Question

I have the following object model:

class CheckoutAd{
  int AdId;
  int ImpressionCap;
  int ClickCap;
  int ConversionCap;
  // ...
}

class SiteAd{
  int AdId;
  int ImpressionCap;
  int ClickCap;
  //...
}

As you see there is duplicate code. So i decided to put the duplicate code in a base class and extend the above classes from base class as follows:

class BaseAd{
   int AdId;
   int ImpressionCap;
   int ClickCap;
} 

But then I thought about the future which there will be a MobileAd class that this base class might not be a good candidate then I would have to change it.

Should I delegate these properties instead?

How would you do it?

Should i use strategy pattern ? how would i delegate this behavior?

Answer 1

I see no duplicate code, I see a couple of classes with members with the same names and types.

Is CheckoutAd a SiteAd? (yes inherit)
Does CheckOutAd have a SiteAd? (yes aggreate)
No to both, leave them the heck alone..