use Perl

• Inheritance is not the answer. (Score:2)

  by brian_d_foy (44)

  What's really broken is that people think you need to inherit everything. In your example, it looks like you have a cart that should have things, not inherit things. I know this lame example shows up in a lot of Java books, but it's the wrong use for inheritance. They usually pull this stuff out to explain decorators, too, which is a pattern that is almost never needed for the example given.
  
  There's no reason that any of those things should have an Is-A relationship. You need a cart that contains other disti
  • Re: (Score:1)

    by jk2addict (4946)

    There's no reason that any of those things should have an Is-A relationship. You need a cart that contains other distinct objects,

    That's not exactly true in .NET. The Cart whould returns a strongly type collection of CartItems, not a mishmash of Object that then have to be inspect just to see what they are. And I don't understand that statement about no reason for IS-A. A CartItem IS a part...period. 100% percent of the time. You can't buy anything that's not a part...but I digress... Well sure, you coul
    • Re:Inheritance is not the answer. (Score:2)

      by brian_d_foy (44) <brian.d.foy@gmail.com> on 2007.06.05 10:37 (#55440) Homepage Journal

      Inheritance is only one way to look at that. An orderable item can be an object that contains a part along with an order description, coupon, etc. Those HAS-A relations, along with appropriate dispatching, don't need inheritance.
      
      Like I said, inheritance is beat into people's heads, so they think in terms of it when in reality the world doesn't operate that way.

      Reply to This

      Parent