Initial commit

.editorconfig

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+root = true
+
+[*]
+end_of_line = lf
+indent_style = space
+indent_size = 4
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

.gitattributes

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+* text=auto eol=lf

.gitignore

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+*.class

LICENSE.txt

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+MIT License
+
+Copyright (c) 2021 GuilhermeWerner
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# JavaChat

Source/Client.java

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+import java.io.*;
+import java.net.*;
+
+public class Client {
+    private Socket clientSocket;
+    private PrintWriter writer;
+    private BufferedReader reader;
+
+    public Client(String serverAddress, int serverPort) throws IOException {
+        clientSocket = new Socket(serverAddress, serverPort);
+        writer = new PrintWriter(clientSocket.getOutputStream(), true);
+        reader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
+    }
+
+    public void start() throws IOException {
+        System.out.println("Connected to server: " + clientSocket.getRemoteSocketAddress());
+
+        new Thread(() -> {
+            try {
+                String inputLine;
+
+                while ((inputLine = reader.readLine()) != null) {
+                    System.out.println(inputLine);
+                }
+            } catch (IOException e) {
+                System.out.println("Error receiving message: " + e);
+            }
+        }).start();
+
+        BufferedReader stdio = new BufferedReader(new InputStreamReader(System.in));
+        String message;
+
+        while ((message = stdio.readLine()) != null) {
+            writer.println(message);
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        Client client = new Client("localhost", 4321);
+        client.start();
+    }
+}

Source/Server.java

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+import java.io.*;
+import java.net.*;
+import java.util.*;
+
+public class Server {
+    private ServerSocket serverSocket;
+    private List<ClientHandler> clients;
+
+    public Server(int port) throws IOException {
+        serverSocket = new ServerSocket(port);
+        clients = new ArrayList<>();
+    }
+
+    public void start() throws IOException {
+        System.out.println("Listening on port: " + serverSocket.getLocalPort());
+
+        while (true) {
+            Socket clientSocket = serverSocket.accept();
+            System.out.println("Client connected: " + clientSocket.getRemoteSocketAddress());
+
+            ClientHandler handler = new ClientHandler(clientSocket, this);
+            clients.add(handler);
+
+            new Thread(handler).start();
+        }
+    }
+
+    public void broadcast(String message, ClientHandler excludeClient) {
+        for (ClientHandler client : clients) {
+            if (client != excludeClient) {
+                client.sendMessage(message);
+            }
+        }
+    }
+
+    public void removeClient(ClientHandler client) {
+        clients.remove(client);
+    }
+
+    public static void main(String[] args) throws IOException {
+        Server server = new Server(4321);
+        server.start();
+    }
+}
+
+class ClientHandler implements Runnable {
+    private Socket clientSocket;
+    private Server server;
+    private PrintWriter writer;
+    private BufferedReader reader;
+
+    public ClientHandler(Socket clientSocket, Server server) throws IOException {
+        this.clientSocket = clientSocket;
+        this.server = server;
+        writer = new PrintWriter(clientSocket.getOutputStream(), true);
+        reader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
+    }
+
+    public void run() {
+        try {
+            String message;
+
+            while ((message = reader.readLine()) != null) {
+                server.broadcast(message, this);
+            }
+        } catch (IOException e) {
+            System.out.println("Error handling client: " + e);
+        } finally {
+            server.removeClient(this);
+
+            try {
+                reader.close();
+                writer.close();
+                clientSocket.close();
+            } catch (IOException e) {
+                System.out.println("Error disconnecting: " + e);
+            }
+        }
+    }
+
+    public void sendMessage(String message) {
+        writer.println(message);
+    }
+}