pattern matching on a series of values in scala
-
05-07-2019 - |
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
}
...
Solution
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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