Thanks Stephen,
I've already started implementing something like this using
commons-pool, and your recommendation helps crystallize my thoughts
considerably.
Regards,
Peter
On Wed, 2004-01-07 at 17:36, Stephen McConnell wrote:
> Peter Courcoux wrote:
> > Hi all,
> >
> > I have a requirement for pooling components and am using a version of
> > merlin which is a couple of months old. I seem to recall that the pooled
> > lifestyle handling was switched off. Is this still the case and if so,
> > is there a recommended pattern for providing pooled components?
>
> Correct.
>
> Based on discussion on this subject over the last six months - my
> conclusion is that the related semantics area for all intensive purposes
> a rather gray area. This is primarily related to strong relationship
> between pool and the components it manages (in particular things like
> recycling strategies), and subtle relationships between a component that
> is using a pooled component and the pool itself.
>
> My recommendation concerning pooled components is:
>
> 1. declare a factory service with formal instance acquisition
> and release methods .. e.g.
>
> public interface WidgetPool
> {
> Widget aquireWidget();
> void releaseWidget( Widget widget );
> }
>
> 2. implement a component the exposes the pooled interface as a
> service using whatever pool technology you like (excalibur,
> commons pool, etc.)
>
> /**
> * @avalon.service type="WidgetPool"
> */
> public class DefaultWidgetPool implements WidgetPool
> {
> ...
> }
>
> 3. for consumer components, declare a dependency on the pool
> directly
>
> /**
> * @avalon.dependency key="pool" type="WidgetPool"
> */
> public void service( ServiceManager manager )
> throws ServiceException
> {
> m_pool = (WidgetPool) manager.lookup( "pool" );
> }
>
> Using this approach you component implementation is crystal clear about
> the assumptions concerning the WidgetPool and your implementation can be
> much more strict about acquisition and release policies.
>
> Hope that helps.
>
> Cheers, Stephen.
>
>
> >
> > I will be grateful for any thoughts.
> >
> > Many thanks.
> >
> > Peter
--
Peter Courcoux <[EMAIL PROTECTED]>
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