how to convert class in scala into Algebraic Data Types?

Question

Currently I have two classes, how to transfer them to Algebraic Data Types? I think I can do something like this case class BlacklistDynamoDBUpdate(ruleName: String, whitelistedAccount, featureName: String) , but how to use those method in that class?

class DynamoDBUpdateBlacklist {
  private var features: Array[BlacklistDynamoDBUpdate] = _

  def getFeatures = features

  def setFeatures(features: Array[BlacklistDynamoDBUpdate]) = {
    this.features = features
  }
}

class BlacklistDynamoDBUpdate {
  private var ruleName: String = _
  private var whitelistedAccount: String = _
  private var featureName: String = _

  def getFeatureName: String = featureName

  def setFeatureName(featureName: String) = {
    this.featureName = featureName
  }

  def getRuleName: String = ruleName

  def setRuleName(ruleName: String) = {
    this.ruleName = ruleName
  }

  def getWhitelistedAccounts: String = whitelistedAccount

  def setWhitelistedAccounts(whitelistedAccount: String): Unit = {
    this.whitelistedAccount = whitelistedAccount
  }
}

I transfer a json into scala object, json look like this

"features": [ { "featureName": "***", "ruleName": "***", "whitelistedAccounts": "***" }], 

what I want is get those attributes value

Answer 1

If you need to parse json into idiomatic scala code then use simple case classes and library that is design to parse such jsons directly into those case classes (personally I sugest this one https://lihaoyi.com/upickle or this one https://circe.github.io/circe ).

here is example code that shows how to use upickle.

import upickle.default.{ReadWriter => RW, macroRW}

final case class DynamoDBUpdateBlacklist(features:Seq[BlacklistDynamoDBUpdate])
final case class BlacklistDynamoDBUpdate(featureName:String, ruleName:String, whitelistedAccounts:String)

object DynamoDBUpdateBlacklist {
  implicit val rw: RW[DynamoDBUpdateBlacklist] = macroRW
}
object BlacklistDynamoDBUpdate {
  implicit val rw: RW[BlacklistDynamoDBUpdate] = macroRW
}

//use it like that
import upickle.default._
println(
  read[DynamoDBUpdateBlacklist]("""
    {"features":[{ "featureName": "***", "ruleName": "***", "whitelistedAccounts": "***" }]}
  """)
)

//DynamoDBUpdateBlacklist(Vector(BlacklistDynamoDBUpdate(***,***,***)))

https://scalafiddle.io/sf/8eqFEfX/2