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POJava How to make server wait for three client responses and send out answers
 

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  1. POJava How to make server wait for three client responses and send out answers
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    <p>This is a multi-threaded server client program The objective is to make the server waits for three responses from clients and then roll three dices and check the answers accordingly Currently all I can think of is to use an array list to hold the client responses and if the length of the list becomes three then check the answers and send out the results</p> <p>Running the following codes would not give any errors but if the client enter a number it seems that the client answer does not go into the array list correctly the first client gets result saying that the correct answer is 0 which I guess the game has not started yet so it says 0 the second and third clients get a slew of null returned by the server and disconnected right after I hit enter</p> <p>so the question is why does it keep returning null for client 2 and client 3?</p> <p>Server Code:</p> <pre><code>import java.io.*; import java.net.*; import java.util.*; import java.awt.*; import javax.swing.*; public class GameServer extends JFrame { private JTextArea jta = new JTextArea(); private static int intClient = 0; public static void main(String[] args) { new GameServer(); } public GameServer() { setLayout(new BorderLayout()); add(new JScrollPane(jta), BorderLayout.CENTER); setTitle("Game Server"); setSize(500, 300); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); try { ServerSocket serverSocket = new ServerSocket(8000); jta.append("Server started at " + new Date() + '\n'); jta.setCaretPosition(jta.getDocument().getLength()); while (true) { try { Socket socket = serverSocket.accept(); jta.append("Connected with " + socket.getInetAddress().getHostAddress() + " using socket " + socket.getPort() + '\n'); jta.setCaretPosition(jta.getDocument().getLength()); QuoteServerThread qst = new QuoteServerThread(socket, ++intClient); qst.start(); } catch (Exception ex) { System.err.println(ex); } } } catch (Exception ex) { System.err.println(ex); } } private class QuoteServerThread extends Thread { private Socket socket; private int intClient; private BufferedReader inputFromClient; private PrintWriter outputToClient; QuoteServerThread(Socket parSocket, int parClient) { socket = parSocket; intClient = parClient; } public void run() { if (intClient == 1){ jta.append("Waiting for two more players..." + "\n"); } else if (intClient == 2) { jta.append("Waiting for one more player..." + "\n"); } else if (intClient == 3) { jta.append("Game Starts!" + "\n"); jta.append("Waiting for guesses..." + "\n"); } try { inputFromClient = new BufferedReader(new InputStreamReader(socket.getInputStream())); outputToClient = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()))); } catch (Exception ex) { System.err.println(ex); } while (true) { try { SimpleDiceGame game = new SimpleDiceGame(); String str = inputFromClient.readLine(); jta.append("Player"+intClient+" Guess:" + str + "\n"); ArrayList&lt;String&gt; clientGuessList = new ArrayList&lt;String&gt;(); clientGuessList.add(intClient-1,str); if (clientGuessList.size() == 0){ jta.append("waiting for 3 more answers"); } else if (clientGuessList.size() == 1 ){ jta.append("waiting for 2 more answers"); } else if (clientGuessList.size() == 2 ){ jta.append("waiting for 1 more answer"); } else if (clientGuessList.size() == 3){ game.setDices(); jta.append(game.getDices(1) + " " + game.getDices(2) + " " + game.getDices(3) + "\n"); String result = game.checkAnswer(str,intClient); outputToClient.println("The result is: " + game.getDices(intClient)); outputToClient.println(result); outputToClient.flush(); jta.setCaretPosition(jta.getDocument().getLength()); clientGuessList.removeAll(clientGuessList); } } catch (Exception ex) { try { inputFromClient.close(); outputToClient.close(); socket.close(); jta.append("Disconnected with Player " + intClient + '\n'); jta.setCaretPosition(jta.getDocument().getLength()); break; } catch (Exception ex2) { System.err.println(ex2); } System.err.println(ex); } } intClient--; jta.append("Number of players: " + intClient + "\n"); } } } </code></pre> <p>Client Code:</p> <pre><code>import java.io.*; import java.net.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class GameClient extends JFrame implements Runnable { private JTextField jtf = new JTextField(); private JTextArea jta = new JTextArea(); private BufferedReader fromServer; private PrintWriter toServer; public static void main(String[] args) { new GameClient(); } public GameClient() { JPanel p = new JPanel(); p.setLayout(new BorderLayout()); p.add(new JLabel("Enter quote no."), BorderLayout.WEST); p.add(jtf, BorderLayout.CENTER); jtf.setHorizontalAlignment(JTextField.RIGHT); setLayout(new BorderLayout()); add(p, BorderLayout.NORTH); add(new JScrollPane(jta), BorderLayout.CENTER); jtf.addActionListener(new ButtonListener()); setTitle("Quote Client"); setSize(500, 300); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); Thread th = new Thread(this); th.start(); } public void run() { try { Socket socket = new Socket("localhost", 8000); fromServer = new BufferedReader(new InputStreamReader(socket.getInputStream())); toServer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()))); while (true) { try { String str = fromServer.readLine(); jta.append(str + '\n'); jta.setCaretPosition(jta.getDocument().getLength()); } catch (Exception ex) { fromServer.close(); toServer.close(); socket.close(); System.err.println(ex); } } } catch (Exception ex) { System.err.println(ex); } } private class ButtonListener implements ActionListener { public void actionPerformed(ActionEvent e) { try { String str = jtf.getText().trim(); jtf.setSelectionStart(0); jtf.setSelectionEnd(jtf.getDocument().getLength()); toServer.println(str); toServer.flush(); jta.append("Your guess is: " + str + "\n"); jta.setCaretPosition(jta.getDocument().getLength()); } catch (Exception ex) { System.err.println(ex); } } } } </code></pre> <p>SimpleDiceGame:</p> <pre><code>import java.util.Random; public class SimpleDiceGame { int[] rolledDices = new int[3]; public String checkAnswer(String stringGuess, int playernum){ int intGuess = 0; intGuess = Integer.parseInt(stringGuess); String testResult = null; if (intGuess == rolledDices[playernum-1]) { testResult = "Congratulation! You have won!"; } else { testResult = "Sorry, you missed"; } return testResult; } public void setDices(){ Random r = new Random(); int a = 1+r.nextInt(6); int b = 1+r.nextInt(6); int c = 1+r.nextInt(6); rolledDices[0] = a; rolledDices[1] = b; rolledDices[2] = c; } public int getDices(int playernum){ return rolledDices[playernum-1]; } } </code></pre>
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    1. CODon't have time to provide a full answer (someone will). Meantime does this help? http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Semaphore.html
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      1. USJasper Blues
    2. COUnfortunately, it's not very obvious why your code doesn't work. We can help you find the answer if you tell us specific lines or errors that are giving you trouble, but we can't read your mind. One thing to fix is that the `GameServer` constructor is doing way too much. Move everything from the `try` statement and below into a separate function, which you call right after instantiating the `GameServer`.
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      1. USmusical_coder
    3. COcan't you have a if condition?
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      1. USThusitha Thilina Dayaratne
 

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