From: Gordon Thiesfeld <gthiesfeld@...>
Date: 2007-08-25T23:35:03+09:00
Subject: Re: Logging object.

On Aug 25, 8:22 am, Jeremy Wells <jwe...@servalsystems.co.uk> wrote:
> tobyclem...@gmail.com wrote:
> > Hi,
>
> > Can anyone suggest the best way to pass a Logger object around between
> > all the classes in an application?
>
> > Currently I have it set in a constant in the top-level but I don't
> > feel that this is the best way to do it as it couples the code in each
> > of my classes to the current implementation and makes it difficult for
> > me to reuse the code elsewhere without first setting up a logger
> > instance of the same name.


I had a similar need, but I also needed a way to send emails from
different classes as well, so the code started getting a lot of extra
junk in it.  I solved it by borrowing some code from zenspider's
autotest.  I took his idea of hooks and plugins and extracted it into
a mixin, so I can include it in all of my classes.

So in your toplevel file you might have:

require 'hookable'
require 'foo'
require 'logging'
require 'email'
require 'other_plugins'

foo.rb might look like this

class Foo
  include Hookable

  def something
    hook :something_happened
  end

end

then in logging.rb, you would have:

@log = Logger.new(...)

Foo.add_hook(:something_happened){|i| @log.info "something was
called"}

Also, in the block, you have access to the object that called the
hook.
The hookable mixin code is here: http://pastie.caboo.se/90899

regards,

Gordon