A company pays its employees on a weekly basis. The employees are of four types: Salaried employees are paid a fixed weekly salary regardless of the number of hours worked, hourly employees are paid by the hour and receive “time-and-a-half” overtime pay (i.e., 1.5 times their hourly salary rate) for all hours worked in excess of 40 hours, commission employees are paid a percentage of their sales and base-salaried-commission-employees receive a base salary plus a percentage of their sales. For the current pay period, the company has decided to reward salaried-commission employees by adding 10% to their base salaries. The company wants you to write an application that performs its payroll calculations polymorphically. Use abstract class Employee to represent the general concept of an employee. The classes that extend Employee are SalariedEmployee, CommissionEmployee and Hourly-Employee. Class BasePlusCommissionEmployee which extends CommissionEmployee represents the last employee type.

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
public abstract class Employee {
  private String firstName;
  private String lastName;
   private String socialSecurityNumber;

    public Employee(String firstName, String lastName, String ssn) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.socialSecurityNumber = ssn;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getSocialSecurityNumber() {
        return socialSecurityNumber;
    }

    public void setSocialSecurityNumber(String ssn) {
        this.socialSecurityNumber = ssn;
    }
  
    // abstract method overridden by concrete subclasses        
    public abstract double earnings(); // no implementation here
    // end abstract class Employee
     
    @Override
    public String toString(){
        return String.format("%s %s ssn: %s", getFirstName(), getLastName(), getSocialSecurityNumber());
    }
}

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
public class HourlyEmployee extends Employee{
  private double wage; //wage per hour
  private double hours;// hours worked for week

    public HourlyEmployee(String firstName, String lastName, String ssn, double hours, double  wage) {
        super(firstName, lastName, ssn);
        this.setHours(hours);
        this.setWage(wage);
       
    }

    public double getWage() {
        return wage;
    }

    public void setWage(double hourlyWage) {
        if(hourlyWage >= 0.0){
            this.wage = hourlyWage;
        }else
            throw  new IllegalArgumentException("HourLY Wage must be >=0.0");
    }
   

    public double getHours() {
        return hours;
    }

    public void setHours(double hourWorked) {
        if(hourWorked >= 0.0){
           this.hours = hourWorked;
        }else
            throw new IllegalArgumentException("Hour must be >=0.0 and <=168"); //work hour per week 7*24hrs
    }

    @Override
    public double earnings() {
        if(getHours() <= 40){
            return getWage()*getHours();
        }else{
            return getWage()*getHours()+(getHours()-40)*getWage()*1.5;
        }
    }

    @Override                                                            
    public String toString()                                             
    {                                                                    
         return String.format( "hourly employee: %s\n%s: $%,.2f; %s: %,.2f", super.toString(), "hourly wage" , getWage(), "hours worked", getHours() );
    }
}

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
// SalariedEmployee concrete class extends abstract class Employee.
public class SalariedEmployee extends Employee{

    private double weeklySalary; 

    public SalariedEmployee(String firstName, String lastName, String ssn, double salary) {
        super(firstName, lastName, ssn);
        
        this.setWeeklySalary(salary);
    }
    
    public double getWeeklySalary() {
        return weeklySalary;
    }

    public void setWeeklySalary(double salary) {
        if(salary >= 0.0){
            this.weeklySalary = salary;
        }else 
            throw new IllegalArgumentException("Weekly Salary Must be >= 0.0");
    }

    @Override
    public double earnings() {
        return  getWeeklySalary();
    }

    @Override
    public String toString(){
        return String.format("salaried employee: %s\n%s: $%,.2f", super.toString(), "weekly salary" , getWeeklySalary());
    }
}

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
public class CommissionEmployee extends Employee{
    private double grossSales;
    private double  commissionRate;

    public CommissionEmployee(String firstName, String lastName, String ssn, double sales, double rate) {
        super(firstName, lastName, ssn);
        this.setCommissionRate(rate);
        this.setGrossSales(sales);
    }

    public double getGrossSales() {
        return grossSales;
    }

    public void setGrossSales(double sales) {
        if(sales >= 0.0){
            this.grossSales = sales;
        }else
            throw new IllegalArgumentException("gross sales must be > 0.0");
    }

    public double getCommissionRate() {
        return commissionRate;
    }

    public void setCommissionRate(double rate) {
        if(rate > 0.0 && rate < 1.0){
            this.commissionRate = rate;
        }else
            throw  new IllegalArgumentException("Commission rate must be > 0 and < 1.0");
    }

    @Override
    public double earnings() {
        return getGrossSales()*getCommissionRate();
    }

    @Override
    public String toString(){
        return String.format( "%s: %s\n%s: $%,.2f; %s: %.2f","commission employee", super.toString(), "gross sales", getGrossSales(), "commission rate", getCommissionRate() );
    }
}

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
public class BasePlusCommissionEmployee extends CommissionEmployee{

    private double baseSalary;
    public BasePlusCommissionEmployee(String firstName, String lastName, String ssn, double sales, double rate, double salary) {
        super(firstName, lastName, ssn, sales, rate);
        this.setBaseSalary(salary);
    }

    public double getBaseSalary() {
        return baseSalary;
    }

    public void setBaseSalary(double salary) {
        if(salary >= 0.0){
            this.baseSalary = salary;
        }else
            throw new IllegalArgumentException("Base salary must be >0.0");
    }

    // calculate earnings; override method earnings in CommissionEmployee
    @Override                                                           
    public double earnings()                                                   {                                                                   
        return getBaseSalary() + super.earnings();                       
    }
                                          
    @Override                                                          
    public String toString()                                           
    {                                                                  
        return String.format( "%s %s; %s: $%,.2f",
             "base-salaried", super.toString(),                           
            "base salary", getBaseSalary() );                            
    }
   
}

• Java Code

package payroll;
/**
 *
 * @author Archangel Macsika
 */
public class TestClass {

    public static SalariedEmployee salariedEmployee;
    public static HourlyEmployee hourlyEmployee;
    public static CommissionEmployee commissionEmployee;
    public static BasePlusCommissionEmployee basePlusCommissionEmployee;

    public static void main(String[] args) {
   
        // create four-element Employee array
        Employee[] employees = new Employee[4];

        // initialize array with Employees
        employees[0] =  new SalariedEmployee("Archangel", "Macsika", "A001", 680000.00);
        employees[1] = new HourlyEmployee("Nsikak", "Imoh", "A002", 17.00, 9000);
        employees[2] =  new CommissionEmployee("John", "Doe", "A003", 9100000, 0.04);
        employees[3] = new BasePlusCommissionEmployee("Rose", "Maryland", "A004", 2120000, .03, 590000);

        System.out.println("Employees processed polymorphically:\n");

        for (Employee currentEmployee : employees) {
            System.out.println(currentEmployee); // invokes toString

            if (currentEmployee instanceof BasePlusCommissionEmployee) {

                BasePlusCommissionEmployee employee = (BasePlusCommissionEmployee) currentEmployee;

                employee.setBaseSalary(1.10 * employee.getBaseSalary());

                System.out.printf( "new base salary with 10%% increase is: $%,.2f\n",  employee.getBaseSalary());
            }

            System.out.printf( "earned $%,.2f\n\n", currentEmployee.earnings());
        }

    }

}