Queue.java

// This class implements the Queue
public class Queue<V> implements QueueInterface<V>{

 //TODO Complete the Queue implementation
 private NodeBase<V>[] queue;
 private int capacity, currentSize, front, rear;

	@SuppressWarnings("unchecked")
 public Queue(int capacity) {
 queue=new NodeBase[capacity];
 front=rear=-1;
 currentSize=0;
 this.capacity=capacity;
 }

 public int size() {
 return currentSize;
 }

 public boolean isEmpty() {
 return currentSize<=0;
 }
	
 public boolean isFull() {
 return currentSize>=capacity;
 }

 public void enqueue(Node<V> node) {
 if (isFull())
 return;

 if(front==-1) 
 front=0;
 rear=(rear+1)%capacity;
 queue[rear]=node;
 currentSize++; 
 }

 public NodeBase<V> dequeue() {
 if (isEmpty())
 return null;
 
 NodeBase<V> R = queue[front];
 if (front==rear)
 front=rear=-1;
 else
 front=(front+1)%capacity;
 currentSize--;
 return R;
 }

}