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Thread: problem with data access when a class call another class

  1. #1
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    Unhappy problem with data access when a class call another class

    Hello everybody,
    I am new to java and I can not finish this exercise.
    I have a timer (Prog1) that calls an Employee Report (Prog2).
    For every tick of the timer (Prog1), how can I double the value of the field basic_salary (Prog2)????
    Any help/advice/hints to this would be valuable to me becuase I dont know how to fight it.
    Thanks. Michael



    PROGRAM1
    ----------------------------------------------------------------------------------------
    import java.awt.*;
    import java.awt.event.*;
    import java.util.*;
    import javax.swing.*;
    import javax.swing.Timer; 
    // to resolve conflict with java.util.Timer
     
     
    public class TimerTest
    { 
    public static void main(String[] args)
    { 
    ActionListener listener = new TimePrinter();
     
    // construct a timer that calls the listener
    // once every 10 seconds
    Timer t = new Timer(1000, listener);
    t.start();
    JOptionPane.showMessageDialog(null, "Quit program?");
    System.exit(0);
    }
    }
     
    class TimePrinter implements ActionListener
    { 
    public void actionPerformed(ActionEvent event)
    { 
    Date now = new Date();
    System.out.println("Title current: " + now);
    Toolkit.getDefaultToolkit().beep();
    EmployeeProject3.main(null);
    }
    }
    -----------------------------------------------------------------------------------------


    PROGRAM2
    ----------------------------------------------------------------------------------------
    import static java.lang.Math.*;
    public class EmployeeProject3
    {
    public static void main(String[] args)
    { 
    // construct a Manager object
    Executive A = new Executive("Executive", 300, 7, 3);
    Manager B = new Manager("Manager", 400, 7, 0);
    Employee[] staff = new Employee[7];
     
    // fill the staff array with Manager and Employee objects
    staff[0] = A;
    staff[1] = B;
    staff[2] = new Employee("Employee", 500, 7, 0);
    staff[3] = new Employee("Employee", 500, 7, 0);
    staff[4] = new Employee("Employee", 500, 7, 0);
    staff[5] = new Employee("Employee", 500, 7, 0);
    staff[6] = new Employee("Employee", 500, 7, 0); 
     
    // print out information about all Employee objects 
     
    for (Employee e : staff)
    { 
    System.out.println("Type: " + e.getName() + "\t Basic Salary|" + e.getBasic_Salary()
    + "\t Height|" + e.getHeight() + "\t Radius|" + e.getRadius()
    + "\t Bonus|" + e.getBonus()+"\t Total|" + e.getTotal()); 
    } 
    }
    }
     
    class Employee
    { 
    private String name;
    private double basic_salary, total, radius, height;
     
    public Employee(String n, double s, double r, double h)
    {
    name = n;
    basic_salary= s;
    radius = r;
    height = h;
    }
     
    public String getName()
    {
    return name;
    }
     
    public double getBasic_Salary()
    {
    return basic_salary;
    }
     
    public double getRadius()
    {
    return radius;
    }
     
    public double getHeight()
    {
    return height;
    }
     
    public double getBonus()
    {
    double bonus=2*PI*radius;
    return Math.floor(bonus);
    }
     
    public double getTotal()
    {
    total=basic_salary+this.getBonus();
    return total;
    }
    }
     
    class Manager extends Employee
    { 
    public Manager(String n, double s, double r, double h)
    {
    super(n, s, r, h);
    } 
     
    public double getBonus()
    {
    double bonus=PI*pow (getRadius(),2);
    return Math.floor(bonus);
    } 
    }
     
    class Executive extends Manager
    { 
    public Executive (String n, double s, double r, double h)
    { 
    super(n, s, r, h);
    } 
     
    public double getBonus()
    {
    double bonus=PI*pow (getRadius(),2)*getHeight();
    return Math.floor(bonus);
    } 
    }
    -----------------------------------------------------------------------------------------
    Last edited by helloworld922; April 4th, 2010 at 10:32 AM.


  2. #2
    Administrator copeg's Avatar
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    Default Re: problem with data access when a class call another class

    basic_salary is an instance variable, and therefor you need an instance to double it. If you are looking to double all the instances of Employee in EmployeeProject3, then you need a reference to that for you actionPerformed to access it. You can do so by creating the instance as part of you TimerTest class or TimerPrinter class, and access it from there.

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