General talk about software patterns

[Messaging Design Pattern <dsheppard2k AT yahoo.com>]

Ralph,

Thank you for you comments. In my opinion this is sound feedback ! The design pattern should be revised based on your comments. We'll try to address the points that you raise.

Best regards,

Ed
http://freedom.lunarpages.com/pattern/messaging.htm


--- On Thu, 2/25/10, Ralph Johnson <johnson AT cs.uiuc.edu> wrote:

From: Ralph Johnson <johnson AT cs.uiuc.edu>
Subject: Re: [patterns-discussion] Messaging Design Pattern
To: "Messaging Design Pattern" <dsheppard2k AT yahoo.com>
Cc: patterns-discussion AT cs.uiuc.edu
Date: Thursday, February 25, 2010, 11:30 AM

Every single consequence in the pattern was positive.  In other words, you only say good things about the pattern, nothing bad.  if this were true, you'd use it in every program.  Don't use any other interface except JtInterface!  Use it everywhere!

This is a common problem with patterns.  The pattern writer is so enamored with his pattern that he only wants to say good things about it.  But design is about tradeoffs.  There is a cloud with every silver lining.    If you don't understand the costs of a pattern then you don't understand the whole pattern.  And if you don't describe the costs then you sound like a used-car salesman.

I've heard this called many things.  I don't like any of those names because they can be interpreted in many ways.  i don't like Messaging, either.  Perhaps it is about parallel programming, and the pattern is to avoid shared memory and communicate only by sending messages.  Perhaps it is about distributed systems, and explores the difference between synchronous and asynchronous communication.  No, this pattern is about software architecture, and is about how to keep loose coupling between modules.  Pick a name that can't be misinterpreted.

-Ralph Johnson