...switch case...

[patnim17]

I am trying to use the java Switch Case statement like this.
String Status;
switch (Status){
case "A":
break;
case "B":
break;
case "C":
}

but it does not take a String type in the case construct. java complains that it requires an int...

is there a workaround?

 

[Diancecht]

If you're using just the first character, use

String yourString;

switch (yourString.charAt(0)) {

}

Other workarounds are a bunch of ifs or, if you're using Java 1.5, define an enumeration:

java.sun.com/docs/books/tutorial/ java/nutsandbolts/switch.html

Cheers,
Dian

 

[sedj]

Use an if/else if/else block.

There is absolutely no point at all in attemping to use a switch statement on an object (as opposed to a primitive) because a switch statement is optimized for primtives where the stack size is known. With an Object, the size is not know till runtime - hence objects are stored on the heap, rather than on the stack like primitives. This means that from an optimized point of view, if a switch statement were to be able to cope with Objects, its optimized runtime would be ruined.

So ... use the if/else if/else construct.

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http://www.primrose.org.uk

 

[Diancecht]

I don't agree, the switch/case statement is more structured than a bunch of ifs. Including the switch/case with object would only involve modifying the compiler to transalte into a bunch of ifs at bytecodes.

Cheers,
Dian

 

[sedj]

Yes, but it isn't a bunch of if/else if/else statements - thats the point ...

--------------------------------------------------
Free Java/J2EE Database Connection Pooling Software

http://www.primrose.org.uk

 

[timw]

It would be nice if the compiler could use the optimised stack approach for int-like selectors, whilst generating a non-stack version for selecting on objects. We'd get the best of both worlds then. I hate using if else if else if else ..........

Tim
---------------------------
"Your morbid fear of losing,
destroys the lives you're using." - Ozzy

 

[Diancecht]

I don't think it could be useful for general objects, as it's really diffcult to know an Object value at compile time.

I just claim it for Strings. It's really common to know at compile time which possible values an String will have.

That's not applicable, I think, to a general object. I'd never guess which value will have a HashMap or a URLEncoder instance.

Cheers,
Dian

 

[timw]

I was kinda wondering if it would (theoretically) make use of the (possibly) overridden 'equals()' method.

Tim
---------------------------
"Your morbid fear of losing,
destroys the lives you're using." - Ozzy