Java Reference
In-Depth Information
Similarly, the following Hourly class extends the Employee class using the
extends keyword.
public class Hourly extends Employee
{
public float hourlyRate; //Pay rate
public float hoursWorked; //Weekly hours worked
public float computePay()
{
System.out.println(“Computing hourly pay for “ + name);
float pay = 0.0F;
if(hoursWorked <= 40)
{
pay = hourlyRate * hoursWorked;
}
else //Need to compute overtime
{
pay = (hourlyRate * 40) +
(hourlyRate * (hoursWorked - 40) * 1.5F);
}
return pay;
}
}
A child class has access to the fields and methods in the parent class,
depending on the access specifier, which is discussed in Chapter 7, “Advanced
Java Language Concepts.” The computePay() method of the Salary class dis-
plays the name of the employee being paid, but there is no name field in the
salary class. The name field is in Employee, the parent of Salary. In this exam-
ple, because name is public, Salary has acces to it and can use it at any point in
the Salary class.
Notice that the Hourly class prints out the employee's name within its com-
putePay() method, using the name field inherited from the Employee class.
Instantiating Child Objects
Now that we have defined the Employee, Salary, and Hourly classes, let's look
at a program that instantiates and uses these classes. The following Inherit-
Demo program creates an Employee, Salary, and Hourly object. Study the pro-
gram carefully and try to determine its output.
public class InheritDemo
{
public static void main(String [] args)
{
System.out.println(“Instantiating an Employee”);
