Implementing an ArrayQueue in java

Problem:

Write a program that implements an ArrayQueue in java.

Output:

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Solution:

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01	public class ArrayQueue<E> implements Queue<E> {

02	private E[] elements;

03	private int front;

04	private int back;

05	private static final int INITIAL_CAPACITY = 4;

06

07	public ArrayQueue() {

08	elements = (E[]) new Object[INITIAL_CAPACITY];

09

}

10

11	public ArrayQueue(int capacity) {

12	elements = (E[]) new Object[capacity];

13

}

14

15	public void add(E element) {

16	if (size() == elements.length - 1) {

17

resize();

18

}

19	elements[back] = element;

20	if (back < elements.length - 1) {

21

++back;

22

} else {

23	back = 0; //wrap

24

}

25

}

26

27	public E element() {

28	if (size() == 0) {

29	throw new java.util.NoSuchElementException();

30

}

31	return elements[front];

32

}

33

34	public boolean isEmpty() {

35	return (size() == 0);

36

}

37

38	public E remove() {

39	if (size() == 0) {

40	throw new java.util.NoSuchElementException();

41

}

42	E element = elements[front];

43	elements[front] = null;

44

++front;

45	if (front == back) { // queue is empty

46	front = back = 0;

47

}