Refactoring Tips - Tip 5

Refactoring Tips - Tip 5

Tip 5

Always Programme for interface/abstract than concrete classes, Which will gives the option for extension, loose coupling and plugin.

This will also be in line with one of the design principle - LSP(Liskov's substitution Principle) - in simple word it summarises that, Every subclass should be substitutable for a base class.

For eg: if i have to write a data persistent class.

Bad practice

public class SqlRepository
{
 void Crete(parameters)
 {
   //Logic to get the data...
 }
 void Delete(id)
 {
  //Logic to delete the data based on the id
 }
 //Some more specific methods
}

Good practice

public interface IRepository
{
  void Create(object);
  void Delete(id);
  //Some more methods...
}

public class SqlRepository :IRepository
{
  void Crete(parameters)
  {
   //Logic to get the data...
  }
  void Delete(id)
 {
  //Logic to delete the data based on the id
 }

 //Some more specific methods

}

This arrangement gives us the flexibility that tomorrow, if i want to write a repostory for some other store then also i can write without much impact with the exisiting clients.

I hope this helps!.

Regards,
-Vinayak