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Can't a switch use final parameters?

Jeff Bosch
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Joined: Jul 30, 2003
Posts: 805
I tried building a method with a configurable switch statement, to test how method-local parameters and variables work when declared final. A switch statement needs constant expressions for the case statement, and the final local variables/parameters are constant. Do I get a compiler error because the case labels are potentially not constant at compile time?
Here are relevant snippets of the code:

I even tried assigning a value to a local final variable through the parameters:

But I had the same error in both cases:

Is this because these final varables must be declared and initialized before compilation? I thought the answer was 'no' because you can initialize final variables through constructors with no problem. But my results tell me that I don't really understand when a final variable is a constant and when it's not. Note that assigning a local value to one of the final variables removes the compiler error: final int x = 2;
Any help?
Thanks!
Regards,
Jeff


Give a man a fish, he'll eat for one day. Teach a man to fish, he'll drink all your beer.
Cheers, Jeff (SCJP 1.4, SCJD in progress, if you can call that progress...)
Barry Gaunt
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Joined: Aug 03, 2002
Posts: 7729
Jeff, the thing after the case must be a ConstantExpression as in The Java Language Specification paragraph 15.8
So anything which is a formal parameter to a method is a "no-no".


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Jeff Bosch
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Joined: Jul 30, 2003
Posts: 805
Thanks, Barry.
I found the answer this morning and was hoping I could post a "nevermind" message before anyone took the time to respond!
Regards,
Jeff
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Can't a switch use final parameters?