csma.java

cdma－cd的java源代码cdma－cd的java源代码

      ;
    }
  }

  public void backoff(int count) {
    
    int slotTime = 200;

    myCounter = new Counter( 
      (int)((myRandom.nextDouble()*(double)Math.pow(2,count))*(double)slotTime) 
    );

    while(myCounter.getCount()>0) {
      sleep(50);
    }

  }

  public void update() {
    if (myState==BACKOFF) {
      myCounter.decrement();
    }
	  return;
  }

  public boolean send() {

    myState = CARRIER_SENSE;
    while(!myMedium.isFree(myPosition)) {
      sleep(100);
    }

    myState = TRANSMIT;
    if (myMedium.send(myId, myPosition, myNetwork.getFrameSize())==false) {
      myState = BACKOFF;
      return false;
    }
    else {
      myState = IDLE;
      return true;
    }
    
  }

  public void run() {

    while (true) {		
      if (mySendRequest==true) {
        mySendRequest=false;

        myBackoffCount = 0;
        while (send()==false) {
          backoff(myBackoffCount);
          myBackoffCount++;
        }
      }
      sleep(100);
    }
  } 

}

/* the network class which simulates the network */
class Network {

  public static final int NUM_STATIONS = 4;

  Medium myMedium;
  Station[] myStations;

  int	myFrameSize = 150; 
  int i=0;


  public Network() {
	/* initializes the medium and also indicates the number of stations */	
    myMedium = new Medium();
    myStations = new Station[NUM_STATIONS];

  }
  public void stop()
  {
  		for(int j=0;j<i;j++)
		  myStations[j].setState(0); //setting the state of stations to idle
		  
		  update();
	  }
	public void addStation(int x)
	{
		myStations[i] = new Station(i++,x, this, myMedium);
		
	}

 public void init() {

		i=0;
	/* the stations are initialized */
	
   // myStations[0] = new Station(0, 10, this, myMedium);
   
   // myStations[1] = new Station(1, 50, this, myMedium);
   // myStations[2] = new Station(2, 90, this, myMedium);
  }

  public int convertPositionToPixel(int position) {
    return (int)Math.round((double)(position*400)/(double)myMedium.getBusLength());    
  }


  public int getFrameSize() {
    return myFrameSize;
  }

  public void setFrameSize(int size) {
    myFrameSize = size; 
  }

  public void update() {

	int index;
	if(i>1)
     myMedium.update();
	
    for (index = 0; index</*NUM_STATIONS*/i; index++) {
		myStations[index].update();
	}
  }

  public void paint(Graphics g) {

    int index;
    int pixel;

    Integer busLength = new Integer(myMedium.getBusLength());
    Integer stationNumber;
    Integer backoffCount;
    Integer backoffRemain;

      //draw states
    g.setColor(Color.white);
  	 g.fillRect(120,350,20,20); 
	 g.setColor(Color.black);  
	 g.drawString("IDLE",150,360); 

    g.setColor(Color.green);
    g.fillRect(240,350,20,20);
     g.setColor(Color.black);  
    g.drawString("TRANSMIT",270,360); 

    g.setColor(Color.blue);	
	 g.fillRect(360,350,20,20);
	  g.setColor(Color.black);  
  g.drawString("CARRIER-SENSE",380,360); 
 

    g.setColor(Color.red);	
    g.fillRect(480,350,20,20); 
     g.setColor(Color.black);  
    g.drawString("BACK-OFF",510,360); 

 	
	  // draw bus
   
    g.setColor(Color.black);
    g.fillRect(100,200,400,10);
     
    g.drawString("0",90,225); 
    g.drawString(busLength.toString(),500,225); 
    g.drawLine(100,210,100,220);
    g.drawLine(498,210,498,220);

    // draw stations and indicate their states

    for (index = 0; index</*NUM_STATIONS*/i; index++) {
      pixel = convertPositionToPixel(myStations[index].getPosition());
      stationNumber = new Integer(index+1);
      switch (myStations[index].getState()) {
        case Station.IDLE:
          g.setColor(Color.white);
          break;
        case Station.CARRIER_SENSE:
          g.setColor(Color.blue);
          break;
        case Station.TRANSMIT:
          g.setColor(Color.green);
          break;
        case Station.BACKOFF:
          g.setColor(Color.red);
          break;
        default:
          g.setColor(Color.pink);
      }
      
     
      g.fillRect(88+pixel,230,25,25);
      g.setColor(Color.black);
      g.drawRect(88+pixel,230,25,25);
      g.drawString("Station "+stationNumber.toString(),85+pixel,270); 
      g.drawLine(100+pixel,200, 100+pixel,230);      
      g.drawString("Station "+stationNumber.toString(),50,30+index*40+15); 

      if (myStations[index].getState() == Station.BACKOFF) {
        backoffCount = new Integer(myStations[index].getBackoffCount());
        backoffRemain = new Integer(myStations[index].getBackoffRemain());

        g.drawString("k = " + backoffCount.toString(),90+pixel-3,300); 
        g.drawString("t = " + backoffRemain.toString(),90+pixel-3,320); 

      }

    }

    // draw frames
    
    int start, end, id;
    Signal[] signals = myMedium.getSignals();

    for ( index=0; index<myMedium.MAX_SIGNALS; index++ ) {
      if ( signals[index] != null ) {        

        id    = signals[index].getStationId();

        start = convertPositionToPixel(signals[index].getLeftPart().getStart());
        end   = convertPositionToPixel(signals[index].getLeftPart().getEnd());        
        if (signals[index].getLeftPart().getCollisionFlag() )
			{
          g.setColor(Color.red);
        
         }
        else
          g.setColor(Color.black);
          
        g.fillRect(100+start,(id+1)*40,Math.abs(end-start),8); 
		
        start = convertPositionToPixel(signals[index].getRightPart().getStart());
        end   = convertPositionToPixel(signals[index].getRightPart().getEnd());        
        if (signals[index].getRightPart().getCollisionFlag() )
         {
          g.setColor(Color.red);
          
			}
        else
          g.setColor(Color.black);
        g.fillRect(100+end,(id+1)*40,Math.abs(start-end),8); 

      }
    }
    


  }


  public boolean handleEvent(Event e) {

    if (e.id == Event.MOUSE_DOWN) {
		if(i==1)
		{
			Frame alarm = new alarmFrame("Please add another station..min 2 stations",400,410);
			alarm.show();
			System.out.println("Please add another station..min 2 stations");
		}
		else
		{
      int index;  
      int pixel;

      for (index = 0; index<NUM_STATIONS; index++) {
        pixel = convertPositionToPixel(myStations[index].getPosition());
        if ((e.x>=88+pixel)&&(e.x<=113+pixel)&&(e.y>=230)&&(e.y<=255)) {
         	 myStations[index].setSendRequest(true);          
         
			

          
          return true;
        }
      }
      
    }}

    return false;

  }


}


class alarmFrame extends Frame
{
	public alarmFrame(String msg,int x1,int y1)
	{
		setSize(170,140);
		setLocation(x1-200,y1-350);
		setLayout(new GridLayout(2,1));
		Label m = new Label(msg);
		Button ok = new Button("OK");
		add(m);
		add(ok);
		
		
	}
	
	public boolean action (Event ev1, Object arg)
	 {
		if (ev1.target instanceof Button) 
		{
			String label = (String)arg;

			if (label.equals("OK"))
			{
				setVisible(false);
			} 
		}
		return true;
	}
}	
/* the csma class */

public class csma extends Applet {

  private Image     myOffScreenImage = null;
  private Graphics  myOffScreenGraphics = null;
  private boolean   myResized = true;
  
  Network myNetwork;
  public static Timer myTimer;
  int clicked=0;
  Button mySetSizeButton;
  Button stopButton;
  Button addButton;
  Button clearButton;
  
  TextField mySizeTextField;
  TextField posTextField;
  int start;
  int posArray[] = new int[10];
  int count=0;
  
  public void init()
  {
    myNetwork = new Network();
    
    // the network is initialized
    myNetwork.init();
	
	// the clock is started	
	 myTimer = new Timer(myNetwork,this,50);
	 myTimer.start(); 

 
    setBackground(Color.yellow);
   
    mySetSizeButton = new Button("FrameSize:");
    stopButton = new Button("Stop");
    addButton = new Button("AddStation");
    clearButton = new Button("Clear");

    mySizeTextField = new TextField("150");
    posTextField = new TextField(3);
    
    setLayout (new BorderLayout());
	
	 Panel p = new Panel();
	 p.setLayout( new GridLayout(2,1));
	 	 
    Panel p1 = new Panel();

    p1.setLayout(new FlowLayout());
    p1.add(addButton);
    p1.add(posTextField);
    p.add(p1);
    
    Panel panel = new Panel();
    panel.setLayout(new FlowLayout());
    
		
	 panel.add(stopButton);	
	 panel.add(clearButton);
    panel.add(mySetSizeButton);
    panel.add(mySizeTextField);
	 p.add(panel);
	
    add ("South", p );
    setSize(600,470);
    

  }

  public void destroy() {
 }

  public void update( Graphics g ) {  

    if ( null == myOffScreenImage || myResized ) {
      myOffScreenImage = createImage( size().width,size().height );
      myOffScreenGraphics = myOffScreenImage.getGraphics();
      myResized = false;
    }

    myOffScreenGraphics.setColor( getBackground() );
    myOffScreenGraphics.fillRect( 0, 0, size().width,size().height );
    myOffScreenGraphics.setColor( g.getColor() );
    paint( myOffScreenGraphics );

    g.drawImage( myOffScreenImage, 0, 0, this );
  }

  public void paint( Graphics g ) {


    Integer time = new Integer(myTimer.myTime);

	  // draw time

    g.setColor(Color.black);
//    g.drawString("Time:   "+time.toString(),80,10); 
  
   
	  // draw network
	  myNetwork.paint(g); 
	     

  }

  public boolean handleEvent(Event e) {

    if ( myNetwork.handleEvent(e) ) {
      repaint();
      return true;
    }
    
    
    return super.handleEvent(e);

  }

	public boolean action (Event ev1, Object arg) {
		if (ev1.target instanceof Button) 
		{
			String label = (String)arg;

			if (label.equals("FrameSize:")) 
			{
	       myNetwork.setFrameSize(Integer.parseInt(mySizeTextField.getText()));       
				return true;
	      }
			if(label.equals("Stop"))
			{
				System.out.println("pressed INIT!!");
				//init();
				
				myNetwork = new Network();
    
    // the network is initialized
    myNetwork.init();
	
	// the clock is started	
	 myTimer = new Timer(myNetwork,this,50);
	 myTimer.start(); 

 
    setBackground(Color.yellow);


				
				for(int k=0;k<count;k++)
					myNetwork.addStation(posArray[k]);
				//Network.stop();
				System.out.println("returned from Init!!");

				posTextField.setText("0");
			}
			
			
			if(label.equals("Clear"))
			{
				count=0;
				myNetwork = new Network();
    
    // the network is initialized
    myNetwork.init();
	
	// the clock is started	
	 myTimer = new Timer(myNetwork,this,50);
	 myTimer.start(); 

 
    setBackground(Color.yellow);
    
    	for(int k=0;k<count;k++)
					myNetwork.addStation(posArray[k]);
				//Network.stop();
				System.out.println("returned from Init!!");

				posTextField.setText("0");


			}
			if(label.equals("AddStation"))
			{
				
				int position = Integer.parseInt(posTextField.getText());
				
				if((posTextField.getText()==null) || (posTextField.getText().equals("")))
				{
					alarmFrame a = new alarmFrame("Enter some value!",400,410);
					a.show();

				}
				else
				{	
				if(!(position>0 && position < 100))
				{	alarmFrame a = new alarmFrame("Give Value between 0 and 100",400,410);
					a.show();
				}
				else
				{
				int n=0;
				for(int k=0;k<count;k++)
					if(Math.abs(position-posArray[k])<15)
					{
						alarmFrame b = new alarmFrame("min. 15 distance",400,410);
						b.show();
						n=1;
					}
				if(n!=1)
				{	
				posArray[count++]=position;
				System.out.println("pressed the button!!");
				System.out.println(position);
				if(position!=0)
				 myNetwork.addStation(Integer.parseInt(posTextField.getText()));       
				}
				}
				}
			}
   	   else
				return false;
		}
		return false;

	} 


}