import java.rmi.*;
public interface Chat extends java.rmi.Remote {
int signIn(String s, int i) throws java.rmi.RemoteException;
void broadcast(String s,int i ) throws java.rmi.RemoteException;
String getbroadcast() throws java.rmi.RemoteException;
}
Server Side file: ChatImpl.java
import java.io.*;
import java.util.*;
import java.net.*;
import java.rmi.*;
import java.rmi.server.UnicastRemoteObject;
public class ChatImpl
extends UnicastRemoteObject
implements Chat
{
private String name;
String [] Users=new String[50];
String hold_last_message;
public ChatImpl(String s) throws RemoteException {
super();
name = s;
}
public int signIn(String s,int i) throws java.rmi.RemoteException{
boolean free_spot=false;
int j=0;
if(i==-1){
while((!free_spot)&(j<50)){
if(Users[j]==null){
Users[j]=s;
free_spot=true;
return j;
}
else
j++;
}
return -1;//Connection refused
}
else{
Users[i]=null;
return -1;
}
}
public void broadcast(String s,int i) throws java.rmi.RemoteException
{hold_last_message=Users[i]+": "+s;
}
public String getbroadcast() throws java.rmi.RemoteException
{return hold_last_message;}
public static void main(String args[])
{
// Create and install a security manager
System.setSecurityManager(new RMISecurityManager());
try {
ChatImpl obj = new ChatImpl("ChatServer");
Naming.rebind("//www.umsl.edu/~siegel/wwwRMI/ChatServer", obj);
System.out.println("ChatServer bound in registry");
} catch (Exception e) {
System.out.println("ChatImpl err: " + e.getMessage());
}
}
}
file: ChatBoard.java
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.rmi.*;
public class ChatBoard extends Applet implements Runnable {
int connection_slot=-1;
boolean am_connected=false;
Chat Chatobj;
ActionTextField sign_in,say,hear;
String chat_name;
ActionButton connect,disconnect,chat;
ActionLabel chat_label;
ActionPanel CardHolder;
Panel sign_in_panel,chat_panel,sign_in_text;
Panel chat_text,sign_in_button,chat_button;
public void init() {
sign_in=new ActionTextField("signin");
say=new ActionTextField("Your Remarks Go Here");
hear=new ActionTextField("Others Will Use This Field");
hear.setEditable(false);
connect =new ActionButton("connect");
disconnect =new ActionButton("disconnect");
chat =new ActionButton("chat");
sign_in_panel=new Panel();
chat_panel=new Panel();
sign_in_text=new Panel();
chat_text=new Panel();
sign_in_button=new Panel();
chat_button=new Panel();
// "The Applet panel"
CardHolder=new ActionPanel();
chat_label=new ActionLabel("Sign In",Label.CENTER);
setLayout(new BorderLayout());
add("Center",CardHolder);
add("North",chat_label);
CardHolder.setLayout(new CardLayout());
CardHolder.add("signin",
sign_in_panel);
CardHolder.add("chat",chat_panel);
sign_in_panel.setLayout(new BorderLayout());
chat_panel.setLayout(new BorderLayout());
sign_in_panel.add("South",sign_in_button);
sign_in_panel.add("Center",sign_in_text);
chat_panel.add("South",chat_button);
chat_panel.add("Center",chat_text);
chat_text.setLayout(new BorderLayout());
sign_in_text.setLayout(new BorderLayout());
chat_text.add("North",say);
chat_text.add("South",hear);
sign_in_text.add("Center",sign_in);
sign_in_button.add(connect);
chat_button.add(disconnect);
chat_button.add(chat);
connect.addActionListener(sign_in);
connect.addActionListener(chat_label);
connect.addActionListener(CardHolder);
disconnect.addActionListener(chat_label);
disconnect.addActionListener(CardHolder);
chat.addActionListener(say);
chat_label.setText("Sign In");
System.out.println("In init");
try {
Chatobj = (Chat)Naming.lookup("//www.umsl.edu/~siegel/wwwRMI/ChatServer");
} catch (Exception e) {
System.out.println("ChatBoard: exception: " +
e.getMessage());
}
}
public void start(){
System.out.println("in start");
new Thread(this).start();
}
public void run(){
String get_message=" ";
while(true){
if(am_connected){
try{
get_message=Chatobj.getbroadcast();
}catch(Exception e){}
hear.setText(get_message);
}
try{
Thread.currentThread().sleep(1000);
}catch(InterruptedException e){}
}
}
class ActionButton extends Button implements ActionListener{
public ActionButton(String s){
super(s);
}
public void actionPerformed(ActionEvent evt){
String s=evt.getActionCommand();
}
}//end of innerclass
class ActionTextField extends TextField implements ActionListener{
String field_holder;
public ActionTextField(String s){
super(s);
}
public void actionPerformed(ActionEvent evt){
String s=evt.getActionCommand();
field_holder=getText().trim();
if(s.equals("connect")){
if(field_holder.length()<4){
setText("Your Chat Name Must Be At Least 4 Letters");
}
else
{
try{
System.out.println(connection_slot);
connection_slot=Chatobj.signIn(field_holder,connection_slot);
System.out.println(connection_slot);
if(connection_slot>=0)
am_connected=true;
else
setText("Connection Refused");
}catch(Exception e){}
}
}
if(s.equals("chat")){
try{
Chatobj.broadcast(field_holder,connection_slot);
}
catch(Exception e){}
}
}
}
class ActionPanel extends Panel implements ActionListener{
public ActionPanel(){
super();
}
public void actionPerformed(ActionEvent evt){
if(connection_slot>=0){
String s=evt.getActionCommand();
if((s.equals("disconnect"))|(s.equals("connect")&((sign_in.getText()).trim().length()>3)))
((CardLayout)getLayout()).next(this);
if(s.equals("disconnect")){
try{Chatobj.signIn(" ",connection_slot);}catch(Exception e){}
connection_slot=-1;
}
}
}
}
class ActionLabel extends Label implements ActionListener{
public ActionLabel(String s,int i){
super(s,i);
}
public void actionPerformed(ActionEvent evt){
String s=evt.getActionCommand();
String hold=sign_in.getText();
if(s.equals("connect")&(connection_slot>=0))setText("Start Chatting");
if(s.equals("disconnect"))setText("Sign In");
}
}
}//end of class