enums & switch statements

> let's try that again:

>

>

>

> How can I make the following situation work? > int i = 0;

>

> swtich(i) {

> case SomeEnum.ONE.ordinal():

> break;

> }

>

> Currently, this does not compile, but I think you get

> the idea

If you are going to use enums in then i has to be of enum type- it has to be of the same type. So with enums something like this:

enum Order {ONE, TWO, THREE}

Order i = Order.ONE;

switch(i) {

case ONE: //

case TWO:

case THREE:

}

snic.snaca at 2007-7-13 0:43:59 >

> > You have to switch on a constant value, not a

> > variable or the return of a method

>

> Exactly. So, in other words, there is no way to

> switch on an integer given only an enum, as I have

> illustrated?

No, In other words, you can't use the return value of a method in a "case" clause - it won't compile, as you're finding out

But you can switch on enums themselves. Mixing enums and numerical value is a poor idea, use the type safety or don't - but don't mix both

georgemca at 2007-7-13 0:43:59 >

> > > You have to switch on a constant value, not a

> > > variable or the return of a method

> >

> > Exactly. So, in other words, there is no way to

> > switch on an integer given only an enum, as I have

> > illustrated?

>

> You could go something like this

> > switch(SomeEnum.ONE.ordinal()) {

>case 1:

> case 2:

>

> }

>

> assuming ordinal() returns an int

Which wouldn't be any use at all in this instance. It's an entirely different value he wants to switch on. Simply guessing at combinations of method calls and members that might compile isn't really very useful

georgemca at 2007-7-13 0:43:59 >

You could just do:

switch(SomeEnum.values()[i]) {

case ONE:

... etc.

But this is almost certainly poor design. If your code depends on the ordinal values of enums it's not using them properly. Use EnumSet for looping etc. with enums.

malcolmmca at 2007-7-13 0:43:59 >