1: /**
2: A class that implements the ADT queue by using
3: a two-part circular chain of linked nodes.
4:
5: @author Frank M. Carrano
6: @author Timothy M. Henry
7: @version 5.0
8: */
9: public final class TwoPartCircularLinkedQueue<T> implements QueueInterface<T>
10: {
11: private Node queueNode; // References first node in queue
12: private Node freeNode; // References node after back of queue
13:
14: public TwoPartCircularLinkedQueue()
15: {
16: freeNode = new Node(null, null);
17: freeNode.setNextNode(freeNode);
18: queueNode = freeNode;
19: } // end default constructor
21: // < Implementations of the queue operations go here. >
22: // . . .
24: private class Node
25: {
26: private T data; // Queue entry
27: private Node next; // Link to next node
28:
29: private Node(T dataPortion)
30: {
31: data = dataPortion;
32: next = null;
33: } // end constructor
34:
35: private Node(T dataPortion, Node linkPortion)
36: {
37: data = dataPortion;
38: next = linkPortion;
39: } // end constructor
40:
41: private T getData()
42: {
43: return data;
44: } // end getData
45:
46: private void setData(T newData)
47: {
48: data = newData;
49: } // end setData
50:
51: private Node getNextNode()
52: {
53: return next;
54: } // end getNextNode
55:
56: private void setNextNode(Node nextNode)
57: {
58: next = nextNode;
59: } // end setNextNode
60: } // end Node
61: } // end TwoPartCircularLinkedQueue