Enums

[leroy tsruya]

Hi All!

I have some enums in my code:

public enum Days {
  SUNDAY, MONDAY, TUESDAY, WEDNSDAY, THURSDAY, FRIDAY, SATURDAY;
}

public enum Months{
  JAN, FEB, MAr, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC;
}

I want to be able to retrieve the enum, JUN for example, by it's ordinal, 5.
So, i created a static method, inside Month:

public static Months getMonth(int ord){
   for(Months m : Months.values()){
      if(ord == m.ordinal()){
         return m;
       }
    }
    return null;
}

now, I also want to make the same method in Days.
Is there a way to make a capsulate class so I won't have to code the same method in all my enums?

[Tom Reilly]

Months.values() returns an array. You can use the ordinal as the index into the array to get your enum. So you don't have to loop to find it. Of course, you'll have to make sure your ordinal is correct - check to make sure the ordinal you have is within the bounds of the array or you'll get an exception. Does this satisfy your query or do you need more information?

[Wouter Oet]

I'm sorry but Enums implicitly extend java.lang.Enum and because of that it can't extends anything else.

You could also code it like this:

public static Months getMonth(int ord){   
   if(ord >= 0 && ord<values().length)   
      return values()[ord];
    return null;   
}      

And you could create a util function ala:

public static <T extends Enum<T>> T get(Class<T> enumType, int ord) {
	if(ord >= 0 && ord<enumType.getEnumConstants().length)   
		return enumType.getEnumConstants()[ord];
	return null;   
}    

But I find that last one ugly because it uses reflection.

[leroy tsruya]

wow Wouter Oet, that is exactly what I was looking for! Thanks