Re: Absract class and its sub clases

From:

Lew <lew@nospam.lewscanon.com>

Newsgroups:

comp.lang.java.help

Date:

Sun, 25 Mar 2007 10:28:01 -0400

Message-ID:

<bZudnWj2GetvG5vbnZ2dnUVZ_rLinZ2d@comcast.com>

teshmee@gmail.com wrote:

public abstract class Worker

{
protected String name;
protected double salaryRate;

double is a terrible type to model monetary facts.

You probably should make these instance variables private.

     public String getName()
    { ... }
    public double getsalaryRate()
    { ... }
    public void setName(String n)
    { ... }
    public void setsalaryRate(double sal)
    { ... }

    public abstract double weeklySalary();
}

public class ParttimeWorker extends Worker

Why does ParttimeWorker extend Worker? It makes no use of any parent class
behaviors or characteristics.

{
private double SalaryRate;

In accordance with Sun's nearly universally-followed coding conventions,
instance and method variable names should start with a lower-case letter.

     char Type;
    int NormalHours;
    int ExtraHours;

Why did you make these instance variables package-private?

    private double Salary;

    public ParttimeWorker(String SalaryRate,char Type,int NormalHours,int
ExtraHours);
    {
        this.SalaryRate = SalaryRate;
        this.Type = Type;
        this.NormalHours = NormalHours;
        this.ExtraHours = ExtraHours;
    }

    public double getSalaryRate()
    {
        return SalaryRate;
    }

    public char getType()
    {
        return Type;
    }

    public int getNormalHours()
    {
        return NormalHours;
    }

    public int getExtraHours()
    {
        return ExtraHours;
    }

    public void setSalaryRate(double s)
    {
        SalaryRate = s;
    }

    public void setType(char t)
    {
        Type = t;
    }

    public void setNormalHours(int n)
    {
        NormalHours = n;
    }

    public void setExtraHours(int e)
    {
        ExtraHours = e;
    }

    public void calculate()
    {
        if (this.NormalHours > 40)
        this.Salary = (this.ExtraHours * 1.5) + (this.NormalHours *
this.SalaryRate);

It is good practice to enclose the body of control statements (if, while, ...)
in braces ('{' and '}').

         else
        this.Salary = this.NormalHour * this.SalaryRate;
    }

}

You didn't implement weeklySalary() in the subclass, but that begs the
question of why the subclass inherits from Worker in the first place.

I will bet you that if you look at the compiler error (You did get a compiler
error, right? You completely neglected to report what the error was.) that it
will tell you /precisely/ what you did wrong. It did, didn't it?

-- Lew