public class CircularArrayQueue
{

private int[] elements;

private int head;

private int tail;

//初始化队列

public CircularArrayQueue(int initialCapacity) {

   elements = new int[initialCapacity];
}

//进队列，按照队列先进先出原则，从队尾插入，e为插入的数值，队列满或操作失败抛异常IllegalStateException。

public boolean add(int e) throws IllegalStateException 
{
   boolean isFull = tail>head && (tail-head)%elements.length==0;
   boolean isReachMaxInt = tail > elements.length && tail==Integer.MAX_VALUE;
   boolean isAdded = false;
   if(! isFull )
   {
       elements[tail%elements.length]=e;
       if( isReachMaxInt )
       {
           tail = tail%elements.length;
           head = head%elements.length;
       }
       tail++;
       isAdded= true;
   }
   else
   {
       isAdded =false;
       throw new IllegalStateException();
   }
   return isAdded;
}

//出队列，按照队列的先进先出原则，对头先出，队列为空或操作失败抛异常NoSuchElementException。

public int remove() throws NoSuchElementException 
{

      boolean isEmpty = tail==head;
      int result=0;
      if(! isEmpty)
      {
          result=elements[head%elements.length];
          head++;
      }
      else
      {
          throw new NoSuchElementException();
      }
      return result;
}

//获取队列头数值,队列不变化

public int getQueueHeadElement() throws NoSuchElementException 
{
   int result = 0;

   if(tail>head)
   {
       result=elements[head%elements.length];
   }
   else
   {
       throw new NoSuchElementException();
   }
   return result;

}

//获取队列尾数值,队列不变化

public int getQueueTailElement() throws NoSuchElementException
{
    int result = 0;

    if(tail>head)
    {
        result=elements[tail%elements.length-1];
    }
    else
    {
        throw new NoSuchElementException();
    }
    return result;
}

//获取队列长度

public int size() 
{

   return tail-head;

}

//查找数值value在队列中是否存在，如果存在返回true，否则返回false。

public boolean search(int value) 
{

   boolean isExist= false;
   if(tail>head)
   {
       for(int index=head;index<tail;index++)
       {
           if(value==elements[index%elements.length])
           {
               isExist=true;
               break;
           }
       }
   }
   return isExist;
}
}