GenerateBeanCaseClass.scala

import java.beans.Introspector
import java.nio.file.{Files, Paths}


object GenerateBeanCaseClass extends App {
  val typeRenderings = Map[Class[_], String](
    classOf[String] -> "String",
    classOf[Boolean] -> "Boolean",
    classOf[Int] -> "Int"
  )

  val typeDefaults = Map[Class[_], String](
    classOf[String] -> "\"\"",
    classOf[Boolean] -> "false",
    classOf[Int] -> "0"
  )

  def renderType(c: Class[_]) = typeRenderings.getOrElse(c, c.getName)

  def renderDefault(c: Class[_]) = typeDefaults.get(c).fold("")(" = " + _)

  for (beanName <- args) {
    val clazz = Class.forName(beanName)
    val beanInfo = Introspector.getBeanInfo(clazz, classOf[Object])
    if(beanName == "com.zoho.books.model.TimeEntry")
      beanInfo.getPropertyDescriptors.find(_.getName == "startTimer")
        .foreach(_.setReadMethod(classOf[com.zoho.books.model.TimeEntry].getMethod("startTimer")))
    val caseClassName = clazz.getSimpleName
    val javaName = clazz.getName
    val props = beanInfo.getPropertyDescriptors.filter(p => p.getReadMethod != null && p.getWriteMethod != null)

    val sb = new StringBuilder
    sb ++= s"case class $caseClassName(\n"
    for (p <- props)
      sb ++= "  " + p.getName + ": " + renderType(p.getPropertyType) + renderDefault(p.getPropertyType) + ",\n"
    sb ++=
      s""") {
         |  def toJava = {
         |    val obj = new $javaName
         |${
        props
          .map(p => "    obj." + p.getWriteMethod.getName + "(" + p.getName + ")")
          .mkString("\n")
      }
         |    obj
         |  }
         |}
         |object $caseClassName {
         |  def fromJava(obj: $javaName): $caseClassName =
         |    $caseClassName(
         |${
        props
          .map(p => s"      ${p.getName} = obj." + p.getReadMethod.getName + ",")
          .mkString("\n")
      }
         |    )
         |}
         |""".stripMargin

    val path = Paths.get(s"src/main/scala/$caseClassName.scala")
    Files.createDirectories(path.getParent)
    Files.writeString(path, sb)
  }
}