Send conected clients via udp

src/main/java/org/example/ClientApp.java

@@ -20,6 +20,7 @@ public class ClientApp extends JFrame {
     private JTextArea chatArea;
     private JTextField messageField;
     private JButton sendButton;
+    private JButton listButton;
 
     private Socket tcpSocket;
     private DatagramSocket udpSocket;
@@ -54,6 +55,15 @@ public class ClientApp extends JFrame {
         });
         bottomPanel.add(sendButton, BorderLayout.EAST);
 
+        listButton = new JButton("List");
+        listButton.addActionListener(new ActionListener() {
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                requestConnectedClients();
+            }
+        });
+        bottomPanel.add(listButton, BorderLayout.WEST);
+
         add(bottomPanel, BorderLayout.SOUTH);
 
         setVisible(true);
@@ -81,6 +91,7 @@ public class ClientApp extends JFrame {
             public void run() {
                 try {
                     String serverMessage;
+                    out.println(clientName);
                     while ((serverMessage = in.readLine()) != null) {
                         chatArea.append(serverMessage + "\n");
                     }
@@ -127,7 +138,7 @@ public class ClientApp extends JFrame {
         String message = messageField.getText().trim();
         if (!message.isEmpty()) {
             out.println(clientName + ": " + message);
-            //sendUDPMessage(clientName + ": " + message);
+            // sendUDPMessage(clientName + ": " + message);
             messageField.setText("");
             chatArea.append("You: " + message + "\n");
         }
@@ -144,6 +155,10 @@ public class ClientApp extends JFrame {
         }
     }
 
+    private void requestConnectedClients() {
+        sendUDPMessage("GET_CLIENTS");
+    }
+
     public static void main(String[] args) {
         if (args.length > 0) {
             SwingUtilities.invokeLater(new Runnable() {

src/main/java/org/example/ServerApp.java

@@ -6,6 +6,7 @@ import java.io.InputStreamReader;
 import java.io.PrintWriter;
 import java.net.DatagramPacket;
 import java.net.DatagramSocket;
+import java.net.InetAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.ArrayList;
@@ -86,12 +87,15 @@ public class ServerApp {
         public void run() {
             try {
                 byte[] buffer = new byte[1024];
-                DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
 
                 while (true) {
+                    DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
                     datagramSocket.receive(packet);
-                    String message = new String(packet.getData(), 0, packet.getLength());
+                    String request = new String(packet.getData(), 0, packet.getLength());
-                    broadcastTCPMessage(message, null);
+
+                    if (request.equals("GET_CLIENTS")) {
+                        sendClientList(packet.getAddress(), packet.getPort());
+                    }
                 }
             } catch (IOException e) {
                 e.printStackTrace();
@@ -99,6 +103,20 @@ public class ServerApp {
                 datagramSocket.close();
             }
         }
+
+        private void sendClientList(InetAddress address, int port) {
+            StringBuilder clientList = new StringBuilder();
+            for (ClientHandler client : clients) {
+                clientList.append(client.getClientName()).append("\n");
+            }
+            byte[] buffer = clientList.toString().getBytes();
+            DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, port);
+            try {
+                datagramSocket.send(packet);
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
     }
 
     private class ClientHandler extends Thread {
@@ -106,11 +124,16 @@ public class ServerApp {
         private DatagramSocket datagramSocket;
         private BufferedReader in;
         private PrintWriter out;
+        private String clientName;
 
         public ClientHandler(Socket socket) {
             this.clientSocket = socket;
         }
 
+        public String getClientName() {
+            return clientName;
+        }
+
         @Override
         public void run() {
             try {
@@ -118,6 +141,9 @@ public class ServerApp {
                 out = new PrintWriter(clientSocket.getOutputStream(), true);
                 datagramSocket = new DatagramSocket();
 
+                clientName = in.readLine();
+                broadcastTCPMessage(clientName + " entrou no chat.", this);
+
                 String clientMessage;
                 while ((clientMessage = in.readLine()) != null) {
                     broadcastTCPMessage(clientMessage, this);
@@ -143,7 +169,8 @@ public class ServerApp {
         public void sendUDPMessage(String message) {
             try {
                 byte[] buffer = message.getBytes();
-                DatagramPacket packet = new DatagramPacket(buffer, buffer.length, clientSocket.getInetAddress(), UDP_PORT);
+                DatagramPacket packet = new DatagramPacket(buffer, buffer.length, clientSocket.getInetAddress(),
+                        UDP_PORT);
                 datagramSocket.send(packet);
             } catch (IOException e) {
                 e.printStackTrace();