Scala案例类初始化

Question

Below is my case classes. How to initialise case class child in scala?

// case class 
case class parent(id: String, name: String, rNo: Int,
                  child: Option[Child])

case class Child(cid: String, Ctype: String,
                 group_category_id: String,
                 unlock_at: String, due_at: String)

val a: Child = if (x.child != None) { x.child.get } else { null }

If I declare as null, it will throw NullPointerException in case of else condition. How to solve that?

Answer 1

I don't think you should unwrap the Option[Child] so that it would be null if it was empty. You shouldn't use nulls when you write idiomatic Scala. I would keep it in an Option and use the map and flatMap methods on it, to access the child if it exists.

However, if you really want to, you can do it like this:

val a: Child = x.child.getOrElse(null)