Enum

How to use Enum?

Enums can be used like a class.

public enum Temperature
{
HIGH,
MEDIUM,
LOW
}

- The above written enum will be saved as Temperature.java and would be compiled in the same way class is compiled.
- When compiler find the word enum it understands that this is not a class but an enum.

when later we need to access it we can access it like this:

Temperature t=Temperature.HIGH;

Let us write a small code to access the enum now

AccessEnum.java

class AccessEnum 
{
 public static void main(String[] args) 
 {
  Temperature t=Temperature.HIGH;
  if(t==Temperature.HIGH)
  {
   System.out.println("Temperature is High");
  }
 }
}

Enums can also hold fields as well as methods. 

public enum Temperature
{
 HIGH(1),// -----------> will call the constructor and pass value 1
 MEDIUM(2),//-------> will call the constructor and pass value 2


 LOW(3);//------------> will call the constructor and pass value 3
//A semi colon should be used to mark the end of constants.

 public final int i;

 Temperature(int i)
 {
  this.i=i;
 }
}

Enums can also contain methods.

public enum Temperature
{
 HIGH(1),// -----------> will call the constructor and pass value 1
 MEDIUM(2),//-------> will call the constructor and pass value 2
 LOW(3);//------------> will call the constructor and pass value 3
//A semi colon should be used to mark the end of constants.

 public final int i;

 Temperature(int i)
 {
  this.i=i;
 }
       
       public int getI()

      {
        return i;
      }


}

Now let us again modify our AccessEnum.java

class AccessEnum 
{
 public static void main(String[] args) 
 {
  Temperature t=Temperature.HIGH;
  if(t==Temperature.HIGH)
  {
   System.out.println("Temperature is High");
   System.out.println(t.getI());
  }
 }
}

Iterating through Enum

Every enum have got a static method values() which return the array of constants in enum.

for(Temperature t:Temperature.values())
{
System.out.println(t);
}

Facts about Enum