Cycle queue

This is a practice for cycle queue. Cycle queue uses array to store elements. Main character of cycle queue is that it allocate space for one time. When deQueue and enQueue, it saves time for space allocation compared to normal queue. Disadvantage is that the lenght is constant once it initializes.

1. package jan;
2. public class CycleQueue {
3.     private int[] queue;
4.     private final int len;
5.     private int rear;
6.     private int front;
7.     CycleQueue(int len) {
8.         this.len = len + 1;
9.         queue = new int[this.len];
10.         rear = front = 0;
11.     }
12.     int deQueue() {
13.         if (front == rear) {
14.             throw new RuntimeException(“queue is empyt now.”);
15.         }
16.         int result = queue[front];
17.         front = (front + 1) % len;
18.         return result;
19.     }
20.     void enQueue(int value) {
21.         if ((rear + 1) % len == front) {
22.             throw new RuntimeException(“queue is full now.”);
23.         }
24.         queue[rear] = value;
25.         rear = (rear + 1) % len;
26.     }
27.     void print() {
28.         for (int i = front; i != rear; i = (i + 1) % len) {
29.             System.out.print(queue[i] + “\t”);
30.         }
31.         System.out.println();
32.     }
33.     public static void main(String[] args) {
34.         CycleQueue queue = new CycleQueue(3);
35.         queue.enQueue(1);
36.         queue.enQueue(2);
37.         queue.enQueue(3);
38.         System.out.println(queue.deQueue());
39.         queue.enQueue(4);
40.         System.out.println(queue.deQueue());
41.         queue.enQueue(5);
42.         queue.print();
43.         System.out.println();
44.     }
45. }