RE: Fortress and Events

> From: Daniel Krieg [mailto:[email protected]]
> 
> Berin,
> 
> Thanks for your reply.  I have some followup questions that you
> may be able to address.  The application I am developing will
> be a server app hosted within Phoenix.  Several of the sub-system
> components that I am developing are an assembly/composition of
> smaller services/components.  These sub-system components are
> unlikely to change configuration often, however with respect 
> to Phoenix,
> the assembly of these Blocks (sub-system components) will likely
> change...(Does this make any sense???)

I think so.


> I think it is more appropriate to implement these sub-system
> components using Fortress Container and assemble them together
> as Phoenix Blocks.  One requirement I have is that these components
> take advantage of the SEDA architecture within Excalibur Events.
> I would like to use CommandManager to handle dispatching of
> Commands.  Does the DefaultContainer do this implicitly?  What
> alternatives are available?

The DefaultContainer has a reference to the CommandManager's Sink.
It passes a reference to that Sink via the Context at this time.
The key is in the ContainerConstants interface AFAIR.


> Is it more appropriate to define my sub-system components by
> extension or containment of the Fortress DefaultContainer?

It depends on what you want to do.  If you are merely *using*
the Fortress DefaultContainer, then contain it.  If you want
to change some aspects of how it configures information, then
extend it.

In most cases, I suggest containment.

> If I have a component A and component B needs to send a
> Command to component A, and that Command needs access to
> a service held within component A in order to execute, what is
> the proper IOC approach? (...Again, make any sense???).

Let's see if I can refrase this:

Component B wants to perform an asynchronous operation on
Component A.

In order to make this happen, the Command needs a reference
to the other component.  There are two ways you can achieve
that:

1) Pass in the ServiceManager to the Command, and let the Command
   lookup Component A.

2) Pass in a reference to Component A.

The tradeoffs are:

Option 1 allows you to work with components of any lifestyle,
making the lookup/release cycle all within one context.

Option 2 forces you to work with "ThreadSafe" components, or
provide complicated and error prone lookup/release logic.

Either approach will allow you to perform whatever you need
to do.