From: Jamis Buck <jgb3@...>
Date: 2004-10-07T22:01:42+09:00
Subject: Re: Ruby-esque Inversion of Control

Brian Candler wrote:

> It doesn't work for all cases - e.g. where you want to change logging so
> that one component gets a different logger. In that particular example, you
> could rebuild the dependency information to allow for it:

[snip]

In Copland, I have a LogFactory service which intelligently manages the 
instantiation of logger instances. It can be configured to specify a 
differently-configured logger for different services. This requires that 
some additional information be passed to the constructor block, such as 
the metadata about the service being constructed, so that the LogFactory 
can be given enough information to configure the new logger correctly.

Something (roughly) like this:

   container.register( :service ) { |c,meta|
     svc = NewService.new
     svc.logger = c.log_factory.get( meta )
     svc
   }

- Jamis

-- 
Jamis Buck
jgb3@email.byu.edu
http://www.jamisbuck.org/jamis