Ok, that sounds good to me. I have to admit, I did'nt know about the
possibility to register a Component with multiple services. When we started
using Windsor we used the file based XML configuration and partly do it
today. And since the ResolveAll() worked as expected, we didn't think
about registering a component this way.
The multiservice concept resolves the problem i talked about. And the need
for code changes seems not to be as big as i suspected, since in
the end the call to and the behaviour of ResolveAll() stays the same, if we
change the registration process.
Thanks for the explanation.
Am schrieb Krzysztof Koźmic <[email protected]>:
Thanks for the explanation. Actually supporting precisely this scenario
was the reason for introducing this behaviour in the first place, back in
2008. And that's because back then Windsor only supported single service
per component. So you could have had PatientTaskCalc registered either as
IPatientTask, or as ITask but not as both. So to workaround this
limitation the ResolveAll ignored what service you assigned to the
component and just looked if its assignable to the type you want.
Later on though (not sure if RC3 had it, but all releases starting with
2.0 did) we introduced concept of ForwardedHandler to allow components to
expose multiple services. That was piggy-backed a bit on top of existing
architecture at the time. In Wawel (codename for Windsor vNext) that was
rebuilt so that multi-service components are now a core concept in
Windsor.
This removes the need for the workaround since now you can be explicit
about your intention:
pContainer.Register(
Component.For().ImplementedByPatientTaskCalc>().LifeStyle.Transient);
As a sidenote, you can simplify that registration even further by relying
on scanning, like this:
container.Register(AllTypes.FromAssemblyBla().BasedOnITask>().WithService.DefaultInterface().Configure(c
=> c.Lifestyle.Transient));
You would get the same behaviour as you have now, with benefit of being
explicit.
And that implicitness of current implementation is the biggest problem
and driver for change here (mostly to accommodate massively popular
ASP.NET MVC framework with breaks SRP and is a PITA to work with, unless
this is fixed).
Looking forward to your (and others') insight on this.
On 06/03/2011 3:59 AM, [email protected] wrote:
Hi Krzysztof,
one of the scenariois where i use this is the following:
The application is extendable with any plugins. A costumer has also the
ability to extend the application with his own plugins.
The base for such plugins is a framework wich defines the architecture
and some basic interfaces and classes so that the plugins
can integrate properly. One of the reasons for user defined plugins are
Task that could be started by hand or in a chronological
order at defined points in time. So we provide Task interfaces for
specific parts of the application (IPatientTask, IAppointmentTask and so
on).
For any other Task not associated with a specific part of the
application, simply the ITask interface could be used. During startup the
app searches
for plugins and loads them. After that all plugins are being searched for
known interface implementations to register them with the container.
In short it does something like this:
pContainer.Register(
Component.For().ImplementedBy().Named("p_calc").LifeStyle.Is(Castle.Core.LifestyleType.Transient)
);
pContainer.Register(
Component.For().ImplementedByPatientTaskMidnight>().Named("p_midnight").LifeStyle.Is(Castle.Core.LifestyleType.Transient)
);
pContainer.Register(
Component.ForIAppointmentTask>().ImplementedByAppointmentTaskMonth>().Named("a_month").LifeStyle.Is(Castle.Core.LifestyleType.Transient)
);
pContainer.Register(
Component.ForIAppointmentTask>().ImplementedByAppointmentTaskBack>().Named("a_back").LifeStyle.Is(Castle.Core.LifestyleType.Transient)
);
In the application the user can now start a Task or can define, when a
specific Task should start automatically etc. If i want a specific Task,
i ask the container:
IPatientTask[] pTasksP = pContainer.ResolveAllIPatientTask>(); //2
IAppointmentTask[] pTasksA = pContainer.ResolveAllIAppointmentTask>(); //2
To get all the registered Tasks, i ask the container:
ITask[] pAllT = pContainer.ResolveAll(); ///all 4
So, in the end for this i need the current behaviour or i have to change
the current application code. Sure there are a lot of other
ways to accomplish this but we decided years ago to do it that way,
because it is simple and it is there :-)
There are other parts, where we use the same approach for instance for
text and document generation etc.
Regards
Am schrieb Krzysztof Koźmic [email protected]>:
> That's a fair point and that's precisely why I started this thread and
asked for feedback.
>
> So can you shed some more light on the context in which you're
depending on current behaviour and why/if alternative approach (just
registering your components with the service you ResolveAll) would or
would not be feasable.
>
>
>
> I also don't want to derail this thread but i would also be interested
in hearing you scenario in which you're using RemoveComponent. Perhaps if
you could start another thread to discuss that, that would be great.
>
>
>
> Krzysztof
>
>
>
> On 04/03/2011 11:49 PM, [email protected] wrote:
>
>
> Jason, that may all be true, but I want to use the container as is and
don't want to rethink and rework thinks from release to release. Now i
use ResolveAll and
>
> want it to return all components implementing a specific service no
matter for what else they are registered. Next time i have to build
something new to do this.
>
> Now i use RemoveComponent. Next release it is not available anymore and
i have again to build something new. I don't know , i thought i simply
could use the lib
>
> to simplify my work where i have enough other things to think about.
>
>
>
> Am schrieb Jason Meckley [email protected]>:
>
> > Handler selectors are not a work around, they are how handler
selection should be done. the recommendation on the table fixes a subtle,
implicit bug. creating yet another method on IWindsorContainer doesn't
solve the problem, it solves the symptom.
>
> >
>
> >
>
> >
>
> >
>
> >
>
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