Generate random records based on Schema in Scala without Spark

program.scala

import java.io.{BufferedWriter, DataOutputStream, File, FileWriter}

import scala.io.Source.fromFile
import scala.util.Random
import scala.util.parsing.json.JSON

object DBGenSansSpark {
  val master = "local[2]"
  val appName = "testing"

  val r = scala.util.Random
  def generators = Map[String, Unit => Any](
    "INT" -> (_ => r.nextInt(100)),
    "STRING" -> (_ => Random.alphanumeric.take(8).mkString("")),
    "DOUBLE" -> (_ => r.nextDouble),
    "LONG" -> (_ => r.nextLong)
  )


  type JSONMap = Map[String, String]

  def argsParser(args: Array[String]) = {
    args.map {
      arg =>
        (arg.split("--")(1).split("=")(0), arg.split("--")(1).split("=")(1))
    }.toMap
  }

  def main(args: Array[String]): Unit = {
    val argsMap = argsParser(args)
    val schemaBasePath = argsMap("schemaBasePath") // /Users/$user/workspace/test_data/schemas
    val outputBasePath = argsMap("outputBasePath") // /Users/$user/workspace/test_data/output
    val numRecords = argsMap("numRecords").toInt
    val tableFiles = argsMap("tables").split(",").map { tableName => (tableName, s"${schemaBasePath}/${tableName}.json") }.toMap //table1,table2
    val jsonSchemasForTables: Map[String, JSONMap] = tableFiles.map { case (k, v) =>
      (k, JSON.parseFull(fromFile(v).getLines.mkString).get.asInstanceOf[JSONMap])
    }

    jsonSchemasForTables.map {

      case (tableName, json) =>

        val records = (1 to numRecords).toStream.map { _ => generateRowForSchemaType(json) }
        (tableName, records)

    }.foreach {
      case (tableName, records) =>
        val tableOutputPath = s"$outputBasePath/$tableName/part-0000.csv"
        println(s"Writing files for table: $tableName at location $tableOutputPath")
        val file = new File(tableOutputPath)
        file.getParentFile().mkdirs()
        file.createNewFile()
        val bw = new BufferedWriter(new FileWriter(file))
        records.foreach {
          record =>
            bw.write(record.mkString("\u0001"))
            bw.newLine()
        }
        bw.flush()
        bw.close()
        println(s"Write completed for files for table: $tableName at location $tableOutputPath")
    }

  }

  private def generateRowForSchemaType(json: JSONMap) = {
    json.mapValues(x => generators(x).apply()).values.toSeq
  }

}