http://www.perlmonks.org?node_id=317562


in reply to Re: Often Overlooked OO Programming Guidelines
in thread Often Overlooked OO Programming Guidelines

Yes, you're correct. I used a rotten example. Here's a clearer example. A corporate customer is assigned to a company, which has an office which has a manager.

  my $manager = $customer->company->office->manager;

Later on, we realize that this is a bad class heirarchy and the customer should belong to an office and the company is superflous to this, but we've hardcoded a chain of method calls and this makes life difficult. What if we had done this:

sub Customer::manager { my $self = shift; return $self->{delegates}{company}->manager; } sub Company::manager { my $self = shift; return $self->{delegates}{office}->manager; } sub Office::manager { my $self = shift; return $self->{delegates}{manager}; }

Now the fix is easy, when we want to drop the Company class reference in the Customer object.

sub Customer::manager { my $self = shift; # return $self->{delegates}{company}->manager return $self->{delegates}{office}->manager; }

Cheers,
Ovid

New address of my CGI Course.