Question

1. Suppose you were given the job to write a Java class to manage employee payroll information in an HR management system. Each employee will be modeled as a single EmployeePayroll object (much like the Student objects discussed in class). The state of the EmployeePayroll object includes the first name and last name of the employee, a unique 15 digit employee number for each employee, a number of hours that they've worked this week (which could be a fraction of an hour), and the wages per hour the employee earns (measured in dollars and cents). Hours worked and wages per hour are never allowed to fall below zero, and the class should enforce this behavior.

   The behavior of the EmployeePayroll object is that any of the above member variables can be accessed (so accessor methods need to be written for them). First name, last name and Employee ID can only be set in a constructor method - there should be no mutators given for these fields, and a special constructor should be written to set these values on initialization. The wages per hour field should have a mutator method (but keep in mind that wages cannot be allowed to be set to less than $0.0). In addition to the above, the class should provide three different ways to change the number of hours worked - on that merely sets the hours as a mutator, one that adds to the hours already in place for the employee, and one that resets the employee's hours to zero. Given the above capabilities of the employee payroll record and the skeleton below, write a Java class that can store an employee payroll record.

   public class EmployeePayroll {
     // private variables go here
   
     public EmployeePayroll( /* Parameters go here*/ ) {
       // Fill in the constructor.  Default for hours and wages is 0 
     }
   
     // write accessors as described above
   
     // write mutators as described above
   
     public void incrementHours(/*Parameters go here*/) {
       // Fill in the method.  This method should take a number of hours worked
       // as an argument and increment the total hours by that amount.
     }
   
     public void resetPayCycle(/* Parameters go here*/) {
       // Fill in the method.  This method should reset the variables to start a new week
     }
   }
   
   

2. Override the methods toString() and equals() inherited from Object for this EmployeePayroll class. The toString() method should return the employee's name, ID, and current calculated pay (wages * hours) as a String. The equals() method should return true if two EmployeePayroll objects have the same employee ids, regardless of name, wages or hours.
3. Write a short test program that tests the EmployeePayroll class you implemented above. Your short program should create a few new EmployeePayroll objects and test a variety of conditions, including a number that your class should not allow (such as setting a negative hourly wage).

Answer 1

Here is the completed code for this problem including Test program. Make sure you paste both files separately. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

//EmployeePayroll.java

public class EmployeePayroll {

    // private variables go

    private String firstName;

    private String lastName;

    private String employeeID; // better to make this String than int

    private double hoursWorked;

    private double wagePerHour;

    // constructor taking first,last names and employee id

    public EmployeePayroll(String first, String last, String id) {

         firstName = first;

         lastName = last;

         employeeID = id;

         // using 0 for hours and wage

         hoursWorked = 0;

         wagePerHour = 0;

    }

    // accessors as described

    public String getFirstName() {

         return firstName;

    }

    public String getLastName() {

         return lastName;

    }

    public String getEmployeeID() {

         return employeeID;

    }

    public double getHoursWorked() {

         return hoursWorked;

    }

    public double getWagePerHour() {

         return wagePerHour;

    }

    // mutators as described

    public void setHoursWorked(double hoursWorked) {

         // changing hours only if parameter is positive

         if (hoursWorked >= 0)

             this.hoursWorked = hoursWorked;

    }

    public void setWagePerHour(double wagePerHour) {

         // changing wage only if parameter is positive

         if (wagePerHour >= 0)

             this.wagePerHour = wagePerHour;

    }

    // adds some specific hours to hours worked

    public void incrementHours(double hoursWorked) {

         // changing hours only if parameter is positive

         if (hoursWorked > 0) {

             // adding parameter hoursWorked to instance variable hoursWorked

             this.hoursWorked += hoursWorked;

         }

    }

    public void resetPayCycle() {

         // clearing hours worked

         hoursWorked = 0;

    }

    // returns the pay for current pay cycle

    public double calculatePay() {

         return hoursWorked * wagePerHour;

    }

    @Override

    public String toString() {

         // returning a String containing full name, id and pay formatted to 2

         // digits after decimal

         return String.format("Name: %s, ID: %s, Pay: $%.2f", firstName + " "

                 + lastName, employeeID, calculatePay());

    }

    @Override

    public boolean equals(Object ob) {

         //assuming ob is an EmployeePayroll

         EmployeePayroll emp = (EmployeePayroll) ob;

         //returning true if both employees have same id

         return this.employeeID.equals(emp.employeeID);

    }

}

//Test.java (tester program)

public class Test {

    public static void main(String[] args) {

         //creating two EmployeePayroll objects

         EmployeePayroll emp1 = new EmployeePayroll("Oliver", "Queen",

                 "123456789112345");

         EmployeePayroll emp2 = new EmployeePayroll("Felicity", "Smoak",

                 "333453489112995");

        

         //setting 10 as hours worked, 25 as wages per hour for emp1

         emp1.setHoursWorked(10);

         emp1.setWagePerHour(25);

        

         //setting 42 as hours worked, 20 as wages per hour for emp2

         emp2.setHoursWorked(42);

         emp2.setWagePerHour(20);

        

         //displaying both employees details

         System.out.println("emp1: " + emp1);

         System.out.println("emp2: " + emp2);

        

         //displaying hours worked for emp1

         System.out.println("emp1 hours worked: " + emp1.getHoursWorked());

         //trying to change to -2 (should not be effective)

         emp1.setHoursWorked(-2);

         //displaying hours worked for emp1

         System.out.println("emp1 hours worked: " + emp1.getHoursWorked());

        

         //adding 10 hours to hours worked for emp1

         emp1.incrementHours(10);

         //displaying hours worked for emp1

         System.out.println("emp1 hours worked: " + emp1.getHoursWorked());

        

         //clearing hours worked and displaying

         emp1.resetPayCycle();

         System.out.println("emp1 hours worked: " + emp1.getHoursWorked());

        

         //similarly testing setWagePerHour on emp2

         System.out.println("emp2 wage per hour: " + emp2.getWagePerHour());

         emp2.setWagePerHour(-24);

         System.out.println("emp2 wage per hour: " + emp2.getWagePerHour());

            

         //testing equals method

         System.out.println("emp1 == emp2: "+emp1.equals(emp2));

         System.out.println("emp1 == emp1: "+emp1.equals(emp1));

        

    }

}

/*OUTPUT*/

emp1: Name: Oliver Queen, ID: 123456789112345, Pay: $250.00

emp2: Name: Felicity Smoak, ID: 333453489112995, Pay: $840.00

emp1 hours worked: 10.0

emp1 hours worked: 10.0

emp1 hours worked: 20.0

emp1 hours worked: 0.0

emp2 wage per hour: 20.0

emp2 wage per hour: 20.0

emp1 == emp2: false

emp1 == emp1: true