// This class uses a queue to store groups of permutations of the numbers 1 - 7.

import java.util.Random;

public class GrabBag
{
	private int[] bag_queue;
	private int beg, end, count;
	
	public GrabBag()
	{
		bag_queue = new int[14];
		beg = end = count = 0;
		
		// Load up fourteen numbers
		enqueueSeven();
		enqueueSeven();
	}
	
	// Get the next number in the bag. 
	public int getNext()
	{
		return dequeue();
	}
	
	// Add one number to the end of the queue
	private void enqueue(int i)
	{
		bag_queue[end] = i;
		end = (end+1)%14;
		count++;
	}
	
	// Get one number from the beginning of the queue
	private int dequeue()
	{
		int retval = bag_queue[beg];
		beg = (beg+1)%14;
		count--;
		
		// If the bag has less than seven numbers left, get seven more
		if (count < 7)
			enqueueSeven();
		
		return retval;
	}
	
	// Method to permute the numbers 1 - 7 and enqueue them.
	private void enqueueSeven()
	{
		Random rand = new Random();
		int[] numbers = new int[7];
		int n;
		
		for (int i = 0; i < 7; i++)
		{
			n = rand.nextInt(7) + 1;
			
			numbers[i] = n;
			
			// Make sure our new number isn't already in the array,
			// and correct if it is.
			for (int j = 0; j < i; j++)
			{
				if (numbers[j] == n)
				{
					n = (n%7)+1;
					j = -1;
				}
				else
					numbers[i] = n;
			}
		}
		
		for (int i = 0; i < 7; i++)
			enqueue(numbers[i]);
	}
}