Suppose a company has two types of workers working for them - HourlyEmployee and FullTimeEmployee. The hourly employees are paid on hourly basis and they work 40 hours a week whereas, full time employees are paid on monthly basis. Given the below code implementations for HourlyEmployee and FullTimeEmployee class and a client program EmployeeTest class that is a client of HourlyEmployee and FullTimeEmployee, evaluate code design to check whether the design follows Open-Close and Liskov Substitution Principle. Your argument should provide appropriate explanation for whether these design principles are followed or violated. If your evaluation states that the given code design violates either or both of the design principles, explain what needs to be done in terms of the changing the design. Provide a class diagram of the improved design.

public interface Employee

{

//this is an empty interface with no methods.

}

//SalariedEmployee represents a fulltime employee

public class FullTimeEmployee implements Employee

{

private int annualSalary;

public FullTimeEmployee(int sal)

{

annualSalary = sal;

}

public double salaryFullTimeEmployee()

{

return annualSalary/12;

}

}

public class HourlyWageEmployee implements Employee

{

//hourly wage rate

private int wageRate;

public HourlyWageEmployee(double wage)

{

wageRate = wage;

}

//salary( ) method returns the weekly salary

//

public int salaryHourlyWageEmployee()

{

return 40 * wageRate;

}

}

//client program using the Employee types

public class EmployeeTest

{

public double returnSalary(Employee e )

{

if(e instanceof FullTimeEmployee)

{

FullTimeEmployee s = (FullTimeEmployee) e;

return s.salaryFullTimeEmployee();

}

else

{

HourlyWageEmployee h = (HourlyWageEmployee) e;

return h.salaryHourlyWageEmployee();

}

}

}