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How to use Enum in Switch?

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Enums introduced in Java 5.0 (Read: New features in Java 5.0) allows switching to be done based on the enums values. It is one of the greatest new features introduced from the version 5.0. Prior to Java 1.4, switch only worked with int, short, char, and byte values. However, since enums have a finite set of values, Java 1.5 adds switch support for the enum. Some of the advantages of using enums are it is strongly typed, Comparing enums is faster, you can use == instead equals() and Enums can implement interfaces, methods and functions.

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Here’s an example of using an enum in a switch statement.

[code lang=”java”]
public class EnumSwitcher {
public enum Grade { A, B, C, D, F, INCOMPLETE };

public static void main(String[] args) {
Grade examGrade = Grade.C;

System.out.println(‘Switching based on the enums values.’);
System.out.println();
switch (examGrade) {
case A:
System.out.println(‘The students grade is ‘ + Grade.A);
break;
case B: // fall through to C
case C:
System.out.println(‘The students grade is ‘ + Grade.C);
break;
case D: // fall through to F
case F:
System.out.println(‘The students grade is ‘ + Grade.F);
break;
case INCOMPLETE:
System.out.println(‘The students grade is ‘ + Grade.INCOMPLETE);
break;
default:
System.out.println(‘The students grade is unknown.’);
break;
}

}
}[/code]
Given below is the output of the above program.
[code lang=”java”]
Switching based on the enums values.

The students grade is C[/code]

As you can see from the above example, there is nothing special in using an enum with a switch case statement.

Adding methods to an Enum

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Enums introduced in Java 5.0 are just compiled java classes with some extra behavior. So you can basically do whatever you can in a normal java class inside an enum as well. That includes adding methods , class level variables and constructors to an enum.

Adding methods to an enum works just like adding methods to a normal Java class. Here’s an example of using an adding methods to an enum:

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[code lang=”java”]
public class EnumMethods {
public enum Laptops {
SONY(1), HP(2), DELL(3), TOSHIBA(4), ACER(5), IBM(6);
private int rating;
Laptops(int rating){
this.rating = rating;
}
public int getRating(){
return rating;
}
};
public static void main(String[] args) {
Laptops rated = Laptops.DELL;
System.out.println("Using enum method to get the rating of laptop.");
System.out.println();
switch (rated) {
case SONY:
System.out.println("The laptop rating is " + Laptops.SONY.getRating());
break;
case HP:
System.out.println("The laptop rating is " + Laptops.HP.getRating());
break;
case DELL:
System.out.println("The laptop rating is " + Laptops.DELL.getRating());
break;
case TOSHIBA:
System.out.println("The laptop rating is " + Laptops.TOSHIBA.getRating());
break;
case ACER:
System.out.println("The laptop rating is " + Laptops.ACER.getRating());
break;
case IBM:
System.out.println("The laptop rating is " + Laptops.IBM.getRating());
break;
default:
System.out.println("The laptop has got no rating.");
break;
}
}
}
[/code]

Given below is the output of the above program.

[code lang=”java”]
Using enum method to get the rating of laptop.

The laptop rating is 3
[/code]

As you can see from the above example, you can add methods to an enum to add more value to the developers using your enum.