import java.util.*;public class CircularArrayQueueTest{   public static void main(String[] args)   {      Queue<String> q = new CircularArrayQueue<String>(5);      q.add("Amy");      q.add("Bob");      q.add("Carl");      q.add("Deedee");      q.add("Emile");      q.remove();      q.add("Fifi");      q.remove();      for (String s : q) System.out.println(s);   }}/**     A first-in, first-out bounded collection. */ class CircularArrayQueue<E> extends AbstractQueue<E>{    /**        Constructs an empty queue.        @param capacity the maximum capacity of the queue    */    public CircularArrayQueue(int capacity)    {       elements = (E[]) new Object[capacity];       count = 0;       head = 0;       tail = 0;    }    public boolean offer(E newElement)    {       assert newElement != null;      if (count < elements.length)       {         elements[tail] = newElement;          tail = (tail + 1) % elements.length;          count++;         modcount++;         return true;      }      else          return false;   }    public E poll()    {       if (count == 0) return null;      E r = elements[head];       head = (head + 1) % elements.length;       count--;       modcount++;      return r;    }    public E peek()    {       if (count == 0) return null;      return elements[head];    }    public int size()    {       return count;    }    public Iterator<E> iterator()   {      return new QueueIterator();            }   private class QueueIterator implements Iterator<E>   {      public QueueIterator()      {         modcountAtConstruction = modcount;      }      public E next()       {          if (!hasNext()) throw new NoSuchElementException();         E r = elements[(head + offset) % elements.length];          offset++;         return r;      }      public boolean hasNext()       {          if (modcount != modcountAtConstruction)             throw new ConcurrentModificationException();         return offset < elements.length;      }      public void remove()       {          throw new UnsupportedOperationException();       }      private int offset;      private int modcountAtConstruction;   }   private E[] elements;    private int head;    private int tail;    private int count;    private int modcount;}