@Param support for enum

[Aleksey Shipilev]

On 06/30/2014 09:31 PM, Aleksey Shipilev wrote:
> On 06/25/2014 05:56 PM, Joe Kearney wrote:
>> The particular thing about enums was that when you add more constants or
>> rename you'll want those to be included in the parameter space, but
>> without the double book-keeping of adding the constant name in @Param as
>> well.
>>
>> For booleans obviously the set of values won't change. As you described
>> with enums, the set of possible boolean value is *small* and countable,
>> so it can be done. I'd argue that (@Param boolean) is so simple to add
>> and so obvious in what it means that it should be included.
> 
> There are basically three approaches:
> 
>  a) Everything should be explicit, and implicits are only there where
> the alternative is inconvenient. That is, all @Params require explicit
> default values, except for @Param(<enum>), which implicitly defaults to
> the entire enumset. This is what we have now.
>   + Consistent with only a single exception for out-of-band type
>   - Requires specifying values for low-cardinality types
> 
>  b) Everything should be explicit, and implicits are only there where
> the cardinality is low. That is, full enum set for @Param(<enum>), both
> false/true for @Param(<boolean>). This is what being suggested by Joe.
>   +- Consistency relies on definition of low-cardinality
> 
>  c) Everything may be implicit, and implicits include full domain for
> low-cardinality types, and the default values for every other type.
>   +- Consistency relies on definition of low-cardinality
>   +- Better consistency across the types?
> 
> There is no obvious choice between either three. Maybe there is
> something else I am overlooking; let's poll the audience!
>   https://surveymonkey.com/s/J3Y8ZSX

So, it does not look like current state is bad:
 http://cr.openjdk.java.net/~shade/jmh/implicit-params.png

This reinforces my belief we don't need to change the status quo with
regards to @Param(<boolean>). "Know what you are doing or don't do it"
is a good motto there :)

Thanks,
-Aleksey.