package Queue; public class QueueArray implements Queue{ private static final int CAP=7;//队列默认大小 private Object[] elements; private int capacity; private int front; private int rear; public QueueArray (int cap) { this.capacity=cap+1; this.elements=new Object[this.capacity]; this.front=0; this.rear=0; } @Override public int getSize() { // TODO Auto-generated method stub return (rear-front+capacity)%capacity; } @Override public boolean isEmpty() { // TODO Auto-generated method stub return front==rear; } @Override public void enqueue(Object e) { // TODO Auto-generated method stub if(getSize()==capacity-1) expandSpace(); elements[rear]=e; rear=(rear+1)%capacity; } private void expandSpace() { // TODO Auto-generated method stub Object[] a=new Object[elements.length*2]; int i=front; int j=0; while(i!=rear) { a[j++]=elements[i]; i=(i+1)%capacity; } elements=a; capacity=elements.length; front=0; rear=j; } @Override public Object dequeue() throws QueueEmptyException { // TODO Auto-generated method stub if(isEmpty()) throw new QueueEmptyException("错误，空队列"); Object obj=elements[front]; elements[front]=null; front=(front+1)%capacity; return obj; } @Override public Object peek() throws QueueEmptyException { // TODO Auto-generated method stub if(isEmpty()) throw new QueueEmptyException("错误，空队列"); return elements[front]; } }