queue.java

排队论模拟,最近刚刚找到的

/*
**********************************************************************************************************************
	Wal-Mart Checkout Simulation
	By: Dustin Grimmeissen and Richard Anderson

	-> Queue Class

	This class is used to store customers in a queue for each checkout line after a customer's arrival has been taken
	off of the priority queue.
**********************************************************************************************************************
*/

public class Queue
{
	public Customer Head;
	public Customer Tail;
	private int Size;
	private double ServiceRate;

	// Base Constructor
	public Queue()
	{
		Size = 0;
		ServiceRate = 0.1677;
		Head = null;
		Tail = null;
	}

	// Overloaded Constructor which allows a service rate to be entered for the queue
	public Queue( double Rate )
	{
		ServiceRate = Rate;
		Size = 0;
		Head = null;
		Tail = null;
	}

	//----------------------------------------------------------------------------
	// enqueue - Insert customer at the end of the queue.
	//----------------------------------------------------------------------------
	public void enqueue( Customer newCustomer )
	{
		if (Size > 0)
			Tail.NextInLine = newCustomer;
		else
			Head = newCustomer;

		Tail = newCustomer;

		Size++;
	}

	//----------------------------------------------------------------------------
	// dequeue - Remove customer from front of queue and shift others forward.
	//----------------------------------------------------------------------------
	public Customer dequeue()
	{
		if (Size > 0)
		{
			Customer ReturnCustomer = Head;
			Head = Head.NextInLine;
			Size--;
			return ReturnCustomer;
		}
		else
		{
			Customer nullCustomer = new Customer(-1);
			return nullCustomer;
		}
	}

	public void setRate( double Rate )
	{
		ServiceRate = Rate;
	}

	public int getSize()
	{
		return Size;
	}

	public double getRate()
	{
		return ServiceRate;
	}
}