JEP 102 Process Updates revised API draft

[Roger Riggs]

Hi Anthony,

On 2/10/2015 2:12 PM, Anthony Vanelverdinghe wrote:
> Hi Roger
>
> This looks great already. My feedback is about process destruction:
>
> Why isn't ProcessHandle::isDestroyForcible a static method?
The Process API is subclassable and in that case the subclass
should be able to control that behavior.  When the specification refers to
implementation dependent it refers to the classes that implement Process.
The built-in ProcessBuilder and Runtime.exec that uses ProcessBuilder
define their implementation behaviors.

>
> For ProcessHandle::destroy and Process::destroy, I'd like to propose 
> replacing
> "Whether the process represented by this Process object is forcibly 
> terminated or not is implementation dependent."
> with:
> "The process represented by this Process object is forcibly terminated 
> if and only if isDestroyForcible returns true."
There is some API history to contend with and multiple implementations 
are possible.
An application library can provide a factory of Process instances with 
other kinds of behavior.

>
> Process::destroyForcibly contains the following phrase: "The default 
> implementation of this method invokes destroy() and so may not 
> forcibly terminate the process."
> Why doesn't the default implementation throw 
> UnsupportedOperationException if forcible termination is not supported 
> on/implemented for the current platform? If I write code like: 
> process.destroyForcibly().waitFor(), I'd assume it would finish in a 
> timely manner, but due to the default implementation, this may 
> actually not finish at all.
The evolution of the Process API has been long and uneven.  Destroy came 
first but was not predictable;
the destroyForcibly was added but destroy remained backward compatible 
(and still must be backward compatible).

Roger

>
> Kind regards, Anthony
>
>
> On 10/02/2015 0:25, Roger Riggs wrote:
>> Hi,
>>
>> After a protracted absence from working on JEP 102, the updated API 
>> draft
>> provides access to process hierarchies and individual process 
>> information;
>> as permitted by the OS. The relationship between Process and 
>> ProcessHandle
>> is clarified and the security model validated.
>>
>> Both Processes and ProcessHandles can be monitored using 
>> CompletableFuture
>> for termination and to trigger additional actions on Process exit.
>> Information about processes includes the total cputime, starttime, user,
>> executable, and arguments.
>>
>> Please review and comment:
>>    http://cr.openjdk.java.net/~rriggs/ph-apidraft/
>>
>> Thanks, Roger
>>
>>
>>
>>
>>
>