// Coded by soff.liangjingbo ASU ID: 20041610209
// as project assigned by Prof.taoyong hunan University
// Course No. EEE-459/591. Winter 2006
import java.applet.applet;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class gbn extends applet implements ActionListener， Runnable
...{
final int window_len_def = 5; //5 // Default values of parameters
final int pack_width_def = 10;//10
final int pack_height_def = 30;
final int h_offset_def = 100; //100
final int v_offset_def = 50; //50
final int v_clearance_def = 300;//300
final int total_packet_def = 20;//20
final int time_out_sec_def = 30;//30
final Color unack_color = Color.red; // Default colors of different packets
final Color ack_color = Color.yellow;
final Color sel_color = Color.green;
final Color roam_pack_color = Color.red;
final Color roam_ack_color = Color.yellow;
final Color dest_color = Color.blue;
int base， nextseq， fps， selected=-1;
//soff edit
int soff_base，soff_nextseq;
boolean timerFlag， timerSleep;
Button send， stop， fast， slow， kill， reset;
Thread gbnThread， timerThread;
Dimension offDimension; // flashing eliminator: double buffering
Image offImage;
Graphics offGraphics;
String statusMsg， strCurrentValues;
packet sender[];
// Declaring properties
int window_len， pack_width， pack_height， h_offset， v_offset， v_clearance，
total_packet， time_out_sec;
public void init()
...{
String strWinLen， strPackWd， strPackHt， strHrOff， strVtOff， strVtClr，
strTotPack， strTimeout;
/**//*
* soff comment
* getParameter what affection???
*
*
* */
strWinLen = getParameter("window_length"); // Start collecting parameters
strPackWd = getParameter("packet_width");
strPackHt = getParameter("packet_height");
strHrOff = getParameter("horizontal_offset");
strVtOff = getParameter("vertical_offset");
strVtClr = getParameter("vertical_clearance");
strTotPack = getParameter("total_packets");
strTimeout = getParameter("timer_time_out");
// Get the values of the parameters into properties.
try ...{
if (strWinLen != null) window_len = Integer.parseInt(strWinLen);
if (strPackWd != null) pack_width = Integer.parseInt(strPackWd);
if (strPackHt != null) pack_height = Integer.parseInt(strPackHt);
if (strHrOff != null) h_offset = Integer.parseInt(strHrOff);
if (strVtOff != null) v_offset = Integer.parseInt(strVtOff);
if (strVtClr != null) v_clearance = Integer.parseInt(strVtClr);
if (strTotPack != null) total_packet = Integer.parseInt(strTotPack);
if (strTimeout != null) time_out_sec = Integer.parseInt(strTimeout);
} catch (Exception e) ...{}
// If parameter is not found， use default values.
window_len = (window_len ＞ 0) ? window_len : window_len_def;
pack_width = (pack_width ＞ 0) ? pack_width : pack_width_def;
pack_height = (pack_height ＞ 0) ? pack_height : pack_height_def;
h_offset = (h_offset ＞ 0) ? h_offset : h_offset_def;
v_offset = (v_offset ＞ 0) ? v_offset : v_offset_def;
v_clearance = (v_clearance ＞ 0) ? v_clearance : v_clearance_def;
total_packet = (total_packet ＞ 0) ? total_packet : total_packet_def;
time_out_sec = (time_out_sec ＞ 0) ? time_out_sec : time_out_sec_def;
base = 0; // Defining base
nextseq = 0; // Defining Next sequence number.
fps = 5;//5 // Defining default Frame per Second.
//soff edit
soff_base=0;
soff_nextseq=0;
sender = new packet[total_packet];
statusMsg = "Ready to run. Press ＇Send New＇ button to start.";
strCurrentValues = "Window Base = "+ base +". Next Sequence No. = "+
nextseq;
// Defining the buttons
send = new Button("Send New");
send.setActionCommand("rdt");
send.addActionListener(this);
stop = new Button("Stop Animation");
stop.setActionCommand("stopanim");
stop.addActionListener(this);
fast = new Button("Faster");
fast.setActionCommand("fast");
fast.addActionListener(this);
slow = new Button("Slower");
slow.setActionCommand("slow");
slow.addActionListener(this);
kill = new Button("Kill Packet");
kill.setActionCommand("kl");
kill.addActionListener(this);
kill.setEnabled(false);
reset = new Button("Reset");
reset.setActionCommand("rst");
reset.addActionListener(this);
// Adding the buttons
/** *//****
*
* add what affection??
*
* add to applet page
*
*/
add(send);
add(stop);
add(fast);
add(slow);
add(kill);
add(reset);
}
public void start()
...{
if (gbnThread==null) // Creating main thread and start it
gbnThread = new Thread(this);
gbnThread.start();
}
public void run()
...{
Thread currenthread = Thread.currentThread();
/** *//***
*
* move packet
*
*/
while (currenthread==gbnThread) // While the animation is running
if (onTheWay(sender)) // Checks if any of the packets are travelling
...{
for (int i=0; i＜total_packet; i++)
if (sender[i]!= null)
if (sender[i].on_way) // If packet is roaming
if (sender[i].packet_pos ＜ (v_clearance-pack_height))
sender[i].packet_pos+=8; // Move packet
else if (sender[i].packet_ack) // If it is moving to destination
...{
if(!sender[i].reached_dest)
this.soff_nextseq++;
sender[i].reached_dest = true;
sender[i].packet_ack = false;
sender[i].packet_pos = pack_height+5;//5
statusMsg = "Packet "+i+" received. Acknowledge sent.";
repaint();
/** *//**
* *soff--comment gbn check receiver work on receiving!
*/
/**//*if (check_upto_n(i)) // Send acknowledgement if all preceeding
{ // packets are received.
sender[i].packet_pos = pack_height+5;
sender[i].packet_ack = false;
statusMsg = "Packet "+i+" received. Acknowledge sent.";
}
else
{
sender[i].on_way = false;
statusMsg = "Packet "+i+" received. No acknowledge sent.";
if (i==selected)
{
selected = -1;
kill.setEnabled(false);
}
}*/
/** *//**
*
* soff edit
*/
// if (check_upto_n(i)) // Send acknowledgement if all preceeding
// { // packets are received.
// if(i＞=base)
// {
// }
// else {
// sender[i].packet_pos=pack_height+5;
// sender[i].packet_ack=false;
//}
if (i+window_len＜total_packet)
//source
//base = i+1;
//soff edit
for(int liang=soff_base;liang＜this.soff_nextseq;liang++)
...{
if(sender[liang].reached_dest)
soff_base++;
else
break;
}
// }
/**//* else
{
sender[i].on_way = false;
statusMsg = "Packet "+i+" received. No acknowledge sent.";
if (i==selected)
{
selected = -1;
kill.setEnabled(false);
}
}*/
}
else if (!sender[i].packet_ack) // acknowledgement
...{
statusMsg = "Packet "+ i +" acknowledge received.";
sender[i].on_way = false;
//source gbn
/**//* for (int n=0; n＜=i; n++)
sender[n].acknowledged = true;*/
/** *//**
* soff edit
*
*/
//source
// for (int n=0; n＜=i; n++)
// if(sender[n].reached_dest)
// sender[n].acknowledged = true;
//soff edit
sender[i].acknowledged=true;
// soff end
if (i==selected)
...{
selected = -1;
kill.setEnabled(false);
}
timerThread = null; //resetting timer thread
if (i+window_len＜total_packet)
//source
//base = i+1;
//soff edit
for(int liang=base;liang＜nextseq;liang++)
...{
if(sender[liang].acknowledged)
base++;
else
break;
}
if (nextseq ＜ base+window_len) send.setEnabled(true);
if (base != nextseq)
...{
statusMsg += " Timer restarted.";
timerThread = new Thread(this);
timerSleep = true;
timerThread.start();
}
else
statusMsg += " Timer stopped.";
}
strCurrentValues = "Window Base = "+ base +". Next Sequence No. = "+
nextseq;
repaint();
try ...{
Thread.sleep(1000/fps); //1000
} catch (InterruptedException e)
...{
System.out.println("Help");
}
}
else
gbnThread = null;
while (currenthread == timerThread)
if (timerSleep)
...{
timerSleep=false;
try ...{
Thread.sleep(time_out_sec*1000);//1000
} catch (InterruptedException e)
...{
System.out.println ("Timer interrupted.");
}
}
else
...{
for (int n=base; n＜base+window_len; n++)
if (sender[n] != null)
if (!sender[n].acknowledged)
...{
sender[n].on_way = true;
sender[n].packet_ack = true;//true
sender[n].packet_pos = pack_height+5;
}
timerSleep = true;
if (gbnThread == null)
...{
gbnThread = new Thread (this);
gbnThread.start();
}
statusMsg = "Packets resent by timer. Timer restarted.";
}
}
public void actionPerformed(ActionEvent e)
...{
String cmd = e.getActionCommand();
if (cmd == "rdt" && nextseq ＜ base+window_len) // Send button is pressed
...{
sender[nextseq] = new packet(true，pack_height+5);
statusMsg = "Packet "+ nextseq +" sent.";
if (base == nextseq)
...{ // i.e. the window is empty and a new data is getting in
statusMsg += " Timer set for packet "+ base +".";
if (timerThread == null)
timerThread = new Thread(this);
timerSleep = true;
timerThread.start();
}
repaint();
nextseq++;
if (nextseq == base+window_len)
send.setEnabled(false);
start();
}
else if (cmd == "fast") // Faster button pressed
...{
fps+=2;
statusMsg = "Simulation speed increased by 2 fps.";
}
else if (cmd == "slow" && fps＞2)
...{
fps-=2;
statusMsg = "Simulation speed decreased by 2 fps.";
}
else if (cmd == "stopanim")
...{
gbnThread = null;
if (timerThread != null)
...{
timerFlag = true;
timerThread = null; // added later
}
stop.setLabel("Resume");
stop.setActionCommand("startanim");
// disableing all the buttons
send.setEnabled(false);
slow.setEnabled(false);
fast.setEnabled(false);
kill.setEnabled(false);
statusMsg = "Simulation paused.";
repaint();
}
else if (cmd == "startanim")
...{
statusMsg = "Simulation resumed.";
stop.setLabel("Stop Animation");
stop.setActionCommand("stopanim");
if (timerFlag)
...{
statusMsg += " Timer running.";
timerThread = new Thread(this);
timerSleep = true;
timerThread.start();
}
// enabling the buttons
send.setEnabled(true);
slow.setEnabled(true);
fast.setEnabled(true);
kill.setEnabled(true);
repaint(); // repainted to show new messages
start();
}
else if (cmd == "kl")
...{
if (sender[selected].packet_ack)
statusMsg = "Packet "+ selected +" destroyed. Timer running for packet "+base+".";
else
statusMsg = "Acknowledgement of packet "+ selected +" destroyed. Timer running for packet "+base+".";
sender[selected].on_way = false;
kill.setEnabled(false);
selected = -1;
repaint();
}
else if (cmd == "rst")
reset_app();
}
public boolean mouseDown(Event e， int x， int y)
...{
int i， xpos， ypos;
i = (x-h_offset)/(pack_width+7);
if (sender[i]!= null)
...{
xpos = h_offset+(pack_width+7)*i;
ypos = sender[i].packet_pos;
if (x＞=xpos && x＜= xpos+pack_width && sender[i].on_way)
...{
if ((sender[i].packet_ack && y＞=v_offset+ypos &&
y＜=v_offset+ypos+pack_height) || ((!sender[i].packet_ack) &&
y＞=v_offset+v_clearance-ypos && y＜=v_offset+v_clearance-ypos+pack_height))
...{
statusMsg = "Packet "+ i +" selected.";
sender[i].selected = true;
selected = i;
kill.setEnabled(true);
}
else
statusMsg = "Click on a moving packet to select.";
}
else
statusMsg = "Click on a moving packet to select.";
}
return true;
}
public void paint(Graphics g) // To eliminate flushing， update is overriden
...{
update(g);
}
public void update(Graphics g)
...{
Dimension d = size();
//Create the offscreen graphics context， if no good one exists.
if ((offGraphics == null) || (d.width != offDimension.width) ||
(d.height != offDimension.height))
...{
offDimension = d;
offImage = createImage(d.width， d.height);
offGraphics = offImage.getGraphics();
}
//Erase the previous image.
offGraphics.setColor(Color.white);
offGraphics.fillRect(0， 0， d.width， d.height);
//drawing window
offGraphics.setColor(Color.black);
offGraphics.draw3DRect(h_offset+base*(pack_width+7)-4， v_offset-3，
(window_len)*(pack_width+7)+1， pack_height+6，true);
//soff edit
offGraphics.setColor(Color.black);
offGraphics.draw3DRect(h_offset+soff_base*(pack_width+7)-4， v_offset-3+v_clearance，
(window_len)*(pack_width+7)+1， pack_height+6，true);
//end
for (int i=0; i＜total_packet; i++)
...{
// drawing the sending row
if (sender[i]==null)
...{
offGraphics.setColor(Color.black);
offGraphics.draw3DRect(h_offset+(pack_width+7)*i， v_offset，
pack_width，pack_height，true);
offGraphics.draw3DRect(h_offset+(pack_width+7)*i， v_offset+v_clearance，
pack_width，pack_height，true);
}
else
...{
if (sender[i].acknowledged)
offGraphics.setColor(ack_color);
else
offGraphics.setColor(unack_color);
offGraphics.fill3DRect (h_offset+(pack_width+7)*i，
v_offset，pack_width，pack_height，true);
// drawing the destination packets
offGraphics.setColor (dest_color);
if (sender[i].reached_dest)
offGraphics.fill3DRect (h_offset+(pack_width+7)*i，
v_offset+v_clearance，pack_width，pack_height，true);
else
offGraphics.draw3DRect (h_offset+(pack_width+7)*i，
v_offset+v_clearance，pack_width，pack_height，true);
// drawing the moving packets
if (sender[i].on_way)
...{
if (i==selected)
offGraphics.setColor (sel_color);
else if (sender[i].packet_ack)
offGraphics.setColor (roam_pack_color);
else
offGraphics.setColor (roam_ack_color);
if (sender[i].packet_ack)
offGraphics.fill3DRect (h_offset+(pack_width+7)*i，
v_offset+sender[i].packet_pos，pack_width，pack_height，true);
else
offGraphics.fill3DRect (h_offset+(pack_width+7)*i，
v_offset+v_clearance-sender[i].packet_pos，pack_width，pack_height，true);
}
}
} // for loop ends
// drawing message boxes
offGraphics.setColor(Color.black);
int newvOffset = v_offset+v_clearance+pack_height;
int newHOffset = h_offset;
offGraphics.drawString(statusMsg，newHOffset，newvOffset+25);
//offGraphics.drawString(strCurrentValues，newHOffset，newvOffset+40);
offGraphics.drawString("Packet"，newHOffset+15，newvOffset+60);
offGraphics.drawString("Acknowledge"，newHOffset+85，newvOffset+60);
offGraphics.drawString("Received Pack"，newHOffset+185，newvOffset+60);
offGraphics.drawString("Selected"，newHOffset+295，newvOffset+60);
offGraphics.drawString("Base = "+base，h_offset+(pack_width+7)*total_packet+10，v_offset+v_clearance/2);
offGraphics.drawString("NextSeq = "+nextseq，h_offset+(pack_width+7)*total_packet+10，v_offset+v_clearance/2+20);
offGraphics.setColor(Color.blue);
offGraphics.drawString("Sender"，h_offset+(pack_width+7)*total_packet+10，v_offset+12);
offGraphics.drawString("Receiver"，h_offset+(pack_width+7)*total_packet+10，v_offset+v_clearance+12);
offGraphics.setColor(Color.gray);
offGraphics.draw3DRect(newHOffset-10，newvOffset+42，360，25，true);
offGraphics.setColor(Color.red);
offGraphics.draw3DRect(h_offset+(pack_width+7)*total_packet+5，v_offset+v_clearance/2-15，80，40，true);
offGraphics.setColor(roam_pack_color);
offGraphics.fill3DRect(newHOffset， newvOffset+50，10，10，true);
offGraphics.setColor(roam_ack_color);
offGraphics.fill3DRect(newHOffset+70， newvOffset+50，10，10，true);
offGraphics.setColor(dest_color);
offGraphics.fill3DRect(newHOffset+170， newvOffset+50，10，10，true);
offGraphics.setColor(sel_color);
offGraphics.fill3DRect(newHOffset+280， newvOffset+50，10，10，true);
g.drawImage(offImage， 0， 0， this);
} // method paint ends
// checks out if an array is on the way to source or destination
public boolean onTheWay(packet pac[])
...{
for (int i=0; i＜pac.length; i++)
if (pac[i] == null)
return false;
else if (pac[i].on_way) return true;
return false;
}
// checkes all the packets before packno. Returns false if any packet has
// not reached destination and true if all the packets have reached destination.
public boolean check_upto_n(int packno)
...{
for (int i=0; i＜packno; i++)
if (!sender[i].reached_dest)
return false;
return true;
}
public void reset_app()
...{
for (int i=0; i＜total_packet; i++)
if (sender[i] != null)
sender[i] = null;
base = 0;
//soff edit
soff_base=0;
nextseq = 0;
selected = -1;
fps = 5;
timerFlag = false;
timerSleep = false;
gbnThread = null;
timerThread = null;
if(stop.getActionCommand()=="startanim") // in case of pause mode， enable all buttons
...{
slow.setEnabled(true);
fast.setEnabled(true);
}
send.setEnabled(true);
kill.setEnabled(false);
stop.setLabel("Stop Animation");
stop.setActionCommand("stopanim");
statusMsg = "Simulation restarted. Press ＇Send New＇ to start.";
repaint();
}
}
class packet
...{
boolean on_way， reached_dest， acknowledged， packet_ack， selected;
int packet_pos;
packet()
...{
on_way = false;
selected = false;
reached_dest = false;
acknowledged = false;
packet_ack = true;
packet_pos =0;
}
packet(boolean onway， int packetpos)
...{
on_way = onway;
selected = false;
reached_dest = false;
acknowledged = false;
packet_ack = true;
packet_pos = packetpos;
}
}