From: Shawn Anderson <shawn42@...>
Date: 2008-05-08T16:11:35+09:00
Subject: Re: Event handling

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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/.
>
>

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