        v => ujson.Str(v.toString),
        json => enumValueOf(json.str)
    )

    // The following will prevent incorrect type comparisons
    given CanEqual[T, T] = CanEqual.derived  
}

enum MyEnum
{
    case A
    case B
}
object MyEnum extends EnumTypeHelper[MyEnum](MyEnum.valueOf(_))

Without this helper class, I have to replicate this same code for each of the enums.