RFR: 8288327: Executable.hasRealParameterData should not be volatile [v2]

[Сергей Цыпанов]

On Fri, 17 Jun 2022 06:27:12 GMT, liach <duke at openjdk.org> wrote:

>> Another approach would be to keep the parameter array and the boolean in a record, and mark the record field as stable, possibly like what's done in #6889. Keeping them in a record like:
>> 
>> record ParameterData(Parameter[] parameters, boolean real) {}
>> 
>> private transient @Stable ParameterData parameterData;
>> 
>> private ParameterData parameterData() {
>>     ParameterData data = parameterData;
>>     if (data != null)
>>         return data;
>>     // Create parameter data, cache and return
>> }
>> 
>> boolean hasRealParameterData() { return parameterData().real(); }
>> private Parameter[] privateGetParameters() { return parameterData().parameters(); }
>> 
>> 
>> This code should be more maintainable in the long run as well, with more straightforward concurrency and caching model.
>
> If my record approach is used, `hasRealParameterData()` and `privateGetParameters()` should be manually inlined instead, for code clarity. Alternatively, you can rename the components to like `sharedArray`/`sharedParameters`, `isReal` to make the call sites like `parameterData().sharedParameters().clone()` or `parameterData().isReal()` more descriptive.
> 
> Currently, `hasRealParameterData` is only used in `Executable::getAllGenericParameterTypes`, and `privateGetParameters` only in `Executable::getParameters` (except the unintuitive usage to initialize the parameter data), so the impact of such a refactor and inline would be small.

@liach Good point, done!

-------------

PR: https://git.openjdk.org/jdk/pull/9143