From: dblack@...
Date: 2006-09-19T23:33:55+09:00
Subject: Re: Communication between objects.

Hi --

On Tue, 19 Sep 2006, Tod wrote:

> I have been working with Ruby for a few months now and have hit upon
> something that I can't find the answer to: what does the code look like
> for passing messages back and forth between objects. Here is a specific
> example: In a web application (I am not using ROR) I have a CGI object
> and an object whose superclass is Active Record.  The CGI object
> receives some params from POST and makes them available to the Active
> Record object. Not surprisingly, the Active Record object does some
> work with a database. Here's where I am stumped how do I have the
> ActiveRecord Object tell the CGI object that it is done working with
> the database and the CGI object may now do something else.
>
> I have made a particularly in-elegant work-around by having the ActRec
> object set a global variable to something when it is done and follow
> this with a conditional that checks to see if that global variable was
> set and if it is then the CGI object can proceed. But there has to be a
> more direct way to do this. Also, if I wanted to pass things back and
> forth between objects this would not work.
>
> I am sure the examples are out there so I must be looking in the wrong
> place or trying to call it something it is not.

I can see what kind of problem you're trying to solve, but in this
case I can't seem to see beyond:

   ar_object.do_something
   cgi_object.do_something_next

which means I'm not seeing how the program is designed.  Can you
elaborate?  It might even help to see the global variable version, so
that I can see where in the code the two objects are and why they have
to be aware of each other.


David

-- 
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org