gui.java

Reader Writer Problem to solve synchronization issues

import java.awt.*;
import java.lang.*;

public class Gui extends Canvas
{
   private Image[] RWimg;
   private Image Currentimg;
   private int Currentpos[][]= new int[5][2];
   private int tn,xpos,ypos,prevxpos,prevypos,scale=10;
   private int rcval=0,writeval=1;
   private String r[]={"R1>","R2>","R3>"};
   private String move[]={"HF","VF","HL","VL"};

   private int init[][]={{5,5},{65,5},{35,40},{425,35},{460,35}};
   private int mutexdb[][]={{5,160},{65,160},{35,160},{415,170},{415,210}};
   private int mutexright[][]={{200,175},{200,210},{200,245}};
   private int datapos[][]={{185,5},{250,5},{315,5},{425,5},{460,5}};
   private int dbasepos[][]={{220,82},{260,82},{300,82},{260,82},{260,82}};

   private int mutexbottom[]={35,247};
   private int dbbottom[]={375,247};
   private int dbtop[]={375,140};
   private int dbleft[]={335,190};

   private int db[]={370,180};
   private int mutex[]={25,200};
   private int readval[]={0,0,0,0,0};
   private int dbase[]={150,35};
   private int rcpos[]={dbase[0]-40,dbase[1]+40};
   private int dbsize[]={250,95};

   private int writebox[]={dbase[0]+105,dbase[1]+20};

   private boolean blinkerflag=false;

   private Image mutexlock, mutexunlock;
   private Image dblock, dbunlock;
   private Image Current_mutexlock,Current_dblock;
   private Image textbox; 


 public Gui(Image[] img,Image[] other)
 {
    Panel p=new Panel();
    p.setLayout(new BorderLayout());
    RWimg=img;

	mutexunlock= other[0];
	mutexlock=other[1]; 
	dbunlock=other[2];
	dblock=other[3]; 
	textbox=other[4];

	Current_mutexlock=mutexunlock;
	Current_dblock=dbunlock;

    Currentimg=RWimg[0];
     for(int i=0;i<5;i++)
	{ 
		Currentpos[i][0]=init[i][0];
		Currentpos[i][1]=init[i][1];
	}
 }
public void reset()
{
    Current_mutexlock=mutexunlock;
    Current_dblock=dbunlock;
	blinkerflag=false;

   for(int i=0; i<4;i++) readval[i]=0;
    rcval=0;writeval=1;
 
    Currentimg=RWimg[0];
     for(int i=0;i<5;i++)
        {
                Currentpos[i][0]=init[i][0];
                Currentpos[i][1]=init[i][1];
        }
	repaint();
}
 public void paint(Graphics g)
 {
   int n=RWimg.length; 

   for (int i=0;i<n;i++)
   	g.drawImage(RWimg[i],Currentpos[i][0],Currentpos[i][1],this);

   g.drawImage(Current_mutexlock,mutex[0],mutex[1],this);

   g.drawImage(Current_dblock,db[0],db[1],this);

   g.setColor(getBackground());
   g.draw3DRect(dbase[0],dbase[1],dbsize[0],dbsize[1],false);
   g.setColor(getForeground());

   g.setFont(new Font("Helvetica",Font.BOLD,14));
   g.drawString("Database",dbase[0]+100,dbase[1]+15);

    g.drawImage(textbox,writebox[0],writebox[1],this);
    g.drawString(String.valueOf(writeval),writebox[0]+15,writebox[1]+18);

    g.setFont(new Font("Helvetica",Font.BOLD,12));
    g.drawImage(textbox,rcpos[0],rcpos[1],this);
    g.drawString("RC",rcpos[0]+12,rcpos[1]-3);
    g.setFont(new Font("Helvetica",Font.BOLD,14));
    g.drawString(String.valueOf(rcval),rcpos[0]+15,rcpos[1]+18);

    g.setFont(new Font("Helvetica",Font.BOLD,12));
    g.drawString("MUTEX",mutex[0]+5,mutex[1]+42);

    g.setFont(new Font("Helvetica",Font.BOLD,12));
    g.drawString("DB",db[0]+6,db[1]+60);

    for (int i=0; i<n; i++){

 	if((i==0)||(i==3))
        g.setColor(Color.red);
        else if((i==2)||(i==4))
        g.setColor(Color.blue);
        else
        g.setColor(Color.green);

	if(i<3){
    		g.setFont(new Font("Helvetica",Font.BOLD,12));
	 	g.drawString(r[i],datapos[i][0]-25,datapos[i][1]+15);
	}

        g.drawImage(textbox,datapos[i][0],datapos[i][1],this);
    	g.setFont(new Font("Helvetica",Font.BOLD,14));
        g.drawString(String.valueOf(readval[i]),
				datapos[i][0]+15,datapos[i][1]+18);
    }

   g.drawLine(0,290,499,290);
	
 }

synchronized void object_move (int x11,int y11,int x14,int y14,String str)
 
{
        int x1=x11,x2,x3,x4=x14;
	int y1=y11,y2,y3,y4=y14;
	int x_value,y_value;

        String mov=str;
 
 
        Graphics g=getGraphics();
        g.clearRect(Currentpos[tn][0],Currentpos[tn][1],
                     Currentimg.getWidth(this),Currentimg.getHeight(this));
        g.dispose();
 
 
            this.prevxpos=x1;
            this.prevypos=y1;
 
         if(mov.equals("VF")){
         //Vertical First
            x2 = x1;
            x3 = x4;
            y2 = (y1 + y4) / 2;
            y3 = y2; }
 
         else if (mov.equals("HL")){
         //Horizontal First
	   x3=x14;
           x2=x3;
           y2=y1;
           y3=y14;}

         else if(mov.equals("VL")){
         //vertical L first
           x2=x1;
	   y3=y14;
           y2=y3;
           x3=x14; }
 
         else 
	 {
            x2 = (x1+x4)/2;
            x3 = x2;
            y2 = y1;
            y3 = y4; 
	  }


 

/*======================================*/

        if ((x1==x2) && (y1<y2))
        {
            this.xpos = x1;
            this.ypos = y1;
            top_to_bottom(y1,y2);
        }
        else if ((x1==x2) && (y1>y2))
        {
            this.xpos = x1;
            this.ypos = y1;
            bottom_to_top(y1,y2);
        }
 
        else if ((x1<x2) && (y1 == y2))
        {
            this.xpos = x1;
            this.ypos=y1;
            left_to_right (x1,x2);
        }
        else if((x1>x2) && (y1 == y2))
        {
            this.xpos = x1;
            this.ypos=y1;
            right_to_left(x1 ,x2);
        }
 

/*======================================*/

        if ((x2==x3) && (y2<y3))
        {
            this.xpos = x2;
            this.ypos = y2;
            top_to_bottom (y2, y3);
        }
 
        else if  ((x2==x3) && (y2>y3))
        {
            this.xpos = x2;
            this.ypos = y2;
            bottom_to_top (y2, y3);
        }
 
        else if ((x2<x3) && (y2==y3))
        {
            this.xpos = x2;
            this.ypos = y2;
            left_to_right (x2, x3);
        }
 
        else if((x2>x3) && (y2 == y3))
        {
            this.xpos = x2;
            this.ypos = y2;
            right_to_left (x2 ,x3);
        }
 

/*======================================*/

        if ((x3==x4) && (y3<y4))
        {
         this.xpos = x3;
         this.ypos = y3;
         top_to_bottom(y3,y4);
        }
        else if ((x3==x4) && (y3>y4))
        {
            this.xpos = x3;
            this.ypos = y3;
            bottom_to_top(y3,y4);
        }
 
        else if ((x3<x4) && (y3 == y4))
        {
            this.xpos = x3;
            this.ypos = y3;
            left_to_right (x3,x4);
        }
        else if((x3>x4) && (y3 == y4))
        {
            this.xpos = x3;
            this.ypos = y3;
            right_to_left(x3 ,x4);
        }
    }
 
/*======================================*/

    void top_to_bottom (int start, int end){
        for(int i = start; i <=end; i+= 10)
        {this.prevypos = this.ypos;
         this.ypos = i;
        pos_to_paint();}
        this.prevypos=this.ypos;
        this.ypos=end;
        pos_to_paint();
    }
 
 
    void bottom_to_top (int start, int end){
        for(int i = start; i >=end; i-= 10)
        {this.prevypos = this.ypos;
         this.ypos = i;
        pos_to_paint();}
        this.prevypos=this.ypos;
        this.ypos=end;
        pos_to_paint();
    }
 
 
    void left_to_right (int start, int end){
        for(int i = start; i <=end; i+= 10)
        {this.prevxpos = this.xpos;
         this.xpos = i;
        pos_to_paint();}
        this.prevxpos=this.xpos;
        this.xpos=end;
        pos_to_paint();
    }
 
 
    void right_to_left (int start, int end){
        for(int i = start; i >=end; i-= 10)
        {this.prevxpos = this.xpos;
        this.xpos = i;
        pos_to_paint();}
        this.prevxpos=this.xpos;
        this.xpos=end;
        pos_to_paint();
    }
 
    void pos_to_paint(){
        guipaint();
        pause (550 - (50*scale));
    }





    void pause (int time){

        try{Thread.sleep(time);}
        catch(InterruptedException e) {}
    }


    public void guipaint() {
	Graphics g=getGraphics();
	g.clearRect(prevxpos,prevypos,
		Currentimg.getWidth(this),Currentimg.getHeight(this));
	Currentpos[tn][0]=xpos;
	Currentpos[tn][1]=ypos;
        g.drawImage(Currentimg,xpos, ypos, this);
	
   	g.setColor(getBackground());
   	g.draw3DRect(dbase[0],dbase[1],dbsize[0],dbsize[1],false);
   	g.setColor(getForeground());

	this.prevxpos=this.xpos;
	this.prevypos=this.ypos;
	g.dispose();
    }