sub logger_class
{
  my $self = shift;
  my $set = 0;

  # was a (new?) class passed in?
  $self->{__PACKAGE__ . ':logger_class'} = shift and $set++ if @_;

  # if we don't have one, construct the default.
  unless (exists $self->{__PACKAGE__ . ':logger_class'})
  {
    $self->{__PACKAGE__ . ':logger_class'} = ref(shift) . '::Debug';
    $set++;
  }

  # if it changed, do any configuration needed.
  if ($set)
  {
    # load the class, etc.
  }

  # done - return it.
  $self->{__PACKAGE__ . ':logger_class'};
}