QueueDArray.java

package com.ds;

import java.util.Arrays;

public class QueueDArray<T> {

	Object[] ArrayQueue;
	int Rear;
	int Front;
	int size;
		public QueueDArray(int size) {
		this.size=size;
		ArrayQueue= new Object[this.size];
		Front=-1;
		Rear=-1;
		}

		public Boolean isFull(){
			return(Rear==size-1);
		}
		public Boolean isEmplty(){
			return(Front==-1|| Front>Rear);
		}
		public void Queue(Object newItem){
			 ensureCapacity(Rear+2);
			Rear=Rear+1;
			ArrayQueue[Rear]= newItem;
			if(Front==-1)
				Front=0;
		}
		public void ensureCapacity( int minCapacity){
			int oldCapacity= getSize();
			if(minCapacity>oldCapacity){
				int newCapacity=oldCapacity*2;
				if(newCapacity<minCapacity)
					newCapacity=minCapacity;
				ArrayQueue=Arrays.copyOf(ArrayQueue, newCapacity);
			}
		}
		public int getSize(){
			return ArrayQueue.length;
		}
		public T DeQueue(){
			if(isEmplty()){
				System.out.println("queue is empty");
				return null;
			}
			T ObjectOut=(T) ArrayQueue[Front];
			Front=Front+1;
			return ObjectOut;
		}
}