New JEP: Switch Expressions for the Java Language

forax at forax at
Wed Dec 13 10:08:04 UTC 2017

> De: "Brian Goetz" <brian.goetz at>
> À: "Kevin Bourrillion" <kevinb at>
> Cc: "Remi Forax" <forax at>, "amber-spec-experts"
> <amber-spec-experts at>
> Envoyé: Lundi 11 Décembre 2017 20:28:17
> Objet: Re: New JEP: Switch Expressions for the Java Language


>>    * Allowing `throw` as the RHS of a case makes sense, but let's carefully think
>>    through the ramifications of making it an expression in general. Do we really
>>    want to see code like this? void foo(Bar bar) { bar.isValid() || throw new
>>     IllegalArgumentException(); }

> OK, let's pull on that string. The next logical place for it is conditional
> expressions:

> String s = (x >= 0) ? Integer.toString(x) : throw new IAE();

> This seems pretty reasonable too, though the if-else version is not horribly
> broken either. What about conditionals in method invocation context:

> m(x > 0 ? Integer.toString(x) : throw new IAE())

> I know I've wanted to be able to do this at times, though again, I've worked
> around it and lived, and surely it could be abused.

> I'm OK cutting this one back.

I think we should only allow throw as an expression if the precedent symbol was '->', i.e. only allows throw as an expression in lambda body and in the body of an expression switch. 
It seems to cover what we want without making the code too un-java-y. 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the amber-spec-experts mailing list