From: George Malamidis <george@...>
Date: 2008-05-08T17:26:01+09:00
Subject: Re: Event handling

Hello,

You can also have listeners register blocks to certain events instead  
of implementing a specific method like "sound_event". That way you  
publisher can be more decoupled from the listeners' implementation.  
Have a look at http://nutrun.com/weblog/event-registry/

Thanks,
George

On 8 May 2008, at 08:11,  wrote:

> This seems like a decent approach; maintaining a list of listeners and
> notifying them.  A few notes:
> for i in 0...@listeners.length
>     @listeners[i].sound_event('MHOEEEE')
> end
>
> Closures or blocks in ruby are perfect for this:
> @listeners.each do |listener|
>      listener.sound_event 'MHOEEEE'
> end
>
> to get cool eventing like:
>
> @car.when :crashing do
>    jump_out
> end
> I recommend looking at Publisher:
> http://rubyforge.org/projects/atomicobjectrb/
>
>
> On Wed, May 7, 2008 at 10:42 PM, Aa Aa <banditgsf600n@hotmail.com>  
> wrote:
>
>> Oke, I've implemented the following observer/listener program:
>>
>> class Cow
>> def initialize
>>   @listeners = Array.new
>> end
>>
>> def add_listener(listener)
>>   raise ArgumentError if !listener.respond_to?(:sound_event) &&
>> !listeners.include?(listener)
>>   @listeners << listener
>> end
>>
>> def remove_listener(listener)
>>   @listeners.delete(listener)
>> end
>>
>> def notify_listeners
>>   for i in 0...@listeners.length
>>     @listeners[i].sound_event('MHOEEEE')
>>   end
>> end
>>
>> def be_happy
>>   notify_listeners
>> end
>> end
>>
>> class Program
>> def sound_event(value)
>>   puts value
>> end
>>
>> def start
>>   cow = Cow.new
>>   cow.add_listener(self)
>>   cow.be_happy
>> end
>> end
>>
>> Program.new.start
>>
>> Is this an appropriate way of doing event handling in ruby?
>> --
>> Posted via http://www.ruby-forum.com/.
>>
>>