From: Robert Klemme <bob.news@...>
Date: 2004-07-26T17:16:57+09:00
Subject: Re: delegate also from the inside


"Florian Weber" <csshsh@structbench.com> schrieb im Newsbeitrag
news:A65539F2-DE25-11D8-8F52-000A95BD142E@structbench.com...
>
> On Jul 24, 2004, at 19:26 Uhr, Robert Klemme wrote:
>
> >
> > "Florian Weber" <csshsh@structbench.com> schrieb im Newsbeitrag
> > news:6F425BDB-DCFB-11D8-9B88-000A95BD142E@structbench.com...
> >> hi!
> >>
> >> if i use a proxy to wrap a object, is there a way to allow that calls
> >> from the wrapped object to a method in the wrapped object go via
> >> the proxy.
> >>
> >> example:
> >>
> >> proxy#foo calls object#foo calls proxy#bar calls object#bar
> >>
> >> instead of
> >>
> >> proxy#foo calls object#foo calls object#bar
> >
> > No way other than modifying the wrapped instance.  The wrapper knows
> > the
> > wrapped instance but not the other way round.  You might consider
using
> > inheritance in this case - if that works in your scenario.  Or use a
> > completely different strategy.
>
> what ways via modifications would work? besides using inheritance?

Overriding methods in the instance to wrap.  You could do that
automatically to move every method to xyz_unwrapped and subsitute it with
def xyz; wrapper.xyz; end while the wrapper invokes always
wrapped.xyz_unwrapped().  Quite complicated though.

Or you write the class to be wrapped from the start to take wrapping into
account if that's possible.  Something like

class Wrappable
  attr_accessor :wrapper

  def me; wrapper or self; end

  def some_method
    me.some_other_method
  end

  def some_other_method
    # ...
  end
end

Other than that I'd have to know the scenario in order to come up with
additional suggestions.  I guess these solutions then would not make use
of wrapping. :-)

Kind regards

    robert