Active Objects

From: Nimmi Srivastav (nimmi_srivastav_at_yahoo.com)
Date: 06/04/04 

Date: 3 Jun 2004 17:14:45 -0700

I am trying to follow the Active Object design pattern, as described
in the "Pattern-oriented software architecture, Volume 2" book
(Douglas Schmidt et al). I am somewhat confused by the various
"Participants" in the design pattern, as shown on Pg 374. The Client
invokes a method on a Proxy, but obtains its result from the Future.
Does this mean that the client is aware of the Future? Also, since the
Servant implements the active object, why is there a need for the
MethodRequest? Why can't the Proxy or the Scheduler directly execute
the method on the Servant? Also, do we really need a Scheduler? All we
want to do is to defer the execution of the invoked method till the
active object thread is scheduled. We are not doing any sophisticated
scheduling.

Again, how does the Active Object handle synchronous method calls,
especially one in which the Client is using the value returned by the
Client? I am asking this question because the request will get
enqueued in the ActivationQueue and will not be processed immediately.
The Proxy, on the other hand, will return control to the Client
immediately.

Can someone please suggest some simpler implementation?

Thanks,
Nimmi