Notes

1.
public abstract class Employee {

private final String firstName;
private final String lastName;
private final String socialSecurityNumber;

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

}
public String getFirstName()
{
return firstName;
}
public String getLastName()
{
return lastName;

}
public String getSocialSecurityNumber()
{
return socialSecurityNumber;
}
@Override
public String toString()
{
return String.format("%s %s%nsocial security number : %s",
getFirstName(),getLastName(),getSocialSecurityNumber());
}
public abstract double earnings();
}
2.
public class SalariedEmployee extends Employee {

private double weeklySalary;

public SalariedEmployee(String firstName, String lastName, String socialSecurityNumber, double weeklySalary) {
super(firstName, lastName, socialSecurityNumber);
if (weeklySalary < 0.0) {
throw new IllegalArgumentException(
"Weekly salary must be >= 0.0");
}

this.weeklySalary = weeklySalary;
}

public void setWeeklySalary(double weeklySalary) {
if (weeklySalary < 0.0) {
throw new IllegalArgumentException(
"Weekly salary must be >= 0.0");
}

this.weeklySalary = weeklySalary;
}

public double getWeeklySalary() {
return weeklySalary;
}

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

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

}
3.
public class HourlyEmployee extends Employee {

private double wage;
private double hours;

public HourlyEmployee(String firstName, String lastName,
String socialSecurityNumber, double wage, double hours) {
super(firstName, lastName, socialSecurityNumber);
if (wage < 0.0) // validate wage
{
throw new IllegalArgumentException(
"Hourly wage must be >= 0.0");
}

if ((hours < 0.0) || (hours > 168.0)) // validate hours
{
throw new IllegalArgumentException(
"Hours worked must be >= 0.0 and <= 168.0");
}

this.wage = wage;
this.hours = hours;
}

public void setWage(double wage) {
if (wage < 0.0) // validate wage
{
throw new IllegalArgumentException(
"Hourly wage must be >= 0.0");
}

this.wage = wage;
}

public double getWage() {
return wage;
}

public void setHours(double hours) {
if ((hours < 0.0) || (hours > 168.0)) // validate hours

throw new IllegalArgumentException(
"Hours worked must be >= 0.0 and <= 168.0");

this.hours = hours;
}

// return hours worked
public double getHours() {
return hours;
}

@Override
public double earnings() {
if (getHours() <= 40) // no overtime
{
return getWage() * getHours();
} else {
return 40 * getWage() + (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());
}
}
4.
public class CommissionEmployee extends Employee {

private double grossSales; // gross weekly sales
private double commissionRate; // commission percentage

public CommissionEmployee(String firstName, String lastName,
String socialSecurityNumber, double grossSales,
double commissionRate) {
super(firstName, lastName, socialSecurityNumber);

if (commissionRate <= 0.0 || commissionRate >= 1.0) // validate
{
throw new IllegalArgumentException(
"Commission rate must be > 0.0 and < 1.0");
}

if (grossSales < 0.0) // validate
{
throw new IllegalArgumentException("Gross sales must be >= 0.0");
}
this.grossSales = grossSales;
this.commissionRate = commissionRate;
}

public void setGrossSales(double grossSales) {
if (grossSales < 0.0) // validate
{
throw new IllegalArgumentException("Gross sales must be >= 0.0");
}

this.grossSales = grossSales;
}

public double getGrossSales() {
return grossSales;
}

public void setCommissionRate(double commissionRate) {
if (commissionRate <= 0.0 || commissionRate >= 1.0) // validate
{
throw new IllegalArgumentException(
"Commission rate must be > 0.0 and < 1.0");
}

this.commissionRate = commissionRate;
}

public double getCommissionRate() {
return commissionRate;
}

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

@Override
public String toString() {
return String.format("%s: %s%n%s: $%,.2f; %s: %.2f",
"commission employee", super.toString(),
"gross sales", getGrossSales(),
"commission rate", getCommissionRate());
}
}
5.
public class BasePlusCommissionEmployee extends CommissionEmployee {

private double baseSalary; // base salary per week

public BasePlusCommissionEmployee(String firstName, String lastName,
String socialSecurityNumber, double grossSales,
double commissionRate, double baseSalary) {
super(firstName, lastName, socialSecurityNumber,
grossSales, commissionRate);

if (baseSalary < 0.0) // validate baseSalary
{
throw new IllegalArgumentException("Base salary must be >= 0.0");
}

this.baseSalary = baseSalary;
}

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

public double getBaseSalary() {
return baseSalary;
}

@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());

}
}

6.
public class PayrollSystemTest {

public static void main(String[] args) {
SalariedEmployee salariedEmployee
= new SalariedEmployee("John", "Smith", "111-11-1111", 800.00);
HourlyEmployee hourlyEmployee
= new HourlyEmployee("Karen", "Price", "222-22-2222", 16.75, 40);
CommissionEmployee commissionEmployee
= new CommissionEmployee(
"Sue", "Jones", "333-33-3333", 10000, .06);
BasePlusCommissionEmployee basePlusCommissionEmployee
= new BasePlusCommissionEmployee(
"Bob", "Lewis", "444-44-4444", 5000, .04, 300);
System.out.println("Employees processed individually:");

System.out.printf("%n%s%n%s: $%,.2f%n%n",
salariedEmployee, "earned", salariedEmployee.earnings());
System.out.printf("%s%n%s: $%,.2f%n%n",
hourlyEmployee, "earned", hourlyEmployee.earnings());
System.out.printf("%s%n%s: $%,.2f%n%n",
commissionEmployee, "earned", commissionEmployee.earnings());
System.out.printf("%s%n%s: $%,.2f%n%n",
basePlusCommissionEmployee,
"earned", basePlusCommissionEmployee.earnings());
Employee[] employees = new Employee[4];

employees[0] = salariedEmployee;
employees[1] = hourlyEmployee;
employees[2] = commissionEmployee;
employees[3] = basePlusCommissionEmployee;
System.out.printf("Employees processed polymorphically:%n%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());
}
for (int j = 0; j < employees.length; j++)
System.out.printf("Employee %d is a %s%n", j,
employees[j].getClass().getName());
}


}