Chapter 31 Exercise 10, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

31.10 (Multiple client chat) Write a program that enables any number of clients to chat. Implement one server that serves all the clients, as shown in Figure 31.22. Name the client Exercise31_10Client and the server Exercise31_10Server.

import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.NoSuchElementException;
import java.util.Scanner;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Exercise10s extends JFrame {
 
 private static final long serialVersionUID = 1L;
 private JTextArea jta = new JTextArea();
 private ArrayList<NewClient> clients = new ArrayList<>();
 
 public Exercise10s() {
  setLayout(new BorderLayout());
     jta.setLineWrap(true);  
     jta.setWrapStyleWord(true);
     jta.setEditable(false);
     jta.setFont(new Font(Font.MONOSPACED, Font.BOLD, 12));
     jta.append(new Date() + " Startig Chat Server\n");
     JScrollPane jsp = new JScrollPane(jta);
     
  jsp.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {
   @Override
   public void adjustmentValueChanged(AdjustmentEvent e) {
    e.getAdjustable().setValue(e.getAdjustable().getMaximum());
   }
  });
     
     add(jsp, BorderLayout.CENTER);
  setTitle("Exercise10s");
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(800, 500);
  setLocationRelativeTo(null);
  setVisible(true);

  
  try {
   @SuppressWarnings("resource")
   ServerSocket serverSocket = new ServerSocket(8000);
   while(true) {
    Socket socket = serverSocket.accept();
    NewClient newClient = new NewClient(socket);
    clients.add(newClient);
   }
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
 
 class NewClient implements Runnable {
  private Socket socket;
  private PrintWriter toClient;
  
  public NewClient(Socket socket) {
   this.socket = socket;
   Thread thread = new Thread(this);
   thread.start();
  }
  
  public void run() {
   try {
    @SuppressWarnings("resource")
    Scanner fromClient = new Scanner(socket.getInputStream());
    toClient = new PrintWriter(socket.getOutputStream());
    jta.append(new Date() + " Connection from  " + socket + "\n");
    while(true) {
     String text = fromClient.nextLine();
     jta.append(new Date() + " " + text + "\n");
     for (NewClient newClient : clients) {
      newClient.send(text);
     }
    }
   } catch (IOException e) {
    e.printStackTrace();
   } catch (NoSuchElementException e) {    
   }
  }
  
  public void send(String text) {
   Calendar time = new GregorianCalendar();
   toClient.printf("%02d:%02d:%02d " + text + "\n", time.get(Calendar.HOUR_OF_DAY), time.get(Calendar.MINUTE), time.get(Calendar.SECOND));
   toClient.flush();
  }
  
 }

 public static void main(String[] args) {
  new Exercise10s();
 }
}

import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.NoSuchElementException;
import java.util.Scanner;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class Exercise10c extends JFrame {
 
 private static final long serialVersionUID = 1L;
 private JTextArea jta = new JTextArea();
 private PrintWriter toServer;
 private JTextField jTextField1 = new JTextField();
 private JTextField jTextField2 = new JTextField();
 
 public Exercise10c() {
  setLayout(new BorderLayout(5, 5));
  JPanel mainPanel = new JPanel(new BorderLayout(5, 5));
  mainPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
  
  jta.setWrapStyleWord(true);
     jta.setLineWrap(true);
     jta.setEditable(false);
     jta.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 14));
     JScrollPane jsp = new JScrollPane(jta);

  jsp.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {
   @Override
   public void adjustmentValueChanged(AdjustmentEvent e) {
    e.getAdjustable().setValue(e.getAdjustable().getMaximum());
   }
  });
     
  
     mainPanel.add(jsp, BorderLayout.CENTER);
     
     JPanel jPanel1 = new JPanel(new GridLayout(2, 1, 5, 5));
     JPanel jPanel2 = new JPanel(new BorderLayout(5, 5));
     jPanel2.add(new JLabel("Name "), BorderLayout.WEST);     
     jPanel2.add(jTextField1, BorderLayout.CENTER);
     JPanel jPanel3 = new JPanel(new BorderLayout(5, 5));
     jPanel3.add(new JLabel("Enter text "), BorderLayout.WEST);
     jPanel3.add(jTextField2, BorderLayout.CENTER);
     jPanel1.add(jPanel2);
     jPanel1.add(jPanel3);
     mainPanel.add(jPanel1, BorderLayout.SOUTH);
     add(mainPanel, BorderLayout.CENTER);
     
     jTextField2.addActionListener(new ActionListener() {
   
   @Override
   public void actionPerformed(ActionEvent e) {
    if(jTextField1.getText().equals("")) {
     JOptionPane.showMessageDialog(null, "Enter your name!", "Waring", JOptionPane.WARNING_MESSAGE);
     jTextField1.requestFocus();
    } else if (jTextField2.getText().equals("")) {
     JOptionPane.showMessageDialog(null, "Enter message!", "Waring", JOptionPane.WARNING_MESSAGE);
     jTextField2.requestFocus();
    } else {
     toServer.println(jTextField1.getText() + ": " + jTextField2.getText());
     toServer.flush();
     jTextField2.setText("");
    }
   }
  });
     
  setTitle("Exercise10c");
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(800, 500);
  setLocationRelativeTo(null);
  setVisible(true);
  
  try {
   Socket socket = new Socket("localhost", 8000); 
   toServer = new PrintWriter(socket.getOutputStream());
   new ReceiveMessage(socket);
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
 
 class ReceiveMessage implements Runnable {
  private Socket socket;
  public ReceiveMessage(Socket socket) {
   this.socket = socket;
   Thread thread = new Thread(this);
   thread.start();
  }
  public void run() {
   try {
    @SuppressWarnings("resource")
    Scanner fromServer = new Scanner(socket.getInputStream());
    while(true) {
     String text = fromServer.nextLine();
     jta.append(text + "\n");
    }
   } catch (IOException e) {
    e.printStackTrace();
   } catch (NoSuchElementException e) {    
   }
  }
 }

 public static void main(String[] args) {
  new Exercise10c();
 }
}