condition 3 did not satsfying

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Chat (part 16)

Java Multithreading, Level 6, Lesson 15

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Now everything is ready for us to add the necessary methods to the SocketThread class.

1) Add a protected clientHandshake() throws IOException, ClassNotFoundException method. This method will represent the client to the server.
It must:
a) In a loop, use the connection field to receive messages.
b) If a received message is a NAME_REQUEST (the server has requested a name), use the getUserName method to ask the user to enter a username, create a new message that is a MessageType.USER_NAME and contains the entered name, and send the message to the server.
c) If a received message is a MessageType.NAME_ACCEPTED (the server has accepted the name), it means the server has accepted the client name, and you need to inform the main thread, which is eagerly waiting for this news. Do this by passing true to the notifyConnectionStatusChanged() method. Then exit the method.
d) If there is a message of any other type, throw an IOException("Unexpected MessageType").

2) Add a protected void clientMainLoop() throws IOException, ClassNotFoundException method. This method will implement the server's main message-processing loop. Inside the method:
a) Use the connection field to receive a message from the server.
b) If it is a text message (MessageType.TEXT), process it using the processIncomingMessage() method.
c) If the message is a MessageType.USER_ADDED, process it using the informAboutAddingNewUser() method.
d) If the message is a MessageType.USER_REMOVED, process it using the informAboutDeletingNewUser() method.
e) If the client receives a message of some other type, throw an IOException("Unexpected MessageType").
f) Put the code from the previous steps in an infinite loop. The loop will terminate automatically if an error (exception) occurs or the thread on which the loop is running is interrupted.

Requirements:

The clientHandshake() method should use the connection field to send a new message (MessageType.USER_NAME, getUserName()) if the received message is a MessageType.NAME_REQUEST.
The clientHandshake() method should call notifyConnectionStatusChanged(true) and terminate if the received message is a MessageType.NAME_ACCEPTED.
The clientHandshake() method should throw an IOException if the received message is not a MessageType.NAME_ACCEPTED or a MessageType.NAME_REQUEST.
The clientHandshake() method should receive messages from the server as long as the message type is MessageType.NAME_REQUEST.
The clientMainLoop() method should receive messages from the server as long as the message type is MessageType.TEXT, MessageType.USER_REMOVED, or MessageType.USER_ADDED.
The clientMainLoop() method must process the received message using the processIncomingMessage() method if the received message is a MessageType.TEXT.
The clientMainLoop() method must process the received messages using the informAboutAddingNewUser() method if the received message is a MessageType.USER_ADDED.
The clientMainLoop() method must process the received messages using the informAboutDeletingNewUser() method if the received message is a MessageType.USER_REMOVED.
The clientMainLoop() method should throw an IOException if the received message is not a MessageType.TEXT, MessageType.USER_REMOVED, or MessageType.USER_ADDED.

package com.codegym.task.task30.task3008; import java.io.IOException; import java.net.ServerSocket; import java.net.Socket; import java.util.Iterator; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; public class Server { private static Map<String,Connection> connectionMap = new ConcurrentHashMap<>(); public static void main(String[] args) throws IOException { int port = ConsoleHelper.readInt(); ServerSocket serverSocket = new ServerSocket(port); System.out.println("Server is running"); try{ while(true) { Socket socket = serverSocket.accept(); Handler handler = new Handler(socket); handler.start(); } }catch (IOException e){ e.printStackTrace(); serverSocket.close(); } } public static void sendBroadcastMessage(Message message){ Iterator<Map.Entry<String,Connection>> itr = connectionMap.entrySet().iterator(); while(itr.hasNext()){ Map.Entry<String,Connection> pair = itr.next(); Connection connection = pair.getValue(); String user = pair.getKey(); try{ connection.send(message); }catch (IOException e){ System.out.println(user+" Message couldn't sent"); } } } private static class Handler extends Thread{ private Socket socket; public Handler(Socket socket){ this.socket = socket; } @Override public void run() { ConsoleHelper.writeMessage("Connection established with "+socket.getRemoteSocketAddress()); try( Connection connection = new Connection(this.socket)) { String userName = serverHandshake(connection); sendBroadcastMessage(new Message(MessageType.USER_ADDED,userName)); notifyUsers(connection,userName); serverMainLoop(connection,userName); connectionMap.remove(userName); sendBroadcastMessage(new Message(MessageType.USER_REMOVED,userName)); ConsoleHelper.writeMessage("Connection is closed with : "+socket.getRemoteSocketAddress()); }catch (IOException e){ }catch (ClassNotFoundException e){ } } private void notifyUsers(Connection connection, String userName) throws IOException{ for(Map.Entry<String,Connection> pair : connectionMap.entrySet()){ if(!(userName.equals(pair.getKey()))) connection.send(new Message(MessageType.USER_ADDED, pair.getKey())); } } private void serverMainLoop(Connection connection, String userName) throws IOException, ClassNotFoundException { while (true) { try { Message received = connection.receive(); if (received.getType().equals(MessageType.TEXT)) { String m = userName + ": " + received.getData(); sendBroadcastMessage(new Message(MessageType.TEXT, m)); } else { String error = "not text error"; ConsoleHelper.writeMessage(error); } } catch (Exception e) { System.out.println(e.getMessage()); } } } private String serverHandshake(Connection connection) throws IOException,ClassNotFoundException{ while(true) { connection.send(new Message(MessageType.NAME_REQUEST)); Message response = connection.receive(); if (response.getType().equals(MessageType.USER_NAME)) { String data = response.getData(); if (data != null && !(data.equals(""))) { if(!(connectionMap.containsKey(data))) { connectionMap.put(data, connection); connection.send(new Message(MessageType.NAME_ACCEPTED)); return data; } } } } } } }

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季军

Level 38 , Shanghai, China

19 February 2020, 15:50

It seems that the type of the message could be null, I don't know why but this helps me pass validation

Mateusz

Level 36 , Wroclaw, Poland

17 February 2020, 12:35

New record in this task Never give up -> challenge accepted ;)

Mateusz

Level 36 , Wroclaw, Poland

17 February 2020, 12:47

I tried to do this task using the Message variable in all possible conditions (if else), but I fell. New day, new thinks :) I changed the Message instance to MessageType and "voilà" (fr). and this is solution: while (!isClientConnected()) { MessageType message = connection.receive().getType(); if (message != MessageType.NAME_REQUEST && message != MessageType.NAME_ACCEPTED) throw new IOException("Unexpected MessageType"); if (message.equals(MessageType.NAME_REQUEST)) connection.send(new Message(MessageType.USER_NAME, getUserName())); if (message.equals(MessageType.NAME_ACCEPTED)) { notifyConnectionStatusChanged(true); return; } }

+13

Alexandre Lalancette

Level 41 , Quebec, Canada

17 January 2020, 20:01

Did you resolve it? If so, what was the issue? I'm stuck in the same place!