How do I cast a variable in Scala?

scala

Solution

The preferred technique is to use pattern matching. This allows you to gracefully handle the case that the value in question is not of the given type:

g match {
  case g2: Graphics2D => g2
  case _ => throw new ClassCastException
}

This block replicates the semantics of the `asInstanceOf[Graphics2D]` method, but with greater flexibility. For example, you could provide different branches for various types, effectively performing multiple conditional casts at the same time. Finally, you don't really need to throw an exception in the catch-all area, you could also return `null` (or preferably, `None`), or you could enter some fallback branch which works without `Graphics2D`.

In short, this is really the way to go. It's a little more syntactically bulky than `asInstanceOf`, but the added flexibility is almost always worth it.

Problem

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