Creating Case Class from parameters of an Array

Question

I have an Array of String: EmpArray = Array(emp_id,emp_name,city)

Instead of manually creating case class (say -- case Class Emp (val emp_id: String, val emp_name:String, val city:String)

can I create a case class from the Array itself

case class Emp (EmpArray(0), EmpArray(1), EmpArray(2)) -- //hypothetical

can anything of such sort possible in scala?

You might want to [take a look at this](https://stackoverflow.com/questions/39137175/dynamically-compiling-scala-class-files-at-runtime-in-scala-2-11). — Andrey Tyukin, Dec 21 '18 at 20:15

score 1 · Accepted Answer · answered Dec 21 '18 at 22:12

If you really have to, you can do it with runtime compilation:

import scala.reflect.runtime.universe
import scala.tools.reflect.ToolBox

def compileCaseClass(name: String, values: (String, String)*): Class[_] = {
  val tb = universe.runtimeMirror(getClass.getClassLoader).mkToolBox()
  val code = s"""
    |case class $name(${values.map{case (n, t) => n + ": " + t}.mkString(",")})
    |scala.reflect.classTag[$name].runtimeClass
  """.stripMargin
  println(code)
  tb.compile(tb.parse(code))().asInstanceOf[Class[_]]
}

Usage example:

val arr = Array("emp_id", "emp_name", "city")
val types = Array.fill(3){"String"}
val emp = compileCaseClass("Emp", (arr zip types): _*)
val inst = emp.getConstructors.head.newInstance("foo", "bar", "baz")
println(inst)

it indeed outputs the usual toString of a case-class instance:

Emp(foo,bar,baz)

Note that it requires the reflection / compiler toolbox as dependency: it's there if you are running it in the REPL or as a script, but in ordinary projects, you have to add it as separate dependency.

Creating Case Class from parameters of an Array

1 Answers1