ENUM IN JAVA

Enum is a type of class which is final. It is created by using the keyword “enum”. It is used for defining set of named constants those representing a menu kind of items. For example – Hotel menu, Bar menu etc. Before java 5 these items were created using class. Class has a problem in accessing these menu items, that it cannot return or print item name as it is declared, instead it returns or prints its value.

Example with class –

class Months{

          static final int jan=1;

          static final int feb=2;

}

public class Year {

          public static void main(String[] args)

          {

                   System.out.println(Months.jan);

                   System.out.println(Months.feb);

          }

}

Output –

1

2

Example with enum –

public enum Months {

          jan,feb;

}

class Year{

          public static void main(String[] args)

          {

                   System.out.println(Months.jan);

                   System.out.println(Months.feb);

          }

}

Output –

jan

feb

Example –

public class Test2 {

          public enum Season { WINTER, SPRING, SUMMER, FALL }

          public static void main(String[] args) {

                   for (Season s : Season.values()) 

                             System.out.println(s); 

          }

}

Output –

WINTER

SPRING

SUMMER

FALL

Note - The java compiler internally adds the values() method when it creates an enum. The values() method returns an array containing all the values of the enum.

Example –

public class Test2 {

          public enum Season { WINTER, SPRING, SUMMER, FALL }

          public static void main(String[] args) {

                   Season s = Season.WINTER;

                   System.out.println(s);

          }

}

Output –

WINTER

Example –

public class Test2 {

          enum Season{  

                   WINTER(5), SPRING(10), SUMMER(15), FALL(20);                     

                   private int value; 

                   private Season(int value){ 

                   this.value=value;

                   }

          }

          public static void main(String[] args) {

                   for (Season s : Season.values()) 

                             System.out.println(s+" "+s.value);

          }

}

Output –

WINTER 5

SPRING 10

SUMMER 15

FALL 20