enums

[Rajiv Chelsea]

   
public class CoffeeTest1{
     public static void main(Sring[] args) {
         enum CoffeeSize {BIG, HUGE, OVERWHELMING} // error


         Coffee drink = new Coffee();
         drink.size = CoffeeSize.BIG;
   }
}
 

Why enum declaration is not allowed inside methods?

[Bear Bibeault]

Think of them as a type of class. Can you declare a class in a method?

[vikas mhatre]

Can you declare a class in a method?

As a method local inner class

[David Newton]

Bear Bibeault wrote:Think of them as a type of class. Can you declare a class in a method?

Yep.

package pathological;

public class ClassInMethod {

    public void methodWithClass() {
        System.out.println("Wat?");

        class ImaImaImaClass {
            public String drat() { return "Ohai."; }
        }

        System.out.println(new ImaImaImaClass().drat());
    }

    public static void main(String[] args) {
        new ClassInMethod().methodWithClass();
    }

}

[Rajiv Chelsea]

  enum CoffeeSize{BIG,HUGE,OVERWHELMING,3}  

Why does the above line of code give syntax error on token "3"?

[David Newton]

Because it's not a valid identifier.

[Rajiv Chelsea]

As read, enums are used for contants , so
can't we use primitive constants in it?

[Rob Spoor]

Because the enum names must follow the rules for Java identifiers. And you can't declare a variable called 3, now can you?

[Rajiv Chelsea]

An enum type is a type whose fields consist of a fixed set of constants. Common examples include compass directions (values of NORTH, SOUTH, EAST, and WEST) and the days of the week.
Because they are constants, the names of an enum type's fields are in uppercase letters.


The above is the definition of enum as given in Sun Doc,
basically its used for constants..

So why have been primitive constants disaalowed?

The "3" i gave in my enum declaration is not an identifier, its a constant which
is what enums are meant for..

[Sridhar Santhanakrishnan]

BIG,HUGE,OVERWHELMING are all identifiers for a constant. 3 however is a constant and cannot be used as an identifier.

Something similar to this...

 
int BIG =10;
int HUGE=15;

int 3; //error   

[Rajiv Chelsea]

   
package testenum;

enum CoffeeSize{BIG,HUGE,OVERWHELMING}

class Coffee{
	CoffeeSize size;
}

public class CoffeeTest1 {
	
	public static void main(String[] args){
		Coffee drink = new Coffee();
		drink.size = CoffeeSize.BIG;
		System.out.println(drink.size);
	}

}

 

    
package testenum;

class Coffee{
	enum CoffeeSize{ITALY,BRAZIL,FRANCE}
	CoffeeSize cs;
}

public class CoffeeTest2 {
	
	public static void main(String[] args){
		Coffee drink = new Coffee();
		drink.cs = Coffee.CoffeeSize.ITALY;
		System.out.println(drink.cs);
	}

}

I have the above two classes.
In the second code block, an error occurs saying class Coffee already exists in the package.
Why does not the same thing occur for enum CoffeeSize as i have declared it in both the
blocks of code and enum is also a type of class?

[Rob Spoor]

Because in the second example, the enum is not CoffeeSize - it's Coffee.CoffeeSize. It's a nested enum.

[Rajiv Chelsea]

Thanks for all the answers..

[Rajiv Chelsea]

the Java language designers made it optional to
put a semicolon at the end of the enum declaration (when no other declarations for
this enum follow):


Can I have some example codes of where semicolon is optional
and where semicolon is required?