file: ChatBoard.java

• A CardLayout to organize the functionality of the Applet

• Inner classes to simplify the source code.

• The 1.1 event model to simplify Event, sending Events to only those Components that need them. Note that there is an implicit use of the index of the ActionListener array of the connect button.

• A Thread to pole the server for new messages.

*/

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;//not connected
        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("//" +
				"jinx.umsl.edu/~siegel/java1.1/part5/rmi/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(connection_slot>=0){
                try{
                    get_message=Chatobj.getbroadcast();
                }catch(Exception e){}
                hear.setText(get_message);
            }
            try{
                Thread.currentThread().sleep(1000);
            }catch(InterruptedException e){}
        }
    }//end of run

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==-1)
                     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