Question

I m a Scala beginner and this piece of code makes me struggle.

Is there a way to do pattern matching to make sure everything i pass to Data is of the correct type? As you can see i have quite strange datatypes...

class Data (
val recipient: String, 
val templateText: String, 
val templateHtml: String, 
val blockMaps: Map[String,List[Map[String,String]]], 
templateMap: Map[String,String]
)

...

val dataParsed = JSON.parseFull(message)
dataParsed match {
 case dataParsed: Map[String, Any] => {
  def e(s: String) = dataParsed get s
  val templateText = e("template-text")
  val templateHtml = e("template-html")
  val recipient = e("email")
  val templateMap = e("data")
  val blockMaps = e("blkdata")

  val dependencies = new Data(recipient, templateText, templateHtml, blockMaps, templateMap)
  Core.inject ! dependencies
 }

...

Answer 1

I guess your problem is you want to be able to patten match the map that you get from parseFull(), but Map doesn t have an unapply.

So you could pattern match every single value, providing a default if it is not of the correct type:

val templateText: Option[String] = e("template-text") match {
  case s: String => Some(s)
  case _ => None
}

Or temporarily put all the data into some structure that can be pattern matched:

val data = (e("template-text"), e("template-html"), e("email"), e("data"),
            e("blkdata"))

val dependencies: Option[Data] = data match {
  case (templateText: String,
        templateHtml: String,
        blockMaps: Map[String,List[Map[String,String]]],
        templateMap: Map[String,String]) =>
    Some(new Data(recipient, templateText, templateHtml, blockMaps, templateMap))
  case _ => None
}

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