What are Scala standard exceptions?

Question

What are the common standard exceptions in Scala? I am especially interested in how is .Net's NotImplementedException equivalent called?

UPDATE: The answer about the NotImplementedException seems to be org.apache.commons.lang.NotImplementedException

Uplift

Answer 1

Almost nothing:

package scala {
  final class MatchError(obj: Any) extends RuntimeException
  final class UninitializedError extends RuntimeException("uninitialized value")
  final case class UninitializedFieldError (msg: String) extends RuntimeException(msg)

  package util.regex {
    class SyntaxError(e: String) extends RuntimeException(e)
  }

  package xml {

    class BrokenException() extends java.lang.Exception
    case class MalformedAttributeException(msg: String) extends RuntimeException(msg)

    package dtd {
      case class ValidationException(e: String) extends Exception(e)
    }

    package include {
      class CircularIncludeException(message: String) extends XIncludeException
      class UnavailableResourceException(message: String) extends XIncludeException(message)
      class XIncludeException(message: String) extends Exception(message)
    }

    package parsing {
      case class FatalError(msg: String) extends java.lang.RuntimeException(msg)
    }
  }
}

The rest comes from Java, which cover pretty much all corners. It begs the question of what these Scala methods throw on other platforms, doesn't it?

Radiancy

That gives a pretty fair idea of just how easy it is to throw your own custom Exceptions and even errors if it works with Java. Just make a one line class in an object and use as needed. final class MyException(arg:String) extends RuntimeException() or as seen in FatalError with java.lang.RuntimeException(msg). Nice one Sobral. – Flexion

Answer 2

The NotImplementedException is currently being considered for Scala 2.10, probably. See this thread.

Wilfordwilfred

UnsupportedOperationException of course isn't being considered for Scala 2.10. It has been part of the Java library for a long time. The thread is about adding a conveniece method that throws it to Predef. – Hickox

First of all, UnsupportedOperationException and NotImplementedException mean totally different things and both are needed (I used to use both of them actively in C# projects of mine). And the question is what to use today, in Scala 2.9.1? I use to define a class and then implement it method-by-method, using "throw new NotImplementedException()" as not yet implemented methods bodies and compiling the project many times before I implement everything. But in Scala it seems like I have to implement all the functions by returning some dummy data - this may cause bugs and is just annoying. – Uplift

As of 2.10, ??? has been added to Predef. You can now write code like class Thing { def getThing = ??? }. Calling getThing will raise scala.NotImplementedError with the message "an implementation is missing". – Folliculin

Answer 3

You can just use whatever default already exists in Java. Scala doesn't really add anything to the standard exceptions in Java.

Hickox