Comments on: Observer and Singleton design patterns in Ruby

By: anon

anon — Thu, 29 Mar 2012 06:48:38 +0000

Bad example with BankAccount. Now, the BankAccount class depends on EmailNotifier, SMSNotifier. It cannot function unless those classes exist. You’ve created tight-coupled-ness.

By: Nehal Kumar

Nehal Kumar — Mon, 27 Jun 2011 10:31:12 +0000

Hi, I want to know how to linkthe observer of one model to another model in Rails?
I would also like to know how to pass random variables between two models.
Thanks
P.S. I am a novice on Ruby on Rails and I have a lot of small doubts. Your help would be appreciated.

By: observer application

observer application — Sun, 04 Apr 2010 02:11:22 +0000

[...] apollo app. I decided to … with Apollo and created an application that allows me to keep an …Observer and Singleton design patterns in Ruby – Khaled …Observer and Singleton design patterns in Ruby. This is my first article in http: … Observer and [...]

By: Evgeniy Dolzhenko

Evgeniy Dolzhenko — Thu, 04 Mar 2010 07:36:14 +0000

I really dig your blog, and the “cool Ruby questions” series specifically.

Sorry if that sounds like total dumbass nitpicking, but a few whitespaces in the first code sample won’t hurt IMO:

@owner, @balance = owner, amount ... @balance -= amount if (@balance - amount) > 0

By: gui_maranhao

gui_maranhao — Wed, 03 Mar 2010 18:07:16 +0000

in my last post, the method’s name was:
def after_something
…
end

thanks

By: gui_maranhao

gui_maranhao — Wed, 03 Mar 2010 18:00:42 +0000

Khelll,

In order to reduce the complexity of my observers, I would like to know if it is possible for my Observer to observe specific methods (not just the models) of my models, like this:
def after_
…
end

Thanks, guilherme

By: khelll

khelll — Mon, 01 Mar 2010 17:02:59 +0000

No worries, always try to make your code readable by breaking it to parts that makes sense. Observers are cool place for callbacks and complex code related to them.

By: gui_maranhao

gui_maranhao — Mon, 01 Mar 2010 17:01:17 +0000

In my last post I wrote: “I’ve answered my question!”. SORRY, it should have been: “YOU’ve answered my question!”

By: gui_maranhao

gui_maranhao — Mon, 01 Mar 2010 16:55:36 +0000

Thanks,

When I mentioned “actions” I did not mean controller’s actions, I meant inputs in my db to register loggs and things like that, sorry.
I also use them as callbacks to model methods. I’ve answered my question!

thanks again

By: khelll

khelll — Mon, 01 Mar 2010 16:41:25 +0000

@gui_maranhao, Rails Observers don't work with controller actions, instead with model callbacks. Anyway I prefer observers for callbacks to normal model methods, specially when the code base becomes complex.