Review request for 6829503

[Mandy Chung]

Hi Martin,

Thanks for the quick review.

Users should only add their shutdown hooks via the 
System.addShutdownHook() method.   java.lang.Shutdown is an 
implementation class for registering internal hooks besides application 
shutdown hooks - including the shutdown hook for Console and 
DeleteOnExitHook.   Applications should not use the Shutdown#add method.
> How do you manage the order of independently developed shutdown hooks? 
I assume you're concerned with application shutdown hooks.   The order 
will be managed by ApplicationShutdownHooks (in the order when a hook is 
added).  Are you concerned with other use of Shutdown#add? 

Mandy

Martin Buchholz wrote:
> Thanks for your quick response on this.
>
> A quick review says: looks good to me.
> Someone should give it a more thorough review.
> -----
> The solution of allowing shutdown hooks of a particular type to be added
> during shutdown before that slot is reached is clever.
>
> I'm sure there are use cases for users to be able to do the same thing
> with their own shutdown hooks, but it would be tricky to provide such
> a facility in a clean way.  How do you manage the order of independently
> developed shutdown hooks?  Probably still a research problem.
>
> -----
>
> the last shutdown hook to invoke.
> =>
> the last shutdown hook to be invoked.
>
> Martin
>
> On Fri, Apr 17, 2009 at 15:05, Mandy Chung <Mandy.Chung at sun.com> wrote:
>   
>> 6829503: addShutdownHook fails if called after shutdown has commenced.
>>
>> Webrev at:
>>  http://cr.openjdk.java.net/~mchung/6829503/webrev.00/
>>
>> I change the Shutdown#add method to take the registerShutdownInProgress
>> parameter.  If set to true, the specified shutdown hook is allowed to be
>> registered while shutdown is in progress.  The method will throw
>> IllegalStateException if the shutdown process already passes this slot.
>> DeleteOnExitHook is the last shutdown hook to be invoked and it will not be
>> invoked until all application shutdown hooks finish (see
>> ApplicationShutdownHooks.runHooks()).  So any file added to the delete on
>> exit list by the application shutdown hooks will be handled by the
>> DeleteOnExitHook.
>>
>> The LoggingDeadlock2.java test passes with this fix.  I also add a new jtreg
>> test to exercise the Console and DeleteOnExitHook being initialized during
>> application shutdown.
>>
>> Alan,
>>  I considered your suggestion to make Shutdown#add method to return a
>> boolean instead of checking the state.  I am concerned that if the caller
>> didn't check the return value and handle properly, it would be harder to
>> catch the problem.  So I keep it to check the state and throw
>> IllegalStateException.
>>
>> Thanks
>> Mandy
>>
>>