Java Reference
In-Depth Information
Display 7.5
The Derived Class
SalariedEmployee
(part 2 of 2)
39
/**
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Returns the pay for the month.
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*/
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public
double
getPay()
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{
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return
salary/12;
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}
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/**
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Precondition: newSalary is nonnegative.
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*/
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public
void
setSalary(
double
newSalary)
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{
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if
(newSalary >= 0)
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salary = newSalary;
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else
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{
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System.out.println("Fatal Error: Negative salary.");
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System.exit(0);
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}
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}
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public
String toString()
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{
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return
(getName() + " " + getHireDate().toString()
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+ "\n$" + salary + " per year");
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}
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public
boolean
equals(SalariedEmployee other)
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{
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return
(getName().equals(other.getName())
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&& getHireDate().equals(other.getHireDate())
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&& salary == other.salary);
We will show you a better way to
define
equals
later in this
chapter.
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}
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}
Parent and Child Classes
A base class is often called the
parent class
. A derived class is then called a
child class
. This
analogy is often carried one step further. A class that is a parent of a parent of a parent of
another class (or some other number of “parent of” iterations) is often called an
ancestor
class
. If class A is an ancestor of class B, then class B is often called a
descendent
of class A.
parent class
child class
ancestor class
descendent
class
