General talk about software patterns

[Al Boldi <a1426z AT gawab.com>]

Messaging Design Pattern wrote:
> 1) No. Observer and messaging are two separate design patterns (concepts).

Separate concepts yes, but both could conceivably be used to implement the 
same project.  When would we prefer the ODP over the MDP and vice/versa.

The reason I am questioning is that I see many developers picking the wrong 
pattern for their implementation rendering the result a failure.  What we 
need are clear instructions of when the MDP is applicable and when it is not.

> In terms of performance and resource usage, MDP is very light and
> efficient. Keep in mind that messaging (core functionality) can be
> implemented with a single messaging interface:
>
> public interface JtInterface  {
> /**
>   * Jt messaging interface used for the implementation
>   * of the messaging design pattern.
>   * Process an input message and return a reply (output message)
>   */
>
>   Object processMessage (Object message);
> }

Yes, both the interface and the concept itself look simple, yet when trying 
to 
implement this interface it quickly mushrooms into a multi-threaded endeavor.

What is needed is more detail about the design pattern specifics, i.e. 
associated sub-patterns needed to guide the developer to a successful 
implementation.


Thanks!

--
Al