Scala offers multiple constructs for representing a fixed set of values, among which case objects and enumerations stand out. While both serve similar purposes, they have distinct characteristics and use cases. In this article, we’ll explore the differences between case objects and enumerations in Scala, along with their respective advantages and use cases.

What are Case Objects?

Case objects in Scala are instances of case class which is a regular class with an added pattern-matching feature. A case object is like an object, but just like a case class has more features than a regular class, a case object has more features than a regular object.

Its features include:

1. It’s serializable.
2. It has a default hashCode implementation.
3. It has an improved toString implementation.

Because of these features, case objects are primarily used in two places (instead of regular objects):

1. When creating enumerations.
2. When creating containers for “messages” that you want to pass between other objects (such as with the Akka actors library).

Syntax:

caseObjName = caseClassName(parameter_values)

Example:

Program to illustrate the creation of case objects in Scala:

// Creating a Case Class
case class student(name: String, standard: Int, marks: Int, result: String )
object myObject {
    def main(args: Array[String]) {
        // Creating a case Object 
        val student1 = student("Prem", 10, 89, "A+")
        println("Case Object: " + student1)
    }
}

Output:

What is Enumeration?

Enumeration is a feature of Scala that is used to define a group of named constants accessed using the enum name and ids. The enums in Scala work similar to enum in other programming languages like C/C++, Java. The difference is in creation syntax. In Scala, the enum’s are created by extending an abstract class Enumeration.

abstract class Enumeration extends Serializable

This is different from classical enum creation syntax where we would use the keyword enum for creating Enumeration.

Syntax:

object enum_object extends Enumeration {

type enum_object = value

/// Assigning value

val name1 = Value(“value”)

}

Example:

Program to illustrate creation of Enumeration in Scala:

object Main extends Enumeration { 
    type Main = Value 
    val day1 = Value("Sunday") 
    val day2 = Value("Monday") 
    val day3 = Value("Tuesday") 
    val day4 = Value("Wednesday") 
    def main(args: Array[String]) {
        println("Value of Enum : " + Main.values ) 
    } 
} 

Output:

In the above code, we have created an object name Main which is used to create enumeration which contains days of the week. Then we have printed its value in the main method using the println.

Case Objects vs Enumerations