scala regular expressions example

gistfile1.scala

case class Line(id : Long, yesNo : Boolean, name : String, optional : Option[String], amount : Double)

object SimpleImport {
  // Create the field regex so you can compose them 
  //and be able to simply extract the information 
  val sourceFolder : String = "/home/sofoklis/Desktop"
  val digit = """~(\d*)~"""
  val double = """([-+]?[\d]*\.?[\d]+)*"""
  val text = """~([^~]*)~"""
  val separator = """\^"""

  // Create a simple function that will create an option from a string value
  def optionString(text : String) = text match {
    case null ⇒ None
    case t ⇒ t.trim match {
      case ""    ⇒ None
      case value ⇒ Some(value)
    }
  }

  // Convert whatever is a boolean in your files to a scala Option[boolean]
  def booleanFromString(value : String) : Option[Boolean] = value match {
    case null ⇒ None
    case ex ⇒ ex.trim match {
      case ""  ⇒ None
      case "Y" ⇒ Some(true)
      case "y" ⇒ Some(true)
      case "N" ⇒ Some(false)
      case "n" ⇒ Some(false)
      case _   ⇒ Some(false)
    }
  }

  def main(args : Array[String]) {
    ImportSample.loadData
    println("Finished")
  }
}

object ImportSample {
  import SimpleImport._
  val fileName = "sample"

  // This is where the magic happens, simply create a list of the fields you expect and 
  // create a regular expression for your full line
  val RegEx = List(digit, text, text, text, double).mkString(separator).r

  def loadData {
    // Get the file and read the lines
    val filePath = sourceFolder + "/" + fileName
    import scala.io.Source._
    val lines = fromFile(filePath).getLines

    //Loop the lines and match
    lines.foreach(line ⇒ line match {
      case RegEx(id, yesNo, name, optional, amount) ⇒ println(Line(id.toLong, 
        booleanFromString(yesNo).get,
        name, optionString(optional), amount.toDouble))
      case _ ⇒ println("Something Wrong!")
    })
  }
}