Java Reference
In-Depth Information
Display 13.3
An Abstract Class Implementing an Interface
★
1
public abstract class
MyAbstractClass
implements
Ordered
2{
3
private int
number;
4
private char
grade;
5
6
public boolean
precedes(Object other)
7
{
8
if
(other ==
null
)
9
return false
;
10
else if
(!(other
instanceof
HourlyEmployee))
11
return false
;
12
else
13
{
14
MyAbstractClass otherOfMyAbstractClass =
15
(MyAbstractClass)other;
16
return
(
this
.number < otherOfMyAbstractClass.number);
17
}
18
}
19
public abstract boolean
follows(Object other);
20
}
Display 13.4
Extending an Interface
1
public interface
ShowablyOrdered
extends
Ordered
2{
3
/**
4
Outputs an object of the class that precedes the calling object.
5
*/
6
public void
showOneWhoPrecedes();
7}
Neither the compiler nor the run-time system will
do anything to ensure that this comment is
satisfied.
A (concrete) class that implements the
ShowablyOrdered
interface must have a
definition for the method
showOneWhoPrecedes
and also have definitions for the
methods
precedes
and
follows
given in the
Ordered
interface.
