Message can be "Input array is null" or "Input array does not have sufficient space available"

ArrayQueue Code:

import exceptions.EmptyCollectionException;

public class ArrayQueue implements QueueADT {

private T queueArray[]; // Array holding queue private static final int DEFAULT_SIZE = 5; private int front; // position of element at the front of the queue private int rear; // First free position at rear of the queue private int size; // number of elements in the queue

@SuppressWarnings("unchecked") public ArrayQueue(int initialSize) { front = -1; rear = 0; queueArray = (T[]) new Object[initialSize]; }

public ArrayQueue() { this(DEFAULT_SIZE); }

@Override public void enqueue(T element) { // TODO Auto-generated method stub if (isFull()) { growQueue(); }

if (isEmpty()) { front = (front + 1) % queueArray.length; }

queueArray[rear] = element; rear = (rear + 1) % queueArray.length; size++;

}

@SuppressWarnings("unchecked") private void growQueue() { Object[] temp = new Object[queueArray.length + DEFAULT_SIZE]; int index = front; for (int i = 0; i

} queueArray = (T[]) temp; } private boolean contains(T element) {

int index = front;

for (int c = 0; c

return false;

}

private int indexOf(T element) {

int index = front;

for (int c = 0; c

return -1;

}

@Override public T dequeue() { // TODO Auto-generated method stub if (isEmpty()) { throw new EmptyCollectionException("array queue"); } T retElement = queueArray[front]; queueArray[front] = null; front = (front + 1) % queueArray.length; size--; return retElement; }

@Override public T first() { // TODO Auto-generated method stub if (isEmpty()) { throw new EmptyCollectionException("array queue"); } return queueArray[front]; }

@Override public boolean isEmpty() { // TODO Auto-generated method stub return (size == 0); }

private boolean isFull() { return (size == queueArray.length); }

@Override public int size() { // TODO Auto-generated method stub return size; }

public String toString() { String retString = "["; int index = front;

for (int c = 0; c

retString += "]"; return retString; }

}

QueueADT Code:

public interface QueueADT {

public void enqueue(T element); public T dequeue(); public T first(); public boolean isEmpty(); public int size(); }

QueueTesterCode:

public class QueueTester {

public static void main(String[] args) { //test both queues

//LinkedQueue lq = new LinkedQueue(); ArrayQueue lq = new ArrayQueue(); System.out.println("Queue: " + lq); lq.enqueue(4); System.out.println("First: " + lq.first()); lq.enqueue(5); System.out.println("First: " + lq.first()); lq.enqueue(6); lq.enqueue(7); System.out.println("Queue: " + lq);

System.out.println("Dequeue [4]: " + lq.dequeue()); System.out.println("First [5]: " + lq.first()); System.out.println("Queue [5 6 7]: " + lq); System.out.println("Dequeue [5]: " + lq.dequeue()); System.out.println("First [6]: " + lq.first()); System.out.println("Queue [6 7]: " + lq); lq.enqueue(8); lq.enqueue(9); System.out.println("Queue [6 7 8 9]: " + lq);

}

}

+ toArray(T[] anArray) : void - Returns an array containing all of the elements in this queue in proper sequence (from front to rear element). This method may throw the following exceptions: a. NullPointerException- if the array is null (use the java NullPointerException) b. ArrayCapacityException - if the size of the array is not sufficient to store the elements of the queue (create this exception) + toArray(T[] anArray) : void - Returns an array containing all of the elements in this queue in proper sequence (from front to rear element). This method may throw the following exceptions: a. NullPointerException- if the array is null (use the java NullPointerException) b. ArrayCapacityException - if the size of the array is not sufficient to store the elements of the queue (create this exception)