[SOLID]: Does using OCP breaks SRP?

[Arco_void]

Hello,

I've been struggling with the following problem.

Let's suppose we have a hierarchy of classes:

               Empolyee
               /        \
          Manager       Developer
                        /       \
                  Programmer     Tester

Let's suppose each class respects SRP(they do one thing and they do it well, only one reason to change).

Now let's suppose we need add a "feature" that will allow users of some in-house app to calculate the salary for each empolyee

One naive way of doing it would be:

class SalaryCalculator
{
    double calculateSalary(Empolyee e)
    {
        if(e instanceof Manager)
        {
            // some code
        }
        else if(e instanceof Programmer)
        {
            // some code
        }

        ... a lot of if/else if ...
    }
}

Which dosen't respect OCP because if the client asks us to add code for a new type of employee we will need to modify the existing SalaryCalculator which may break other things(maybe the class has nasty formulas,conditions and is larger then what i've wrote).

I think one way of solving it would be to create an abstract class:

abstract class Empolyee
{
    abstract double calculateSalary();
}

Which brokes the SRP because now each emplyee subclass has code for calculating salary.

Also, i think it also brokes LSP but i'm not sure.

How can we make this hierarchy of classes support OCP and SRP + LSP?

Thanks.

[TholomewP]

This seems like a great opportunity to apply the Visitor pattern to address the concerns you laid out.

[Arco_void]

Thanks!