Case classes inheriting from abstract class

I'm currently learning Scala and I have some problems designing my case classes. I need two case classes that have the same properties. So I thought I would be a good idea to inherit from an abstract base class that defines these properties. However this code does not compile

abstract class Resource(val uri : String) case class File(uri : String) extends Resource(uri) case class Folder(uri : String) extends Resource(uri) 

because uri in the case class constructors would overwrite the uri property of the base class.

What would be the correct way to design this?

I want to be able to do something like this

val arr = Array[Resource](File("test"), Folder("test2")) arr.foreach { r : Resource => r match { case f : File => println("It's a file") case f : Folder => println("It's a folder") } } 

The "equivalent" Java code should be something like

abstract class Resource { private String uri; public Resource(String uri) { this.uri = uri } public String getUri() { return uri; } } // same for Folder class File extends Resource { public File(String uri) { super(uri); } } 

2 Answers

The correct syntax should be:

abstract class Resource { val uri: String } case class File(uri : String) extends Resource case class Folder(uri : String) extends Resource Stream[Resource](File("test"), Folder("test2")) foreach { r : Resource => r match { case f : File => println("It's a file") case f : Folder => println("It's a folder") } } 

EDIT

Without case classes:

abstract class Resource(val uri : String) class File(uri : String) extends Resource(uri) { override def toString = "..." } object File { def apply(uri: String) = new File(uri) } class Folder(uri : String) extends Resource(uri) { override def toString = "..." } object Folder { def apply(uri: String) = new Folder(uri) } 

Make these two case class extends a common trait which define it interface and it should work.

BTW, you need an identifier before the type clause in case statement.

trait Resource { val uri: String } case class File(uri : String) extends Resource case class Folder(uri : String) extends Resource val arr = Array[Resource](File("test"), Folder("test2")) arr.foreach { r : Resource => r match { case s: File => println("It's a file") case s: Folder => println("It's a folder") }}