Polymorphism and the payroll program

[teddarr]

I have a program that uses Employee as the superclass. It has subclasses of SalariedEmployee, CommissionEmployee, BasePlusCommissionEmployee, and HoulyEmployee. This program works great to provide such data as first name, last name, SSN, and the salary information required. I have modified the program to include date of birth by adding a Date class. The birthdate is added to the output by the Employee superclass toString() method.

My problem: I need to modify the program to give each employee a $100 bonus during the month of their birthday. I have tried doing this in both the Employee class and the main method of the Test class.

My Questions: Which class would be most appropriate for this? (I think it needs to be in the Employee class?) Currently I am trying to do this in the Test class in conjuction with an array I have set up to polymorphically (which I don't fully understand yet) process the data. I get an error message that reads "currentMonth variable cannot be referenced from a static context"

Here's the main() method of the Test class and the toString() method of the Employee class. Can someone tell me what I'm doing wrong?

[HTML]public class PayrollSystemTest
{
final private int currentMonth = 3;

public static void main( String args[] )
{
// create subclass objects
SalariedEmployee salariedEmployee =
new SalariedEmployee( "John", "Smith", "111-11-1111", 3, 23, 1968, 800.00);
HourlyEmployee hourlyEmployee =
new HourlyEmployee( "Karen", "Price", "222-22-2222", 3, 12, 1957, 16.75, 40 );
CommissionEmployee commissionEmployee =
new CommissionEmployee(
"Sue", "Jones", "333-33-3333", 4, 1, 1996, 10000, .06 );
BasePlusCommissionEmployee basePlusCommissionEmployee =
new BasePlusCommissionEmployee(
"Bob", "Lewis", "444-44-4444", 10, 16, 1979, 5000, .04, 300 );

// create four-element Employee array
Employee employees[] = new Employee[ 4 ];

// initialize array with Employees
employees[ 0 ] = salariedEmployee;
employees[ 1 ] = hourlyEmployee;
employees[ 2 ] = commissionEmployee;
employees[ 3 ] = basePlusCommissionEmployee;

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

// generically process each element in array employees
for ( Employee currentEmployee : employees )
{
System.out.println( currentEmployee ); // invokes toString

// determine whether element is a BasePlusCommissionEmployee
if ( currentEmployee instanceof BasePlusCommissionEmployee )
{
// downcast Employee reference to
// BasePlusCommissionEmployee reference
BasePlusCommissionEmployee employee =
( BasePlusCommissionEmployee ) currentEmployee;

double oldBaseSalary = employee.getBaseSalary();
employee.setBaseSalary( 1.10 * oldBaseSalary );
System.out.printf(
"new base salary with 10%% increase is: $%,.2f\n",
employee.getBaseSalary() );

} // end if
//the problem is with this if statement. If it is commented out and only the body
//of the else statement is left, the program works, but without the bonus feature.
if (currentMonth == currentEmployee.getMon())
{
System.out.println("Birthday bonus this month: $100.00");
System.out.println("New amount + bonus earned: " + currentEmployee.earnings() + 100);
}
else
{

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

} // end for

// get type name of each object in employees array
for ( int j = 0; j < employees.length; j++ )
System.out.printf( "Employee %d is a %s\n", j,
employees[ j ].getClass().getName() );
} // end main
} // end class PayrollSystemTest[/HTML]

Employee class toString() method:
[HTML] public String toString()
{
return String.format( "%s %s\nsocial security number: %s\nbirthday: %s",
getFirstName(), getLastName(), getSocialSecurityNumber(), getDate() );
} // end method toString[/HTML]

[r035198x]

I have a program that uses Employee as the superclass. It has subclasses of SalariedEmployee, CommissionEmployee, BasePlusCommissionEmployee, and HoulyEmployee. This program works great to provide such data as first name, last name, SSN, and the salary information required. I have modified the program to include date of birth by adding a Date class. The birthdate is added to the output by the Employee superclass toString() method.

My problem: I need to modify the program to give each employee a $100 bonus during the month of their birthday. I have tried doing this in both the Employee class and the main method of the Test class.

My Questions: Which class would be most appropriate for this? (I think it needs to be in the Employee class?) Currently I am trying to do this in the Test class in conjuction with an array I have set up to polymorphically (which I don't fully understand yet) process the data. I get an error message that reads "currentMonth variable cannot be referenced from a static context"

Here's the main() method of the Test class and the toString() method of the Employee class. Can someone tell me what I'm doing wrong?

[HTML]public class PayrollSystemTest
{
final private int currentMonth = 3;

public static void main( String args[] )
{
// create subclass objects
SalariedEmployee salariedEmployee =
new SalariedEmployee( "John", "Smith", "111-11-1111", 3, 23, 1968, 800.00);
HourlyEmployee hourlyEmployee =
new HourlyEmployee( "Karen", "Price", "222-22-2222", 3, 12, 1957, 16.75, 40 );
CommissionEmployee commissionEmployee =
new CommissionEmployee(
"Sue", "Jones", "333-33-3333", 4, 1, 1996, 10000, .06 );
BasePlusCommissionEmployee basePlusCommissionEmployee =
new BasePlusCommissionEmployee(
"Bob", "Lewis", "444-44-4444", 10, 16, 1979, 5000, .04, 300 );

// create four-element Employee array
Employee employees[] = new Employee[ 4 ];

// initialize array with Employees
employees[ 0 ] = salariedEmployee;
employees[ 1 ] = hourlyEmployee;
employees[ 2 ] = commissionEmployee;
employees[ 3 ] = basePlusCommissionEmployee;

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

// generically process each element in array employees
for ( Employee currentEmployee : employees )
{
System.out.println( currentEmployee ); // invokes toString

// determine whether element is a BasePlusCommissionEmployee
if ( currentEmployee instanceof BasePlusCommissionEmployee )
{
// downcast Employee reference to
// BasePlusCommissionEmployee reference
BasePlusCommissionEmployee employee =
( BasePlusCommissionEmployee ) currentEmployee;

double oldBaseSalary = employee.getBaseSalary();
employee.setBaseSalary( 1.10 * oldBaseSalary );
System.out.printf(
"new base salary with 10%% increase is: $%,.2f\n",
employee.getBaseSalary() );

} // end if
//the problem is with this if statement. If it is commented out and only the body
//of the else statement is left, the program works, but without the bonus feature.
if (currentMonth == currentEmployee.getMon())
{
System.out.println("Birthday bonus this month: $100.00");
System.out.println("New amount + bonus earned: " + currentEmployee.earnings() + 100);
}
else
{

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

} // end for

// get type name of each object in employees array
for ( int j = 0; j < employees.length; j++ )
System.out.printf( "Employee %d is a %s\n", j,
employees[ j ].getClass().getName() );
} // end main
} // end class PayrollSystemTest[/HTML]

Employee class toString() method:
[HTML] public String toString()
{
return String.format( "%s %s\nsocial security number: %s\nbirthday: %s",
getFirstName(), getLastName(), getSocialSecurityNumber(), getDate() );
} // end method toString[/HTML]

Add the bonus logic to the method that calculates the salary every month.

[teddarr]

That's part of the problem. Each different category has the earnings calculated in the respective subclass. The bonus is to be added in either the super class (Employee) or the test class (PayrollTest) and using the Date class.

[r035198x]

That's part of the problem. Each different category has the earnings calculated in the respective subclass. The bonus is to be added in either the super class (Employee) or the test class (PayrollTest) and using the Date class.

Add it to the Superclass then.

[teddarr]

This is what I am trying to do. When I do I get the error or one similar to the one I listed in my first post. I don't know how to call a specific instance of the date class to pull only the month from it. I have tried using 'this', I have tried several different things and nothing seems to work for me. Could you please be more specific. I know I need to do add the logic to the Employee class.....but what?

I have the body of an if statement written, I need the if statement itself. I apparently don't have the knowledge I need to write it right now....but that is not from lack of trying.

[r035198x]

This is what I am trying to do. When I do I get the error or one similar to the one I listed in my first post. I don't know how to call a specific instance of the date class to pull only the month from it. I have tried using 'this', I have tried several different things and nothing seems to work for me. Could you please be more specific. I know I need to do add the logic to the Employee class.....but what?

I have the body of an if statement written, I need the if statement itself. I apparently don't have the knowledge I need to write it right now....but that is not from lack of trying.

In the calculate salary method, get the Employee's DOB, wrap it in a regorianCalendar, and get the month o birth using the get method of the gc class, then create another gc with today's date and extract the month in a similar manner. The rest is now straightforward.

[teddarr]

I have the program to the point where the Date class gives a number corresponding to the month. We are allowed to use a declared constant (for simplicity sake) for the current month. So.....

I am to the point where I need an if statement that compares the constant int currentMonth with the getMonth method of each instance of the different subclasses.

This is where my error comes in. I really think I am having trouble getting you to understand the problem. It would be a lot easier if I could post all of the code. BUT ist of all, it's against the rules, and 2nd, it would be really burdensome to post all of the different classes on the site.

The calculate salary method is in a sunclass that we are not supposed to modify for this calculation as we are supposed to make the changes once in either the Employee class or the test class. Not 4 times (once each in the subclasses). That defeats the purpose of the exercise.

Can you think of any key information I could be leaving out? Please let me know so I can post it. As it is, so far I have already considered all of your suggestions and they do not fit the problem.

[r035198x]

I have the program to the point where the Date class gives a number corresponding to the month. We are allowed to use a declared constant (for simplicity sake) for the current month. So.....

I am to the point where I need an if statement that compares the constant int currentMonth with the getMonth method of each instance of the different subclasses.

This is where my error comes in. I really think I am having trouble getting you to understand the problem. It would be a lot easier if I could post all of the code. BUT ist of all, it's against the rules, and 2nd, it would be really burdensome to post all of the different classes on the site.

The calculate salary method is in a sunclass that we are not supposed to modify for this calculation as we are supposed to make the changes once in either the Employee class or the test class. Not 4 times (once each in the subclasses). That defeats the purpose of the exercise.

Can you think of any key information I could be leaving out? Please let me know so I can post it. As it is, so far I have already considered all of your suggestions and they do not fit the problem.

Have a think about this and see if wont work for you


Inside the Employee class (Base class), you put a method called calculateBirthDayBonus

//The parameter month is the month for which the payroll is running

 public double calculateBirthDayBonus (int month) { 
     int birthMonth = ///  
     if(month == birthMonth) {
         return theBonus;
      }
      else {
         return 0.0;
      }
}
 
 

In each of the subclasses all you need to do is to adjust the calculate salary method like this

 public doulble calculateSalary() { 
     double bonus = calculateBirthDayBonus(thisMonth);
     //continue to get normal salary and then add the bonus at the end
}
 

[teddarr]

I'll give that a try. That's one approach I haven't tried yet. I think it may work.

It always gets me how simple some solutions are and why our brains block out the easy answers.

Thanks.