calling to superclass/constructors questions.

[hayden06f4i]

hey guys, im doing a lesson on Polymorphism, and i have a basic question, not really regarding polymorphism, but the basic of a constructor question.

i have an entire group of java programs,
Employee.java (abstract) then 4 classes
commissionemployee.java
salariedemployee.java
hourlyemployee.java
basepluscommission.java
that all extend Employee. the program functions, shows the name, ssn, salary and i need to add functionality to also show the birthdate. i have added in the employee class here:

public abstract class Employee 
{
   private String firstName;
   private String lastName;
   private String socialSecurityNumber;
   private String birthDate;

   // six-argument constructor
   public Employee( String first, String last, String ssn,
   		int month, int day, int year )
   {
      firstName = first;
      lastName = last;
      socialSecurityNumber = ssn;
      birthDate = new Date ( month, day, year);
   } // end six-argument Employee constructor

i haven't worked with "Date" before, do i declare it like i did ok? and in one of the subclasses, how do i set up the constructor, here are 2 different ways, not sure which is right, or if either is:

im guessing this:

public class CommissionEmployee extends Employee 
{
   private double grossSales; // gross weekly sales
   private double commissionRate; // commission percentage

   // six-argument constructor
   public CommissionEmployee( String first, String last, String ssn, [COLOR="Red"]String birthDate[/COLOR], 
      double sales, double rate, )
   {
      super( first, last, ssn, [COLOR="Red"]birthDate[/COLOR] );
      setGrossSales( sales );
      setCommissionRate( rate );
      
   } // end six-argument CommissionEmployee constructor

and not this:

public class CommissionEmployee extends Employee 
{
   private double grossSales; // gross weekly sales
   private double commissionRate; // commission percentage

   // six-argument constructor
   public CommissionEmployee( String first, String last, String ssn,[COLOR="Red"] int month, int day, int year[/COLOR], 
      double sales, double rate, )
   {
      super( first, last, ssn, [COLOR="Red"]month, day, year[/COLOR] );
      setGrossSales( sales );
      setCommissionRate( rate );
      
   } // end six-argument CommissionEmployee constructor

[hayden06f4i]

or should it actually say "private Date birthdate;" when i declare variables?

[hayden06f4i]

im not sure how or where, but i will also need some sort of method for date like getMonth, getDay, getYear, right?

[Tolls]

birthDate should be a Date.
I'd create a constructor that takes a Date object.

As for the getters, you just want a getBirthDate, which returns the Date. You don't want to be worrying about display stuff in here.

Depending on how you are creating these objects will determine how you get that Date (or how you display it), but that should not be something your model is concerned with.

[hayden06f4i]

there is so much code, i can't really post it all here, but there is a PayrollTest.java application that i need to modify as well, that contains the main method for everything.

so it should be declared like this:

private Date birthDate;

and not:

private String birthDate;

?

[Tolls]

Well, a birthDate sounds like a Date to me.
There's no "should be", though, since there may be a very good reason to declare it as a String. I just can't think of one straight away.

[hayden06f4i]

so after debugging countless errors, im trying to figure out what im missing so far here:

// Fig. 10.4: Employee.java
// Employee abstract superclass.

public abstract class Employee 
{
   private String firstName;
   private String lastName;
   private String socialSecurityNumber;
   private Date birthDate;

   // six-argument constructor
   public Employee( String first, String last, String ssn,
   		int month, int day, int year )
   {
      firstName = first;
      lastName = last;
      socialSecurityNumber = ssn;
      birthDate = new Date ( month, day, year);
   } // end six-argument Employee constructor

   // set first name
   public void setFirstName( String first )
   {
      firstName = first; // should validate
   } // end method setFirstName

   // return first name
   public String getFirstName()
   {
      return firstName;
   } // end method getFirstName

   // set last name
   public void setLastName( String last )
   {
      lastName = last; // should validate
   } // end method setLastName

   // return last name
   public String getLastName()
   {
      return lastName;
   } // end method getLastName

   // set social security number
   public void setSocialSecurityNumber( String ssn )
   {
      socialSecurityNumber = ssn; // should validate
   } // end method setSocialSecurityNumber

   // return social security number
   public String getSocialSecurityNumber()
   {
      return socialSecurityNumber;
   } // end method getSocialSecurityNumber
   
   // set birth date
   public void setBirthDate( int month, int day, int year )
   {
      birthDate = new Date( month, day, year );
   } // end method setBirthDate

   // return birth date
   public Date getBirthDate()
   {
      return birthDate;
   } // end method getBirthDate


   // return String representation of Employee object
   @Override
      public String toString()
   {
      return String.format( "%s %s\n%s: %s\n%s: %s", 
         getFirstName(), getLastName(), 
         "social security number", getSocialSecurityNumber(), 
         "birth date", getBirthDate() );
   } // end method toString


   // abstract method overridden by concrete subclasses
   public abstract double earnings(); // no implementation here
} // end abstract class Employee

im getting these errors:

c:\SimplyJava\PayrollSystem10.8>javac *.java
Employee.java:9: cannot find symbol
symbol  : class Date
location: class Employee
   private Date birthDate;
           ^
Employee.java:64: cannot find symbol
symbol  : class Date
location: class Employee
   public Date getBirthDate()
          ^
Employee.java:18: cannot find symbol
symbol  : class Date
location: class Employee
      birthDate = new Date ( month, day, year);
                      ^
Employee.java:60: cannot find symbol
symbol  : class Date
location: class Employee
      birthDate = new Date( month, day, year );
                      ^
4 errors

how exactly do i use "Date"? do i have to import it?

[Tolls]

Yes, you have to import it.
The API is also quite handy.

I did suggest passing a Date object into the constructor as well.

[hayden06f4i]

i added this code into my Employee.java file, which im assuming is the equivalent to importing, only more legwork?

public class Date 
{
   private int month; // 1-12
   private int day; // 1-31 based on month
   private int year; // any year

   // constructor: call checkMonth to confirm proper value for month; 
   // call checkDay to confirm proper value for day
   public Date( int theMonth, int theDay, int theYear )
   {
      month = checkMonth( theMonth ); // validate month
      year = theYear; // could validate year
      day = checkDay( theDay ); // validate day

   } // end Date constructor

   // utility method to confirm proper month value
   private int checkMonth( int testMonth )
   {
      if ( testMonth > 0 && testMonth <= 12 ) // validate month
         return testMonth;
      else // month is invalid 
      { 
         System.out.printf( 
            "Invalid month (%d) set to 1.", testMonth );
         return 1; // maintain object in consistent state
      } // end else
   } // end method checkMonth

   // utility method to confirm proper day value based on month and year
   private int checkDay( int testDay )
   {
      int[] daysPerMonth = 
         { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
   
      // check if day in range for month
      if ( testDay > 0 && testDay <= daysPerMonth[ month ] )
         return testDay;
   
      // check for leap year
      if ( month == 2 && testDay == 29 && ( year % 400 == 0 || 
           ( year % 4 == 0 && year % 100 != 0 ) ) )
         return testDay;
   
      System.out.printf( "Invalid day (%d) set to 1.", testDay );
      return 1;  // maintain object in consistent state
   } // end method checkDay
   
   // return a String of the form month/day/year
   public String toString()
   { 
      return String.format( "%d/%d/%d", month, day, year ); 
   } // end method toString
} // end class Date

otherwise, for cleaner/clearer/reduced code, i can just import it using?

import java.util.*;????

[Tolls]

Use the proper Date class.
One of the major things about programming in general is not reinventing the wheel.

And import the class itself, not '*'.
So:

import java.util.Date;

[hayden06f4i]

Yes, you have to import it.
The API is also quite handy.

I did suggest passing a Date object into the constructor as well.

Use the proper Date class.
One of the major things about programming in general is not reinventing the wheel.

And import the class itself, not '*'.
So:

import java.util.Date;

in going back to the book and REreading the instructions it says to use CLASS Date of fig8.7 (study from 2 chapters ago) and that is what i put in there for code, which shows the date as requested in a format like this:

6/22/1982

when i did the "import" instead i get this:

Sun Jun 22 00:00:00 EDT 1919

so there is still that question, i have one more to add to the mix after i get this settled ;)

[hei1233212000]

Did you put the Date.class and the Employee.class in the same directory?

[Tolls]

OK.
You didn't say that.
And you didn't do that in your code either.

So create that Date class and use that.

[hayden06f4i]

second question:

ok to the hierarchy of this program is this:

Employee.java (superclass)

and 4 subclasses that all inherit from Employee.

and 1 "test" program that has the main method.

i have the first portion done, now i need it, so it ask the user to "enter current month" 1 -12, and if the month entered is one of the employees birthday then they get a $100 bonus. so here is what im thinking

i need the if statement in the PayrollTest main method right?

the if statement should be something like reading the line the user enters converting it from string to int? and comparing that to the int month in the employees birthday?

if ( currentMonth = currentEmployee.getMonth() )
{

System.out.printf(
"earned $%,.2f\n\n", currentEmployee.earnings() "plus earned $100 bonus."
}

am i on the right track?

[hayden06f4i]

OK.
You didn't say that.
And you didn't do that in your code either.

So create that Date class and use that.

sorry it didn't strike me until i returned to reread it.....i evidently misunderstood that part in my first 75 times reading the instructions...;)

[hayden06f4i]

MORE DETAILS:

here is my current cmd line output: (in black, what in red i need to add)

c:\SimplyJava\PayrollSystem10.8>javac *.java

c:\SimplyJava\PayrollSystem10.8>java PayrollSystemTest
Date object constructor for date 12/25/1968
Date object constructor for date 11/10/1982
Date object constructor for date 9/4/1980
Date object constructor for date 6/22/1982
Employees processed individually:

salaried employee: John Smith
social security number: 111-11-1111
birth date: 12/25/1968
weekly salary: $800.00
earned: $800.00

hourly employee: Karen Price
social security number: 222-22-2222
birth date: 11/10/1982
hourly wage: $16.75; hours worked: 40.00
earned: $670.00

commission employee: Sue Jones
social security number: 333-33-3333
birth date: 9/4/1980
gross sales: $10,000.00; commission rate: 0.06
earned: $600.00

base-salaried commission employee: Bob Lewis
social security number: 444-44-4444
birth date: 6/22/1982
gross sales: $5,000.00; commission rate: 0.04; base salary: $300.00
earned: $500.00

[COLOR="Red"]Enter Current Month (1-12)[/COLOR]

Employees processed polymorphically:

salaried employee: John Smith
social security number: 111-11-1111
birth date: 12/25/1968
weekly salary: $800.00
earned $800.00 [COLOR="Red"]plus $100 birthday bonus[/COLOR]

hourly employee: Karen Price
social security number: 222-22-2222
birth date: 11/10/1982
hourly wage: $16.75; hours worked: 40.00
earned $670.00

commission employee: Sue Jones
social security number: 333-33-3333
birth date: 9/4/1980
gross sales: $10,000.00; commission rate: 0.06
earned $600.00

base-salaried commission employee: Bob Lewis
social security number: 444-44-4444
birth date: 6/22/1982
gross sales: $5,000.00; commission rate: 0.04; base salary: $300.00
new base salary with 10% increase is: $330.00
earned $530.00

Employee 0 is a SalariedEmployee
Employee 1 is a HourlyEmployee
Employee 2 is a CommissionEmployee
Employee 3 is a BasePlusCommissionEmployee

c:\SimplyJava\PayrollSystem10.8>

[Tolls]

second question:

ok to the hierarchy of this program is this:

Employee.java (superclass)

and 4 subclasses that all inherit from Employee.

and 1 "test" program that has the main method.

i have the first portion done, now i need it, so it ask the user to "enter current month" 1 -12, and if the month entered is one of the employees birthday then they get a $100 bonus. so here is what im thinking

i need the if statement in the PayrollTest main method right?

the if statement should be something like reading the line the user enters converting it from string to int? and comparing that to the int month in the employees birthday?

if ( currentMonth = currentEmployee.getMonth() )
{

System.out.printf(
"earned $%,.2f\n\n", currentEmployee.earnings() "plus earned $100 bonus."
}

am i on the right track?

Pretty much, though I would do this in its own method rather than trying to squeeze this logic into main(). Then call it from main() (or wherever).

[hayden06f4i]

does you statement hold true even after seeing my output post above?

[hayden06f4i]

Pretty much, though I would do this in its own method rather than trying to squeeze this logic into main(). Then call it from main() (or wherever).

first for simplicity sake let me try to put it in main() so that i have the reasoning correct, here is my code (red portions are modifications that are what im working on)

// Fig. 10.9: PayrollSystemTest.java
// Employee hierarchy test program.
[COLOR="Red"]import java.util.Scanner; //program uses Scanner[/COLOR]

public class PayrollSystemTest 
{
   public static void main( String[] args ) 
   {
      // create subclass objects
      SalariedEmployee salariedEmployee = 
         new SalariedEmployee( "John", "Smith", "111-11-1111", 12,25,1968, 800.00 );
      HourlyEmployee hourlyEmployee = 
         new HourlyEmployee( "Karen", "Price", "222-22-2222", 11,10,1982, 16.75, 40 );
      CommissionEmployee commissionEmployee = 
         new CommissionEmployee( 
         "Sue", "Jones", "333-33-3333", 9,4,1980, 10000, .06 );
      BasePlusCommissionEmployee basePlusCommissionEmployee = 
         new BasePlusCommissionEmployee( 
         "Bob", "Lewis", "444-44-4444", 6,22,1982, 5000, .04, 300 );

      System.out.println( "Employees processed individually:\n" );
      
      System.out.printf( "%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() );

      // 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;
      
      [COLOR="Red"]System.out.println ( "Enter the current month ( 1 -12 ):" );
      
      // create scanner to obtain input from user
		Scanner input = new Scanner ( System.in );
	
	  int currentMonth; // current month input by user
	  
	  currentMonth = input.nextInt ();
	  
	  if ( currentMonth == employees.getMonth() )
	  {[/COLOR]
      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;

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

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

         System.out.printf( 
            "earned $%,.2f\n\n", currentEmployee.earnings() );
         [COLOR="Red"]System.out.print ( "plus a $100 birthday Bonus." );[/COLOR]
      } // 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() ); 
      [COLOR="Red"]} //end if[/COLOR]
      
     [COLOR="Red"] else if ( currentMonth != employees.getMonth() )
	  {[/COLOR]
      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;

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

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

         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() ); 
      [COLOR="Red"]} //end if[/COLOR]
   } // end main
} // end class PayrollSystemTest

[hayden06f4i]

what id like to do it get the reasoning down, and get it functional, then understand how to make it more streamlined after if possible.

as currently constituted i get 2 errors, on each IF line cannot find symbol regarding the "month"

i have tried using employees.month and employees.getMonth()