Igor Fedorenko wrote:
> I am not sure if I need lifecycle extensions as such. Block and its
> security interceptor are tightly coupled but managed as two separate
> units. This could be a problem but might as well be ok -- I did not
> think much about it yet. Anyways, I'll keep extensions in mind.
>
> Btw, can I implement watchdog service using these lifecycle
> extensions? Watchdog => periodically checks if a block is alive and if
> it is not executes some recovery procedure.
No problem.
1. create a lifecycle interface e.g. Observable (or whatever) that
includes the operation(s) to be invoked on the target component
public interface Observable
{
// operation returns if it is alive - or whatever
void observe();
}
2. create a component that will handler the objervation of the
observable - for this you would implement the Creator interface because
you concerned with monitoriing of a component (block) over its entire
lifetime.
public class ObserverExtension implements Creator
{
public void create( Object object, Context context )
{
// the object passed in is the component and the
// context object contains whatever you declared that
// the extension needs
// maybe setup a thread at this point the periodically
// pings the object and return - the runnable object you
// create would include the maintenance procedures
if( object instanceof Observable )
{
// setup the monitor
}
else
{
// complain to the container
}
}
public void destroy( Object object, Context context )
{
// this is where you would terminate the thread and
// relase resources because the object is being destroyed
}
}
The excalibur/container package only contains the container independent
aspects of this model - namely the interfaces Creator and Accessor
together with a couple of minimal abastract classes.
If you use Merlin for this then you extension will be treated as a first
class component (depedencies, context, cofiguration, even its own
lifecyle extensions).
Cheers, Steve.
>
>
> Stephen McConnell wrote:
>
>>
>>
>> Igor Fedorenko wrote:
>>
>>> Ok, I will post a patch for cvs HEAD later this coming week.
>>>
>>> Btw, this stuff needs a little bit more from interceptor support then I
>>> originally thought. Specifically jaas interceptor must access BlockInfo
>>> somehow my guess through "Contextualizable" interface. It also needs to
>>> be Initializable/Startable. In other words, interceptors need lifecycle
>>> support as any other block (interceptor's lifecycle is couple with
>>> lifecycle of its block, so implementation might get tricky). Should I
>>> resubmit "interceptor patch" with this added functionality or should I
>>> wait for you to check interceptor support in and extend it after that?
>>
>>
>>
>> You may want to take a look at the lifecycle extensions work that has
>> been completed between the Merlin and Fortress projects. The Merlin
>> implementation provides complete support for the establishment of
>> extensions that are themselves components and as such receive full
>> lifecycle handling prior to their application towards a component
>> (block).
>>
>> http://jakarta.apache.org/avalon/excalibur/container/extension.html
>>
>> Cheers, Steve.
>>
>
>
--
Stephen J. McConnell
OSM SARL
digital products for a global economy
mailto:[EMAIL PROTECTED]
http://www.osm.net
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