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From Stephen McConnell <mcconn...@osm.net>
Subject Re: [A5] Activity Package
Date Sun, 16 Jun 2002 06:58:02 GMT


Peter Donald wrote:

> We could also kill Executable interface. Useful as it is - it usuallly 
> not considered lifecycle stuff. 


I use the Executable interface to signal an objects ability to do 
something between *initialize* and *dispose* which comes in very handy 
for execution of minmal component test or when you want a component to 
act as a function.  I consider Executable and Startable as incompatable 
at the container level - i.e. a container should not attempt to execute 
and start a component.  However, I have several occurance of a component 
implementing both - the container will normally invoke start unless 
explicity directed to run the component as a function (Executable).

Cheers, Steve.


>
>
> At 11:27 AM 6/15/2002 -0400, you wrote:
>
>> This houses the Initializable, Startable, and Resumable interfaces.
>>
>> I'm pretty happy with it, but we should consider a couple of points:
>>
>> 1) are Initializable and Disposable separate concerns?  If so we should
>>    split the interface.  If not, then we will leave it alone
>> 2) We have determined that start() and stop() apply to the same concern
>>    of an active component.  We should explicitly state that the
>> Startable
>>    interface is designed to let an active component know when they can
>>    start background execution threads and when to stop them safely.
>>    We should also state as a contract that stop()ing a component
>>    MUST NOT FAIL!  This preculdes the necessity of an exception at this
>>    point.  It also makes it the responsibility of the component to clean
>>    up any expensive resources like threads and sockets successfully.
>>    - The container has no way of nowing what system resources a
>> component
>>      takes if they are not retrieved from other components.
>>
>>
>> "They that give up essential liberty to obtain a little temporary safety
>>  deserve neither liberty nor safety."
>>                 - Benjamin Franklin
>>
>>
>> -- 
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>
>
> Cheers,
>
> Peter Donald
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> "Faced with the choice between changing one's mind,
> and proving that there is no need to do so - almost
> everyone gets busy on the proof."
>              - John Kenneth Galbraith
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
> -- 
> To unsubscribe, e-mail:   
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>

-- 

Stephen J. McConnell

OSM SARL
digital products for a global economy
mailto:mcconnell@osm.net
http://www.osm.net




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