Java Reference
In-Depth Information
The definition of a simple
Queue
class that is based on a linked list is given in Dis-
play 15.29. A short demonstration program is given in Display 15.30. We have not
made our queue a generic queue to keep the definition simple, but it would be routine
to replace the data type
String
with a type parameter.
Queue
A
queue
is a first-in/first-out data structure; that is, the data items are removed from the
queue in the same order that they were added to the queue.
Self-Test Exercise
18. Complete the definition of the method
addToBack
in Display 15.29.
Display 15.29
A
Queue
Class
(part 1 of 2)
1
public
class
Queue
2{
3
private
class
Node
4
{
5
private
String item;
6
private
Node link;
7
public
Node( )
8
{
9
item =
null
;
10
link =
null
;
11
}
12
public
Node(String newItem, Node linkValue)
13
{
14
item = newItem;
15
link = linkValue;
16
}
17
}
//End of Node inner class
18
private
Node front;
19
private
Node back;
20
public
Queue( )
21
{
22
front =
null
;
23
back =
null
;
24
}
(continued)