Java Chat Client Sample Applet

This applet can be used to write a Java Chat Client Application. For thisChat client to work, you need to create a HTML file and embed this applet code inside.

First create the following HTML file and add this code inside the Body tag.

<code> <script> document.write('<applet code="chatclient.class" height=400 width=600>'); n=navigator.appVersion; n=n.substring(0,n.indexOf(' ')); if (navigator.appName.indexOf("Microsoft")==0) { document.write("<param name='java11' value='0'>"); } else if (n<4.06) { document.write("<param name='java11' value='0'>"); } </script>

<param name="host" value="naken.inlink.com"> <param name="port" value="6666"> <param name="channel1" value="Linux Talk"> <param name="channel2" value="FreeBSD"> <param name="channel3" value="Windows Room"> <param name="font" value="MonoSpaced"> <param name="fontsize" value="13">

Java Chat Client Sample Code

import java.awt.*;
import java.applet.*;
import java.net.*;
import java.lang.*;
import java.io.*;

public class chatclient extends Applet implements Runnable
{
Scrollbar vertScroll;
DisplayArea myDisplay;
Thread myThread;
Socket mySocket;
InputStream myInputStream;
BufferedInputStream myBuffInput;
OutputStream myOutputStream;
Graphics gg;
TextField messageText,channelText,nameText;
Button LogButt;
int Online=0;
Checkbox echoBox,beepsBox,yellsBox;
Choice bgChoice,chanChoice,fontsizeChoice,fontChoice;
String YourName="";
int java11=1;

  public void init()
  {
  Panel NorthPanel=new Panel();
  Panel SouthPanel=new Panel();
  Panel EastPanel=new Panel();
  Panel CenterPanel=new Panel();
  int r=0;
  Label chanLabel;

    NorthPanel.setBackground(Color.lightGray);
    SouthPanel.setBackground(Color.lightGray);
    EastPanel.setBackground(Color.lightGray);
    CenterPanel.setBackground(Color.lightGray);

    setLayout(new BorderLayout());
    NorthPanel.setLayout(new FlowLayout(FlowLayout.LEFT));

    SouthPanel.setLayout(new BorderLayout());
    SouthPanel.add("West",new Label("Message:"));
    SouthPanel.add("Center",messageText=new TextField());

    NorthPanel.add(chanLabel=new Label("Channel:",Label.RIGHT));
    NorthPanel.add(chanChoice=new Choice());
    NorthPanel.add(channelText=new TextField("Main",20));
    NorthPanel.add(new Label("Name:",Label.RIGHT));
    NorthPanel.add(nameText=new TextField("",15));

    chanChoice.addItem("---->");
    chanChoice.addItem("Main");
    chanChoice.addItem("Masquerade");
    r=1;
    while(getParameter("channel"+r)!=null)
    { chanChoice.addItem(getParameter("channel"+(r++))); }

    EastPanel.setLayout(new GridLayout(13,1));
    EastPanel.add(new Label("Background Color"));
    EastPanel.add(bgChoice=new Choice());
    EastPanel.add(new Label("Font"));
    EastPanel.add(fontChoice=new Choice());
    EastPanel.add(new Label("Font Size"));
    EastPanel.add(fontsizeChoice=new Choice());
    EastPanel.add(echoBox=new Checkbox("Private Echos",null,false));
    EastPanel.add(yellsBox=new Checkbox("Hush Yells",null,false));
    EastPanel.add(new Button("Who is On"));
    EastPanel.add(new Button("Finger"));
    EastPanel.add(new Button("List Channels"));
    EastPanel.add(new Button("Help"));
    EastPanel.add(LogButt=new Button("Logoff"));

    bgChoice.addItem("Black");
    bgChoice.addItem("White");

    fontChoice.addItem("Dialog");
    fontChoice.addItem("DialogInput");
    fontChoice.addItem("Helvetica");
    fontChoice.addItem("TimesRoman");
    fontChoice.addItem("Courier");
    fontChoice.addItem("Serif");
    fontChoice.addItem("SansSerif");
    fontChoice.addItem("Monospaced");

    for (r=6; r<20; r++) { fontsizeChoice.addItem(""+r); }

    CenterPanel.setLayout(new BorderLayout());
    CenterPanel.add("Center",myDisplay=new DisplayArea());
    CenterPanel.add("East",
          vertScroll=new Scrollbar(Scrollbar.VERTICAL,100,100,0,100));
    vertScroll.show();

    add("South",SouthPanel);
    add("North",NorthPanel);
    add("East",EastPanel);
    add("Center",CenterPanel);

    if (getParameter("fontsize")!=null)
    { myDisplay.fontsize=Integer.parseInt(getParameter("fontsize")); }
      else
    { myDisplay.fontsize=13; }

    if (getParameter("java11")!=null)
    { java11=Integer.parseInt(getParameter("java11")); }

    if (getParameter("font")!=null)
    { myDisplay.font=getParameter("font"); }
      else
    { myDisplay.font="Dialog"; }

    myDisplay.setup(vertScroll.size().width,java11);
    // System.out.println(java11);
    myDisplay.myBar=vertScroll;
    gg=myDisplay.getGraphics();
    fontsizeChoice.select(""+myDisplay.fontsize);
    fontChoice.select(myDisplay.font);
  }

  public void start()
  {
  int l;

    l=logon();
    if (l==0)
    { 
      myThread=new Thread(this);
      myThread.start();
    }
  }

  public int logon()
  {
    try 
    {
      mySocket=new Socket(getParameter("host"),Integer.parseInt(getParameter("port"))); 
      myInputStream=mySocket.getInputStream(); 
      myBuffInput=new BufferedInputStream(myInputStream,2048);
      myOutputStream=mySocket.getOutputStream(); 
      Online=1;
    }
    catch (Exception e) { Online=0; }

    if (Online==1) return 0;

    return 1;
  }

  public void run()
  {
  byte[] in=new byte[2048];
  int r,c=0;
  String myString="";

    if (Online==1)
    { 
      if (getParameter("YourName")!=null)
      {
        nameText.setText(getParameter("YourName"));
        try 
        { myOutputStream.write(convb(".n"+getParameter("YourName")+"\n")); }
        catch (Exception e) {}
        YourName=getParameter("YourName");
      }
    }

    while(true)
    {
      if (Online==1)
      {
        try { c=myBuffInput.read(in,0,2048); } catch (Exception e) { Online=0; }
        for(r=0; r> Private beeps are now on."); }
            else
          { myDisplay.AddText(">> Private beeps are now off."); }
        }
          else
        if (message.startsWith(".e"))
        { echoBox.setState(!echoBox.getState());  }
          else
        if (message.startsWith(".h"))
        {
          message="";
          myDisplay.AddText(">> This is automatic here.");
        }

        myOutputStream.write(convb(message+"\n"));
        messageText.setText("");
      }
        else
      if (e.target==nameText)
      { 
        if (!nameText.getText().equals(YourName))
          myOutputStream.write(convb(".n"+nameText.getText()+"\n"));
        YourName=nameText.getText();
      }
        else
      if (e.target==chanChoice)
      {
        if (chanChoice.getSelectedIndex()!=0)
        {
          myOutputStream.write(convb(".c"+chanChoice.getSelectedItem()+"\n")); 
          channelText.setText(chanChoice.getSelectedItem());
          chanChoice.select(0);
        }
      }
        else
      if (obj.equals("Who is On")) 
      { myOutputStream.write(convb(".w\n")); }
        else
      if (obj.equals("Finger"))
      { myOutputStream.write(convb(".f\n")); }
        else
      if (obj.equals("List Channels"))
      { myOutputStream.write(convb(".a\n")); }
        else
      if (obj.equals("Help"))
      { myOutputStream.write(convb(".he\n")); }
        else
      if (obj.equals("Logoff"))
      { 
        myOutputStream.write(convb(".q\n"));
        Online=0;
        LogButt.setLabel("Log On");
      }
        else
      if (obj.equals("Log On"))
      {
        logon();
        LogButt.setLabel("Logoff");
      }
        else
      if (e.target.toString().indexOf("Private Beeps")>=0)
      { 
        myDisplay.beeps=myDisplay.beeps^1;
        if (myDisplay.beeps==1)
        { myDisplay.AddText(">> Private beeps are now on."); }
          else
        { myDisplay.AddText(">> Private beeps are now off."); }
      }
        else
      if (e.target.toString().indexOf("Hush Yells")>=0)
      { myOutputStream.write(convb(".hu\n")); }
        else
      if (e.target.toString().indexOf("Private Echos")>=0)
      { myOutputStream.write(convb(".e\n")); }
        else
      if (e.target.toString().indexOf("Back To Main")>=0)
      {
        myOutputStream.write(convb(".c0\n"));
        channelText.setText("Main");
      }
        else
      if (e.target==fontsizeChoice)
      {
	myDisplay.fontsize=Integer.parseInt(fontsizeChoice.getSelectedItem());
	myDisplay.recalc();
        myDisplay.paint(gg);
      }
	else
      if (e.target==fontChoice)
      {
	myDisplay.font=fontChoice.getSelectedItem();
	myDisplay.recalc();
        myDisplay.paint(gg);
      }
        else
      if (obj.equals("Black"))
      { 
        myDisplay.fgColor=Color.white; 
        myDisplay.bgColor=Color.black;
        myDisplay.paint(gg);
      }
        else
      if (obj.equals("White"))
      { 
        myDisplay.fgColor=Color.black; 
        myDisplay.bgColor=Color.white;
        myDisplay.paint(gg);
      }
    }
    catch (Exception ex) {}
 
    return false;
  }

  byte[] convb(String myString)
  {
  byte[] myBytes=new byte[2048];
  int r;
   
    for(r=0; r0)
    {
      if (myString.charAt(0)=='>') sflag=1;
        else
      if (myString.charAt(0)=='<') 
      {
        sflag=2; 
        if (beeps!=0) System.out.println((char)7);
      }
        else
      if (myString.charAt(0)=='#') sflag=3;
        else
      if (myString.charAt(0)=='-') sflag=4;
    }
   
    while(myString.length()>0)
    {
      if (fm.stringWidth(myString)=0 && 
            fm.stringWidth(myString.substring(0,r))>d.width-scrollbarSize)
      { r--; }

      spc=0; last=0;

      while((spc=myString.indexOf(' ',spc+1))0) last=spc;
      if (last<=0) { last=r; }
      AddLine(myString.substring(0,last),sflag);
      myString=myString.substring(last,myString.length()).trim();
    }
  }

  public void AddLine(String myString,byte flags)
  {
    BFlags[topptr]=flags;
    Buffer[topptr++]=myString;
    if(topptr==max) topptr=0;

    ScrollRecalc(0);
  }

  public void ScrollRecalc(int i)
  {
  int scrollvis=max;
  int value=0;

/* recalculate scrollbar size */

/* max is maximum number of lines */
/* bsize the current number of text lines in buffer (including on screen) */
/* lastbsize the last bsize */
/* lines is the number of visible text lines on the screen */

/* here */

    if (bsizelines) 
      {
        scrollvis=bsize-lines;
        value=bsize-lines;
      }
        else
      { 
/* beginning state */
	scrollvis=1;
        value=1;
      }

      if (java11==1)
      { myBar.setValues(bsize,lines,0,bsize); }
	else
      { myBar.setValues(value,scrollvis*2,1,value); }

      scrollval=myBar.getValue(); 
    }
      else
    { 
      if (i==1)
      {
        value=bsize-lines;
        scrollvis=bsize-lines;
        if (java11==1)
        { myBar.setValues(bsize,lines,0,bsize); }
  	  else
        { myBar.setValues(value,scrollvis*2,1,value); }
      }
	else
      { myBar.setValue(bsize); }
    }
    
    scrollval=bsize; 
  }

  public void paint(Graphics ggReal)
  {
  Dimension d;
  int r,l;
  int ptr,offset;

    d=this.size();
    if (OffScreen==null)
    {
      OffScreen=createImage(d.width,d.height);
      gg=OffScreen.getGraphics();
    }
    
    gg.setColor(bgColor);
    gg.setFont(myFont);
    gg.fillRect(0,0,d.width,d.height);
    l=0;
    lines=d.height/spacing;
    if (bsize<=lines) { offset=0; }
      else
    { offset=(bsize-lines-myBar.getValue()); }
    myBar.setPageIncrement(lines);
    ptr=topptr-lines-offset;
    while (ptr<0) ptr=ptr+max;

    for (r=0; r0)
          {
            if (BFlags[ptr]==1) { gg.setColor(msColor); }
              else
            if (BFlags[ptr]==2) { gg.setColor(Color.blue); }
              else
            if (BFlags[ptr]==3) { gg.setColor(Color.red); }
              else
            { gg.setColor(fgColor); } 
          }
            else
          { gg.setColor(fgColor); } 
          l=l+spacing;
          gg.drawString(Buffer[ptr],3,l);
        }
        if (++ptr==max) ptr=0;
      }
    }
  ggReal.drawImage(OffScreen,0,0,null);

  }
}