RFR 9: 8077350 Process API Updates Implementation Review

[Roger Riggs]

Hi Alan,

For something to log from an inoperative destroy call, are you thinking 
it should
throw an exception?  In that case the return value could be void and the 
exception
message could expose the OS specific reason.

None of the currently available exceptions seem appropriate;
A bare RuntimeException might do but perhaps a new exception class is 
needed.

Thanks, Roger



On 5/14/15 8:30 AM, Alan Bateman wrote:
>
>
> On 13/05/2015 16:10, Roger Riggs wrote:
>> Hi Alan,
>>
>> Yes, the destroy use looks a bit odd. In Process, destroyForcibly
>> returns this so that the application can fluently wait for the 
>> termination to complete.
>> Returning Optional<ProcessHandle> enables the case to fluently
>> perform an action on the process when it does exit.
>>
>>     ProcessHandle ph = ...;
>>     ph.destroy().ifPresent(p -> p.onExit( ...));
>>
>> Optional.isPresent() provides a boolean if that's needed.
> Optional is good and the usages with parent(), etc. are nice update to 
> the API. Chaining methods invocations is good too.
>
> It's just destroy that seems a bit much as it's too easy to mix up 
> "present" and "alive", e.g.: the process was present so we attempted 
> to destroy it, it may or may not be present now. In that context using 
> ifPresent in this example is confusing to read because it's really 
> "was present, on its way to not being present" (if you know what I 
> mean). That's the only one that might need to be looked at again to 
> see if there are better candidates. Related to this is that the 
> destroy methods don't have a way to communicate anything useful to log 
> when they fail. With Process no long implementing ProcessHandle then 
> there is an opportunity to look at that again.
>
> -Alan.
>