barbershop.java

Barber Shop algorithm Synchronization Simulator

		notifyAll();
		customerOnSofa ++;
		customerStandCount --;
		customerSofaQ[sofaTop] = id;
		sofaTop =(sofaTop+1)%sofaSize;
		repaint();
		updateCustomerStatus(applet, id, 5);  //sitting on sofa
		notifyAll();
	}

	/* The customer will first wait for his/her turn, then an available barber chair.
	 * He/she will spend a random time on the chair before send the ready flag to the barber.
	 */
	public synchronized void sitBarberChair(BarberShopApplet applet, int id)
	{
		  while(customerSofaQ[sofaBottom] != id)
		  {
			  System.out.println("Customer " + id + "is waiting for the chair turn");
			  try{ wait(); } catch(InterruptedException e) { }
		  }

		  while(chairFull())
			{
				try	{	wait();	}catch(InterruptedException e) {}
			}
			customerSofaQ[sofaBottom] = 0;
			sofaBottom =(sofaBottom+1)%sofaSize;		//get up from sofa
			customerOnSofa --;
			customerOnChair ++;
			for(int i = 1; i <= chairSize; i++)
			{
				if(customerChairQ[i] == 0)
				{
					customerChairQ[i] = id;
					customerReady[i] = id;
					i = chairSize;			// get out of the loop
				}
			}
			updateCustomerStatus(applet,id, 6);
			repaint();

		  try{
				applet.c[id].sleep((int) (Math.random()*frameDelay));
			}catch(InterruptedException e) { }

			notifyAll();
	}


	 /* If there is a customer waiting and no cashier, a barber will be a cashier when he/she
	  * is not cutting hair.
	  */
	 public synchronized void getCashierLock(BarberShopApplet applet, int bid)
	 {
	    if((wantPayCount > 0) && (hasCashier!= 1))
	    {
	  	 	 hasCashier= 1;
	  	 	 cashierID = bid;
	  	 	 //updateBarberStatus(applet, bid, 9); // a cashier right now
	  	 	 repaint();
	  	 	 System.out.println("Barber " + bid + " got the cashier Lock right now");
	  	 	 notifyAll();
	    }

	 }

     public synchronized void performCashier(BarberShopApplet applet, int bid)
     {
		 while(wantPayCount > 0)
		 {
			 System.out.println("Barber " + bid + " is a cashier right now");
			 updateBarberStatus(applet, bid, 2);
			 try{ wait(); } catch(InterruptedException e) {}
		}
		 cashierID = 0;
		 hasCashier= 0;
		 notifyAll();
	 }

	 /* The customer will wait for a cashier first, then wait for his/her turn to pay.
	  * It will take random time to get the receipt, the customer then will leave the shop.
	  */
     public synchronized void waitPay(BarberShopApplet applet, int cid)
     {

		while(customerPayQ[payBottom] != cid)
		{
			 if((applet.requestFlag == 1) && (cid == 3))
			 	repaintFlag = 1;
			 try{ wait(); } catch(InterruptedException e) { }
		}

		if(applet.requestFlag == 1)		// for 1st process in unfair situation
		{
			while(true)
			{
				try{ applet.c[cid].sleep((int) (Math.random()*frameDelay)); }
				catch(InterruptedException e) { }
			}
		}

		while(hasCashier!= 1)
		{
			 try{ wait(); } catch(InterruptedException e) { }
		}
		try{ applet.c[cid].sleep((int) (Math.random()*frameDelay)); }
		catch(InterruptedException e) {}
		updateCustomerStatus(applet, cid, 9);
		payBottom++;
		wantPayCount --;
		exitID = cid;
		exitArray[exitTop] = cid;
		exitTop ++;
		customerCount --;
		repaint();
		notifyAll();
	 }

     public synchronized void updateCustomerStatus(BarberShopApplet applet, int cid, int status)
     {
		 applet.c[cid].status = status;
		 applet.mc.println(status, "c", cid);
	 }

	 public synchronized void updateBarberStatus(BarberShopApplet applet, int bid, int  status)
	 {
		 applet.b[bid].status = status;
		 applet.mc.println(status, "b", bid);
	 }


	 public void clear()
	 {
		 size 				= 4;    							//default buffer size
		 customerCount 		= 0;
		 payTop 	= payBottom 	= 1;
		 chairTop 	= chairBottom 	= 0;
		 sofaTop 	= sofaBottom 	= 0;
		 customerTop= customerBottom= 1;
		 outTop 	= outBottom 	= 0;
		 finishedCustomerQ 	= new int[11];
		 customerOut		= new int[2];
		 customerOnSofa 	= 0;			//the count of customers on the sofa
		 customerOnChair 	= 0;		//the count of customers on the barber chairs
		 customerStandCount = 0;		//the count of customers standing
		 wantPayCount 		= 0;			//the count of customers waiting for paying
		 hasCashier			= 0;
		 cashierID 			= 0;					//the barber ID for who is performing as a cashier
		 exitID 			= 0;
		 exitTop			= 0;
		 repaintFlag 		= 0;
	 }

	/*
	 * Draw the barber shop on the canvas
	 */
	public void paint(Graphics g){
		g.setFont(new Font("TimesRoman", Font.BOLD, 12));
		g.setColor(Color.blue);
		int xpos = 120;
		int ypos = 10;
		g.setFont(new Font("TimesRoman", Font.BOLD, 18));
		/************************************/
		/* Draw Barber Chairs on the canvas */
		/************************************/
		g.drawString("Barber Chairs", xpos+150, ypos+5);
		for(int i = 1; i <= chairSize; i++)
		{
			g.draw3DRect(xpos+100+70*(i-1), ypos+20, 28, 28, true);
			if(i != cashierID)	g.drawString("B"+i, xpos+103+70*(i-1), ypos+70);
		}

		g.setColor(Color.red);
		for(int j=1;  j <= chairSize; j ++)
		{
			if(customerChairQ[j] != 0)
			{
				g.drawString(Integer.toString(customerChairQ[j]), xpos + 105 + 70*(j-1), ypos+35);
				g.draw3DRect(xpos+100+70*(j-1), ypos+20, 28, 28, true);
			}
		}

		/**********************************/
		/* Draw Cashier's waiting queue */
		/*********************************/
		g.setColor(Color.blue);
		g.drawString("Cashier", xpos+410, ypos+45);
		g.setFont(new Font("TimesRoman", Font.BOLD, 14));
		if(cashierID != 0)
		{
			g.drawString("B "+cashierID, xpos+430, ypos+20);
		}
		g.draw3DRect(xpos+410, ypos+60, 60, 20, true);
		g.setFont(new Font("TimesRoman", Font.BOLD, 12));
		int b = payBottom;
		System.out.println("wantPaycount is " + wantPayCount);
		if(repaintFlag == 1)
		{
			for(int i = 0; i < 3; i++)
			{
				if(customerPayQ[i+b] != 0)
				g.drawString("C"+customerPayQ[i+b], xpos+430, ypos+100);
				ypos += 20;
			}
		}

		else
		{
			for(int i = 0; i < wantPayCount; i++)
			{
				if(customerPayQ[i+b] != 0)
				g.drawString("C"+customerPayQ[i+b], xpos+430, ypos+100);
				ypos += 20;
			}
		}

		/**********************************/
		/* Draw standing room on canvas   */
		/**********************************/
		g.setFont(new Font("TimesRoman", Font.BOLD, 12));
		ypos = 10;
		g.drawString("Standing Room Area", xpos-100, ypos+160);
		b = customerBottom;
		for(int i = 0; i < customerStandCount; i++)
		{
			g.drawString("C"+(i+b), xpos+80-25*i, ypos+120);
		}

		g.setColor(Color.green);
		g.drawString("Entrance", xpos-110, ypos+100);
		g.drawString("--------->", xpos-110, ypos+105);
		g.setColor(Color.red);
		System.out.println("outTop is: " + outTop);
		for(int i = outBottom; i <= outTop; i++)
		{
			if(customerOut[i] > 0)
			g.drawString("C "+customerOut[i], xpos-80, ypos+80-20*i);
		}
		g.setColor(Color.red);
		g.drawString("Exit", xpos+530, ypos+10);
		for(int i = 0; i < exitTop; i++)
		{
			if(exitArray[i] != 0)
			g.drawString("C" + exitArray[i], xpos+530, ypos+25+15*i);
		}

		/**********************************/
		/* Draw waiting Sofa on canvas   */
		/**********************************/
		xpos = 100;
		ypos = 10;
		g.setColor(Color.blue);
		g.drawString("Sofa", xpos+225, ypos+185);

		for(int i = 0; i < sofaSize; i++)
		{
			g.draw3DRect(xpos+180+28*(i), ypos+140, 28, 28, true);
		}


		g.setColor(Color.red);
		int k = sofaBottom;
		for(int j=0; j < customerOnSofa; j++)
		{
				g.drawString(Integer.toString(customerSofaQ[k]), xpos + (190+28*3) -28*(j), ypos+155);
				g.draw3DRect(xpos+180+28*3 - 28*(j), ypos+140, 28, 28, true);
				k = (k+1)%sofaSize;

		}

	}
}