I have a problem passing params into a super constructor. I'm implementing Abstraction with Inheritance. I created three classes that extends the abstract class Employee. But when I created the objects of these three classes, only one class passes the arguments correctly to the super() constructor, while the rest will return null. Here is the abstract class
public abstract class Employee {
private String firstName,lastName,SSN;
public Employee(String fName, String lName, String SSN){
this.SSN = SSN;
this.firstName = fName;
this.lastName = lName;
}
public void setFirstName(String fName){
this.firstName = firstName;
}
public void setLastName(String lName){
this.lastName = lName;
}
public void setSSN(String SSN){
this.SSN = SSN;
}
public String getSSN(){
return SSN;
}
public String getFirstName(){
return firstName;
}
public String getLastName(){
return lastName;
}
public abstract double getEarnings();
@Override
public String toString(){
return String.format("First Name: %-2s \n Last Name: %-2s \n Social Security Number: %-2s", getFirstName(), getLastName(),getSSN());
}
And here are the classes:
public class SalariedEmployee extends Employee {
private String firstName, lastName, SSN;
double weeklyPay;
public SalariedEmployee(String fName, String lName, String SSN, double wPay) {
super(fName, lName, SSN);
this.weeklyPay = wPay;
}
public void setWeeklyPay(double wPay) {
this.weeklyPay = wPay;
}
public double getWeeklyPay() {
return weeklyPay;
}
@Override
public double getEarnings() {
return getWeeklyPay();
}
@Override
public String toString() {
return String.format("%s \n Weekly Pay: %2s", super.toString(), getEarnings());
}
}
public class HourlyEmployee extends Employee{
private String firstName, lastName, SSN;
private double hourlyPay,wage;
private int hours;
public HourlyEmployee(String fName, String lName, String SSN, int hour, double hourlyPay ){
super(fName, lName, SSN);
this.hours = hour;
this.hourlyPay = hourlyPay;
}
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 getSSN() {
return SSN;
}
public void setSSN(String SSN) {
this.SSN = SSN;
}
public double getHourlyPay() {
return hourlyPay;
}
public void setHourlyPay(double hourlyPay) {
this.hourlyPay = hourlyPay;
}
public double getWage() {
return wage;
}
public void setWage(double wage) {
this.wage = wage;
}
public int getHours() {
return hours;
}
public void setHours(int hours) {
this.hours = hours;
}
@Override
public double getEarnings(){
double earnings;
if(hours> 40)
earnings = hourlyPay * 40 + ((hours-40) *hourlyPay *1.5);
else
earnings = hourlyPay * hours;
return earnings;
}
@Override
public String toString(){
return String.format("%s \n Hours worked: %s \n Salary: %s \n ", super.toString(), getHours(), getEarnings());
}
}
public class CommissionEmployee extends Employee {
private String firstName, lastName, SSN;
private double sales,commission;
public CommissionEmployee(String fName, String lName, String SSN, double sales, double commission){
super(fName, lName, SSN);
this.commission = commission;
this.sales = sales;
}
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 getSSN() {
return SSN;
}
public void setSSN(String SSN) {
this.SSN = SSN;
}
public double getSales() {
return sales;
}
public void setSales(double sales) {
this.sales = sales;
}
public double getCommission() {
double commissionRate;
if(commission >0 && commission<1)
return commission;
else
return 0;
}
public void setCommission(double commission) {
this.commission = commission;
}
@Override
public double getEarnings(){
return getCommission() * getSales();
}
@Override
public String toString(){
return String.format("%s \n Commission Rate: %s \n Salary: %s \n", super.toString(), getCommission(), getEarnings());
}
}
And Here is the TEST Class
public class EmployeeTest {
public static void main(String[] args) {
Employee salariedEmp,hourlyEmp,commissionEmp;
salariedEmp = new SalariedEmployee("Aminu", "Bishir", "11-22-33-33", 300.47);
System.out.println(printDetails(salariedEmp));
hourlyEmp = new HourlyEmployee("Musa","Sale","22-33-44-55",50,20.4);
System.out.println(printDetails(hourlyEmp));
commissionEmp = new CommissionEmployee("Muhammad","Ibrahim","33-44-55-66",20000,0.3);
System.out.print( printDetails(commissionEmp));
}
public static String printDetails(Employee emp){
return String.format("%s \n %s",emp.getClass(),emp.toString());
}
}
And this is the output I get whenever I run it:
class Abstraction.SalariedEmployee First Name: Aminu Last Name: Bishir Social Security Number: 11-22-33-33 Weekly Pay: 300.47 class Abstraction.HourlyEmployee First Name: null Last Name: null Social Security Number: null Hours worked: 50 Salary: 1122.0 class Abstraction.CommissionEmployee First Name: null Last Name: null Social Security Number: null Commission Rate: 0.3 Salary: 6000.0
You have a problem with declaring variables multiple times. By declaring them in a super class, they also get declared in a subclass. When you declare the variables with the same name in a subclass, you can address the superclass' variable via super.variable. But I would recommend you to simply delete the variable declarations in your subclasses, that were already declared in the superclass.
However this is not the root of your problem. A similar issue occures if you override methods, in your case the subclass that prints correctly does not override the getters, which are used to read out the information stored in your variables. In the class that prints out correctly the getters are found in the superclass and hence the getters are addressing the superclass variables. In the other 2 classes the overridden getters are found, that are using the variables found in the subclasses. Since you set only the variables in the superclass, the subclass variables are always null and so is your result.
I would recommend you to delete the overriden getters and the variables in the subclasses. You don't need them.