Elegant way to validate scala map - scala

Question

My program receives a scala map, the requirements is to validate this map (key-value pairs). Ex: validate a key value, change its value to an acceptable format etc. In a rare case, we update the key as well before passing the map to the down layer. Its not always required to update this map , but only when we detect that there are any unsupported keys or values. However, we have to check all key/value pairs. I'm doing some thing like this:
private def updateMap ( parameters: Map[String, String]): Map[String, String] = {
parameters.map{
case(k,v) => k match { case "checkPool" =>
(k, (if (k.contains("checkPool"))
v match {
case "1" => "true"
case _ => "false"
}
else v))
case "Newheader" => (k.replace("Newheader","header"),v)
case _ =>(k,v)
}
case _ => ("","")
}
}
Like this the code increases for doing the validation and converting the keys/values to supported ones. Is there a cleaner way of doing this validation in Scala for a map?
Thanks

Answer 1

It will be clearer if you put all your patterns above one another:
parameters.map{
case (k#"checkPool", "1") => k -> "true"
case (k#"checkPool", _") => k -> "false"
case ("Newheader", v) => "header" -> v
// put here all your other cases
case (k, v) => k -> v //last possible case, if nothing other matches
}
For clarity, you can also put different validators in partial functions:
type Validator = PartialFunction[(String, String), (String, String)
val checkPool: Validator = {
case (k#"checkPool", "1") => k -> "true"
case (k#"checkPool", _") => k -> "false"
}
val headers: Validator = {
case ("Newheader", v) => "header" -> v
}
And then put all your validators one after the other in your map:
parameters.map(
checkPool orElse
headers orElse
... orElse
PartialFunction(identity[(String, String)]) //this is the same as case (k, v) => k -> v
)

Answer 2

simple if else condition matching seems to be the best choice.
def updateMap(parameters: Map[String, String]): Map[String, String] = {
parameters.map(kv => {
var key = kv._1
var value = kv._2
if(key.contains("checkPool")){
value = if(value.equals("1")) "true" else "false"
}
else if(key.contains("Newheader")){
key = key.replace("Newheader", "header")
}
(key, value)
})
}
You can add more else if conditions