Scala CASE classes July 26, 2012

When you create a case class in scala say like

case class Something (id: Int)

you get the following from the compiler:

• the apply method so you can write Something(4) instead of new Something(4) when you are creating your objects
• the compiler adds the val since all the fields are immutable
• you get a copy function to create modified copies of your object like so:   Something(6).copy(something = 7) and by using named parameters you can change only the value that changes.

Benefits of case classes:

• immutability, you can count on them not changing after they are created
• very nice to use in pattern matching
• very nice to use with tree structures and sealed classes
• meaningfull equals, hashCode and toString methods, especiall they first 2 might not be trivial to write.