Design Patterns discussion

["Prabodh Saha" <prabodhs AT ivycomptech.com>]

The point of discussion is
~~~~~~~~~~~~~~~~~~~~~~~~~~
How does Factory Method promote loosely coupled code? 

Following are some points coming to my mind. Please add to it.


1. Factory Method pattern provides a strong binding between the
   "creator" and the "product". 
   The code designer can use this fact to cluster the strongly related 
   objects together [using (Factory) Methods in the creator object] and
   decouple the client application from the strong cluster.

   Then the client code can only hold a reference to a generic
   creator object (say the root object/interface of the creators'
   class hierarchy). The actual creator can be loaded at runtime
   and get referenced by the generic-creator-reference present in the
client.

2. I have a question here, can you give me a scenerio where a "product"
   of the Factory Method pattern should be used as a creator in turn 
   (thus forming a chain which can extend), rather than having more than
   one (factory) methods in the primary creator itself ?

   I mean should we ever need n-level deep factory method structure 
   rather than one-leve deep - as discussed in GOF?
   If yes when, and if not why not ?


Regards,
Prabodh

<<attachment: winmail.dat>>