Case Class in Scala

Case classes are primarily intended to create “immutable records” that you can easily use in pattern-matching expressions. Perhaps as a result of this, case class constructor parameters are val by default.

Defining a class as a case class results in a lot of boilerplate code being generated, with the following benefits:

• An apply method is generated, so you don’t need to use the new keyword to create a new instance of the class.

     scala> case class Person(name: String, reltion: String)

     scala> val emily = Person("Emily", "niece")

• Accessor methods are generated for the constructor parameters because case class constructor parameters are val by default. Mutator methods are also generated for parameters declared as var.

• A good, default toString method is generated.
• An unapply method is generated, making it easy to use case classes in match expressions.

      scala> emily match {case Person(n, r) => println(n, r)}

• equals and hashCode methods are generated.
• A copy method is generated.