Initial data commit

Task/Chat-server/Groovy/chat-server.groovy

@@ -0,0 +1,156 @@
+class ChatServer implements Runnable {
+    private int port = 0
+    private List<Client> clientList = new ArrayList<>()
+
+    ChatServer(int port) {
+        this.port = port
+    }
+
+    @SuppressWarnings("GroovyInfiniteLoopStatement")
+    @Override
+    void run() {
+        try {
+            ServerSocket serverSocket = new ServerSocket(port)
+            while (true) {
+                Socket socket = serverSocket.accept()
+                new Thread(new Client(socket)).start()
+            }
+        } catch (Exception e) {
+            e.printStackTrace()
+        }
+    }
+
+    private synchronized boolean registerClient(Client client) {
+        for (Client other : clientList) {
+            if (other.clientName.equalsIgnoreCase(client.clientName)) {
+                return false
+            }
+        }
+        clientList.add(client)
+        return true
+    }
+
+    private void deRegisterClient(Client client) {
+        boolean wasRegistered
+        synchronized (this) {
+            wasRegistered = clientList.remove(client)
+        }
+        if (wasRegistered) {
+            broadcast(client, "--- " + client.clientName + " left ---")
+        }
+    }
+
+    private synchronized String getOnlineListCSV() {
+        StringBuilder sb = new StringBuilder()
+        sb.append(clientList.size()).append(" user(s) online: ")
+        def it = clientList.iterator()
+        if (it.hasNext()) {
+            sb.append(it.next().clientName)
+        }
+        while (it.hasNext()) {
+            sb.append(", ")
+            sb.append(it.next().clientName)
+        }
+        return sb.toString()
+    }
+
+    private void broadcast(Client fromClient, String msg) {
+        // Copy client list (don't want to hold lock while doing IO)
+        List<Client> clients
+        synchronized (this) {
+            clients = new ArrayList<>(this.clientList)
+        }
+        for (Client client : clients) {
+            if (client == fromClient) {
+                continue
+            }
+            try {
+                client.write(msg + "\r\n")
+            } catch (Exception ignored) {
+                // empty
+            }
+        }
+    }
+
+    class Client implements Runnable {
+        private Socket socket = null
+        private Writer output = null
+        private String clientName = null
+
+        Client(Socket socket) {
+            this.socket = socket
+        }
+
+        @Override
+        void run() {
+            try {
+                socket.setSendBufferSize(16384)
+                socket.setTcpNoDelay(true)
+                BufferedReader input = new BufferedReader(new InputStreamReader(socket.getInputStream()))
+                output = new OutputStreamWriter(socket.getOutputStream())
+                write("Please enter your name: ")
+                String line
+                while (null != (line = input.readLine())) {
+                    if (null == clientName) {
+                        line = line.trim()
+                        if (line.isEmpty()) {
+                            write("A name is required. Please enter your name: ")
+                            continue
+                        }
+                        clientName = line
+                        if (!registerClient(this)) {
+                            clientName = null
+                            write("Name already registered. Please enter your name: ")
+                            continue
+                        }
+                        write(getOnlineListCSV() + "\r\n")
+                        broadcast(this, "+++ " + clientName + " arrived +++")
+                        continue
+                    }
+                    if (line.equalsIgnoreCase("/quit")) {
+                        return
+                    }
+                    broadcast(this, clientName + "> " + line)
+                }
+            } catch (Exception ignored) {
+                // empty
+            } finally {
+                deRegisterClient(this)
+                output = null
+                try {
+                    socket.close()
+                } catch (Exception ignored) {
+                    // empty
+                }
+                socket = null
+            }
+        }
+
+        void write(String msg) {
+            output.write(msg)
+            output.flush()
+        }
+
+        @Override
+        boolean equals(client) {
+            return (null != client) && (client instanceof Client) && (null != clientName) && clientName == client.clientName
+        }
+
+        @Override
+        int hashCode() {
+            int result
+            result = (socket != null ? socket.hashCode() : 0)
+            result = 31 * result + (output != null ? output.hashCode() : 0)
+            result = 31 * result + (clientName != null ? clientName.hashCode() : 0)
+            return result
+        }
+    }
+
+    static void main(String[] args) {
+        int port = 4004
+        if (args.length > 0) {
+            port = Integer.parseInt(args[0])
+        }
+        new ChatServer(port).run()
+    }
+}