1
package queue;
2
3
/** *//**
4
* This is queue interface
5
*
6
* @author
7
* @version 1.0
8
*/
9
public interface IQueue
10

{
11
/** *//**
12
* Method that will push the element specified by the parameter into the
13
* queue
14
*
15
* @param object, the element that will be push into the queue
16
*/
17
public void enQueue(Object object);
18
19
/** *//**
20
* Method that will return the first element in the queue and also pull the
21
* element out of the stack, if there is no element left, it will return
22
* null
23
*
24
* @return object, the last element in the queue
25
*/
26
public Object deQueue();
27
28
/** *//**
29
* Method that will check if the queue is empty, if it is empty,it will
30
* return true,else it will return false
31
*
32
* @return boolean that indicates if the queue is empty or not
33
*/
34
public boolean isEmpty();
35
}
36

2

3


4

5

6

7

8

9

10



11


12

13

14

15

16

17

18

19


20

21

22

23

24

25

26

27

28


29

30

31

32

33

34

35

36

1
package queue;
2
3
import list.*;
4
5
/** *//**
6
* This class is the implementation of IQueue interface
7
*
8
* @author
9
* @version 1.0
10
*/
11
public class Queue implements IQueue
12

{
13
/** *//**
14
* Attributes
15
*/
16
private DoublyLinkedList dll;
17
18
/** *//**
19
* Constructor
20
*/
21
public Queue()
22
{
23
this.dll = new DoublyLinkedList();
24
}
25
26
/**//*
27
* (non-Javadoc)
28
*
29
* @see queue.IQueue#enQueue(java.lang.Object)
30
*/
31
public void enQueue(Object object)
32
{
33
this.dll.add(object);
34
}
35
36
/**//*
37
* (non-Javadoc)
38
*
39
* @see queue.IQueue#deQueue()
40
*/
41
public Object deQueue()
42
{
43
if(this.dll.isEmpty())
44
{
45
return null;
46
}
47
else
48
{
49
Object object = this.dll.get(0);
50
this.dll.remove(0);
51
return object;
52
}
53
}
54
55
/**//*
56
* (non-Javadoc)
57
*
58
* @see queue.IQueue#isEmpty()
59
*/
60
public boolean isEmpty()
61
{
62
return dll.isEmpty();
63
}
64
}
65

2

3

4

5


6

7

8

9

10

11

12



13


14

15

16

17

18


19

20

21

22



23

24

25

26


27

28

29

30

31

32



33

34

35

36


37

38

39

40

41

42



43

44



45

46

47

48



49

50

51

52

53

54

55


56

57

58

59

60

61



62

63

64

65
