Server Socket GUI Freezes

**mrhid6** · 09-29-2011, 02:14 PM

Hello there i have a server/client socket program an i decided i needed a gui for the server side i made a basic gui with a start and stop jbutton but soon as i press start the program runs fine but then i cant stop it ? here is code::

GUI:

Java Code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ServerInterFace extends JFrame{   
    JButton button,stbutton;
    EchoServer server;
    Container c;
    handler handle;

    public ServerInterFace(){

        super("Login form");
        handle =new handler();
        c=getContentPane();
        c.setLayout(new FlowLayout());

        //extra classes
        handle =new handler();
        button=new JButton("Start");
        stbutton=new JButton("Stop");

        //adding actionlistener to the button
        button.addActionListener(handle);
        stbutton.addActionListener(handle);
        c.add(button);
        c.add(stbutton);
        //visual
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(200,130);
    }

    class handler implements ActionListener
    {
        //must implement method
        //This is triggered whenever the user clicks the login button
        public void actionPerformed(ActionEvent ae)
        {
            //checks if the button clicked
            if(ae.getSource()==button)
            {
                EchoServer server = new EchoServer();
            }else if(ae.getSource()==stbutton){
                server.stopserver();
                server=null;
            }
        }//method

    }//inner class
} 


SERVER:
import java.net.*; 
import java.io.*;
import javax.swing.*;

public class EchoServer 
{         
    ServerSocket m_ServerSocket; 
    Mysql db;
    public boolean stopped = false;

    public EchoServer()  
    { 

        db=new Mysql();
        try  
        { 
            // Create the server socket. 
            m_ServerSocket = new ServerSocket(12111); 
        } 
        catch(IOException ioe) 
        { 
            System.out.println("Could not create server socket at 12111. Quitting."); 
            System.exit(-1); 
        } 

        System.out.println("Listening for clients on 12111"); 

        // Successfully created Server Socket. Now wait for connections. 
        int id = 0; 
        while(true) 
        {                         
            try 
            { 
                // Accept incoming connections. 
                Socket clientSocket = m_ServerSocket.accept(); 

                // accept() will block until a client connects to the server. 
                // If execution reaches this point, then it means that a client 
                // socket has been accepted. 

                // For each client, we will start a service thread to 
                // service the client requests. This is to demonstrate a 
                // multithreaded server, although not required for such a 
                // trivial application. Starting a thread also lets our 
                // EchoServer accept multiple connections simultaneously. 

                // Start a service thread 

                ClientServiceThread cliThread = new ClientServiceThread(clientSocket, id++); 
                cliThread.start(); 
            } 
            catch(IOException ioe) 
            { 
                System.out.println("Exception encountered on accept. Ignoring. Stack Trace :"); 
                ioe.printStackTrace(); 
            } 
        } 
    } 

    public void stopserver(){
        m_ServerSocket = null;
        System.exit(-1); 
    }

    public static void main (String[] args) 
    { 
        new EchoServer();     
    } 

    class ClientServiceThread extends Thread 
    { 
        Socket m_clientSocket;         
        int m_clientID = -1; 
        boolean m_bRunThread = true;

        ClientServiceThread(Socket s, int clientID) 
        { 
            m_clientSocket = s; 
            m_clientID = clientID; 

        } 

        public void run() 
        {       
            SwingUtilities.invokeLater(this);
                // Obtain the input stream and the output stream for the socket 
                // A good practice is to encapsulate them with a BufferedReader 
                // and a PrintWriter as shown below. 
            BufferedReader in = null;  
            PrintWriter out = null; 

            // Print out details of this connection 
            System.out.println("Accepted Client : ID - " + m_clientID + " : Address - " +  
                m_clientSocket.getInetAddress().getHostName()); 

            try 
            {                                 
                in = new BufferedReader(new InputStreamReader(m_clientSocket.getInputStream())); 
                out = new PrintWriter(new OutputStreamWriter(m_clientSocket.getOutputStream())); 

                // At this point, we can read for input and reply with appropriate output. 

                // Run in a loop until m_bRunThread is set to false 
                while(m_bRunThread && in!=null) 
                {                     
                    // read incoming stream 
                    String clientCommand = in.readLine(); 

                    String[] msg = clientCommand.split(",");

                    String temp_cmd1 = msg[0];
                    String[] temp_cmd2 = temp_cmd1.split("=");
                    String cmd = temp_cmd2[1];

                    if(cmd.equalsIgnoreCase("quit")) 
                    { 
                        // Special command. Quit this thread 
                        m_bRunThread = false;    
                        System.out.print("Stopping client thread for client : " + m_clientID); 
                    }
                    if(cmd.equalsIgnoreCase("login")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 
                        String[] temp_uname = msg[1].split("=");
                        String uname = temp_uname[1];

                        String[] temp_pass = msg[2].split("=");
                        String pwd = temp_pass[1];
                        //out.println(uname+":"+pass);
                        //out.flush();
                        int taskman = db.loginplayer(uname,pwd);
                        if(taskman>0){
                            out.println("cmd=loginsuc,pid=1");
                            out.flush();
                        }else{
                            out.println("cmd=loginfail");
                            out.flush();
                        }

                    }
                    if(cmd.equalsIgnoreCase("logout")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        db.logoutuser(playerid);

                    }
                    if(cmd.equalsIgnoreCase("getplayerdata")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 

                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        out.println(db.getplayerdata(playerid));
                        out.flush();

                    }
                    if(cmd.equalsIgnoreCase("updateppos")){
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        String[] temp_xpos = msg[2].split("=");
                        int xpos = Integer.parseInt(temp_xpos[1]);

                        String[] temp_ypos = msg[3].split("=");
                        int ypos = Integer.parseInt(temp_ypos[1]);

                        db.updateplayerpos(xpos,ypos,playerid);
                    }

                } 
            } 
            catch(Exception e) 
            { 
                //e.printStackTrace(); 
            } 
            finally 
            { 
                // Clean up 
                try 
                {                     
                    in.close(); 
                    out.close(); 
                    m_bRunThread=false;
                    m_clientSocket.close(); 
                    System.out.println("Client : ID - " + m_clientID +"...Stopped"); 
                } 
                catch(IOException ioe) 
                { 
                    ioe.printStackTrace(); 
                } 
            } 
        } 
    } 
}

**Fubarable** · 09-29-2011, 02:15 PM

You will want to read/study this tutorial on Concurrency in Swing. It will explain what your problem is, and how to fix it.

**mrhid6** · 09-29-2011, 04:32 PM

ok i have read through the thing you sent me but still cant work out how to solve my problem?!

**Tolls** · 09-29-2011, 05:31 PM

Inside your action listener you do:

Java Code:

                EchoServer server = new EchoServer();

Inside which you have an infinite loop.
All of this is done on the EDT (the Swing thread).
This means no other events can ever be run...hence you lock up.
So read the tutorial Fubarable posted and try to understand how to deal with this sort of thing in your app.

**mrhid6** · 09-29-2011, 05:43 PM

Ok so i have read the tutorial again but still dont understand what to do to make it work

**Fubarable** · 09-29-2011, 08:17 PM

Originally Posted by mrhid6

Ok so i have read the tutorial again but still dont understand what to do to make it work

We can't help you if you don't tell us how you've changed your code according to the recommendations from the tutorial and why it is now not working now -- we can't read minds. Please show some effort, at least in how you ask questions here.

**mrhid6** · 09-30-2011, 11:27 AM

I know i have to use a swingworker but i just dont know where to put it in my code

SERVER:

Java Code:

import java.net.*; 
import java.io.*;
import javax.swing.*;

public class EchoServer extends Thread
{         
    ServerSocket m_ServerSocket; 
    Mysql db;
    public boolean stopped = false;

    public EchoServer()  
    { 

        db=new Mysql();
        try  
        { 
            // Create the server socket. 
            m_ServerSocket = new ServerSocket(12111); 
        } 
        catch(IOException ioe) 
        { 
            System.out.println("Could not create server socket at 12111. Quitting."); 
            System.exit(-1); 
        } 
        System.out.println("Listening for clients on 12111"); 

        // Successfully created Server Socket. Now wait for connections. 
        SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    int id = 0; 
                    try{
                        while(stopped!=true) 
                        {                         
                            try 
                            { 
                                // Accept incoming connections. 
                                Socket clientSocket = m_ServerSocket.accept(); 

                                // accept() will block until a client connects to the server. 
                                // If execution reaches this point, then it means that a client 
                                // socket has been accepted. 

                                // For each client, we will start a service thread to 
                                // service the client requests. This is to demonstrate a 
                                // multithreaded server, although not required for such a 
                                // trivial application. Starting a thread also lets our 
                                // EchoServer accept multiple connections simultaneously. 

                                // Start a service thread 

                                ClientServiceThread cliThread = new ClientServiceThread(clientSocket, id++); 
                                cliThread.start(); 
                            } 
                            catch(IOException ioe) 
                            { 
                                System.out.println("Exception encountered on accept. Ignoring. Stack Trace :"); 
                                ioe.printStackTrace(); 
                            } 
                        } 
                    }catch(Exception e){

                    }
                } 
            });
            return;
    }

    public void stopserver(){
        m_ServerSocket = null;
        System.exit(-1); 
    }

    public static void main (String[] args) 
    { 
        new EchoServer();     
    } 

    class ClientServiceThread extends Thread 
    { 
        Socket m_clientSocket;         
        int m_clientID = -1; 
        boolean m_bRunThread = true;

        ClientServiceThread(Socket s, int clientID) 
        { 
            m_clientSocket = s; 
            m_clientID = clientID; 

        } 

        public void run() 
        {       
            // Obtain the input stream and the output stream for the socket 
            // A good practice is to encapsulate them with a BufferedReader 
            // and a PrintWriter as shown below. 
            BufferedReader in = null;  
            PrintWriter out = null; 

            // Print out details of this connection 
            System.out.println("Accepted Client : ID - " + m_clientID + " : Address - " +  
                m_clientSocket.getInetAddress().getHostName()); 

            try 
            {        
                in = new BufferedReader(new InputStreamReader(m_clientSocket.getInputStream())); 
                out = new PrintWriter(new OutputStreamWriter(m_clientSocket.getOutputStream())); 

                // At this point, we can read for input and reply with appropriate output. 

                // Run in a loop until m_bRunThread is set to false 
                while(m_bRunThread && in!=null) 
                {                     
                    // read incoming stream 
                    String clientCommand = in.readLine(); 

                    String[] msg = clientCommand.split(",");

                    String temp_cmd1 = msg[0];
                    String[] temp_cmd2 = temp_cmd1.split("=");
                    String cmd = temp_cmd2[1];

                    if(cmd.equalsIgnoreCase("quit")) 
                    { 
                        // Special command. Quit this thread 
                        m_bRunThread = false;    
                        System.out.print("Stopping client thread for client : " + m_clientID); 
                    }
                    if(cmd.equalsIgnoreCase("login")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 
                        String[] temp_uname = msg[1].split("=");
                        String uname = temp_uname[1];

                        String[] temp_pass = msg[2].split("=");
                        String pwd = temp_pass[1];
                        //out.println(uname+":"+pass);
                        //out.flush();
                        int taskman = db.loginplayer(uname,pwd);
                        if(taskman>0){
                            out.println("cmd=loginsuc,pid=1");
                            out.flush();
                        }else{
                            out.println("cmd=loginfail");
                            out.flush();
                        }

                    }
                    if(cmd.equalsIgnoreCase("logout")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        db.logoutuser(playerid);

                    }
                    if(cmd.equalsIgnoreCase("getplayerdata")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 

                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        out.println(db.getplayerdata(playerid));
                        out.flush();

                    }
                    if(cmd.equalsIgnoreCase("updateppos")){
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        String[] temp_xpos = msg[2].split("=");
                        int xpos = Integer.parseInt(temp_xpos[1]);

                        String[] temp_ypos = msg[3].split("=");
                        int ypos = Integer.parseInt(temp_ypos[1]);

                        db.updateplayerpos(xpos,ypos,playerid);
                    }

                } 
            } 
            catch(Exception e) 
            { 
                //e.printStackTrace(); 
            } 
            finally 
            { 
                // Clean up 
                try 
                {                     
                    in.close(); 
                    out.close(); 
                    m_bRunThread=false;
                    m_clientSocket.close(); 
                    System.out.println("Client : ID - " + m_clientID +"...Stopped"); 
                } 
                catch(IOException ioe) 
                { 
                    ioe.printStackTrace(); 
                } 
            } 
        }
    } 
}

GUI:

Java Code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ServerInterFace extends JFrame{   
    JButton button,stbutton;
    JTextArea textArea;
    EchoServer server;
    Container c;
    handler handle;

    public ServerInterFace(){

        super("Login form");
        handle =new handler();
        c=getContentPane();
        c.setLayout(new FlowLayout());

        //extra classes
        handle =new handler();
        textArea = new JTextArea();
        textArea.setPreferredSize(new Dimension(170,100));
        textArea.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black));
        textArea.append("Hello");
        JScrollPane scrollPane = new JScrollPane(textArea); 
        textArea.setEditable(false);
        button=new JButton("Start");
        stbutton=new JButton("Stop");

        //adding actionlistener to the button
        button.addActionListener(handle);
        stbutton.addActionListener(handle);
        c.add(textArea);
        c.add(button);
        c.add(stbutton);
        //visual
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(200,200);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {  //Note 1
                public void run() {
                    ServerInterFace window = new ServerInterFace();
                    window.setVisible(true);
                }
            });
    }
    class handler implements ActionListener
    {
        //must implement method
        //This is triggered whenever the user clicks the login button
        public void actionPerformed(ActionEvent ae)
        {
            //checks if the button clicked
            if(ae.getSource()==button)
            {
                try{
                    EchoServer server = new EchoServer();
                }catch(Exception e){
                    System.out.println(e);
                }
            }else if(ae.getSource()==stbutton){
                server.stopserver();
                server=null;
            }
        }//method

    }//inner class
}

**Norm** · 09-30-2011, 03:34 PM

where to put it in my code

The problem is that the EchoServer's constructor does not return.
You can either change the constructor so that it starts its code on a new thread and returns
Or change the call to the constructor to be in a new thread.

You want the listener to return after calling the EchoServer's constructor.

**mrhid6** · 09-30-2011, 05:19 PM

ok so how do i go about doing

change the constructor so that it starts its code on a new thread and returns

**Norm** · 09-30-2011, 05:23 PM

In the constructor create a thread with a run method that calls a method that does what the code in the current constructor does, start the thread and exit from the constructor. The thread will then execute what the constructor used to do.

**mrhid6** · 09-30-2011, 05:28 PM

i know this might sound a bit weird but do u think u can write it because i am very new to threads and sockets

**Norm** · 09-30-2011, 05:29 PM

Try writing a very small simple program that creates and starts a Thread. Have that thread's run method print out a message to show it that it executed.

Search on the forum for lots of sample code.

**mrhid6** · 09-30-2011, 05:39 PM

YAY got it to work :) here is final code::

GUI:

Java Code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ServerInterFace extends JFrame{   
    JButton button,stbutton;
    JTextArea textArea;
    EchoServer server;
    Container c;
    handler handle;

    public ServerInterFace(){

        super("Login form");
        handle =new handler();
        c=getContentPane();
        c.setLayout(new FlowLayout());

        //extra classes
        handle =new handler();
        textArea = new JTextArea();
        textArea.setPreferredSize(new Dimension(170,100));
        textArea.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black));
        textArea.append("Hello");
        JScrollPane scrollPane = new JScrollPane(textArea); 
        textArea.setEditable(false);
        button=new JButton("Start");
        stbutton=new JButton("Stop");

        //adding actionlistener to the button
        button.addActionListener(handle);
        stbutton.addActionListener(handle);
        c.add(textArea);
        c.add(button);
        c.add(stbutton);
        //visual
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(200,200);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {  //Note 1
                public void run() {
                    ServerInterFace window = new ServerInterFace();
                    window.setVisible(true);
                }
            });
    }
    class handler implements ActionListener
    {
        //must implement method
        //This is triggered whenever the user clicks the login button
        public void actionPerformed(ActionEvent ae)
        {
            EchoServer server = new EchoServer();
            //checks if the button clicked
            if(ae.getSource()==button)
            {
                try{
                    server.start();
                }catch(Exception e){
                    System.out.println(e);
                }
            }else if(ae.getSource()==stbutton){
                server.stopserver();
            }
        }//method

    }//inner class
}

SERVER:

Java Code:

import java.net.*; 
import java.io.*;
import javax.swing.*;

public class EchoServer extends Thread
{         
    ServerSocket m_ServerSocket; 
    Mysql db;
    public boolean stopped = false;

    public void run()  
    { 
        startserver();
        return;
    }

    public void startserver(){

        db=new Mysql();
        try  
        { 
            // Create the server socket. 
            m_ServerSocket = new ServerSocket(12111); 
        } 
        catch(IOException ioe) 
        { 
            System.out.println("Could not create server socket at 12111. Quitting."); 
            System.exit(-1); 
        } 
        System.out.println("Listening for clients on 12111"); 
        int id = 0; 
        while(stopped!=true) 
        {                         
            try 
            { 
                // Accept incoming connections. 
                Socket clientSocket = m_ServerSocket.accept(); 

                // accept() will block until a client connects to the server. 
                // If execution reaches this point, then it means that a client 
                // socket has been accepted. 

                // For each client, we will start a service thread to 
                // service the client requests. This is to demonstrate a 
                // multithreaded server, although not required for such a 
                // trivial application. Starting a thread also lets our 
                // EchoServer accept multiple connections simultaneously. 

                // Start a service thread 

                ClientServiceThread cliThread = new ClientServiceThread(clientSocket, id++); 
                cliThread.start(); 
            } 
            catch(IOException ioe) 
            { 
                System.out.println("Exception encountered on accept. Ignoring. Stack Trace :"); 
                ioe.printStackTrace(); 
            } 
        } 
    }

    public void stopserver(){
        stopped = true;
        m_ServerSocket = null;
        System.exit(-1); 
    }

    public static void main (String[] args) 
    { 
        new EchoServer();     
    } 

    class ClientServiceThread extends Thread 
    { 
        Socket m_clientSocket;         
        int m_clientID = -1; 
        boolean m_bRunThread = true;

        ClientServiceThread(Socket s, int clientID) 
        { 
            m_clientSocket = s; 
            m_clientID = clientID; 

        } 

        public void run() 
        {       
            // Obtain the input stream and the output stream for the socket 
            // A good practice is to encapsulate them with a BufferedReader 
            // and a PrintWriter as shown below. 
            BufferedReader in = null;  
            PrintWriter out = null; 

            // Print out details of this connection 
            System.out.println("Accepted Client : ID - " + m_clientID + " : Address - " +  
                m_clientSocket.getInetAddress().getHostName()); 

            try 
            {        
                in = new BufferedReader(new InputStreamReader(m_clientSocket.getInputStream())); 
                out = new PrintWriter(new OutputStreamWriter(m_clientSocket.getOutputStream())); 

                // At this point, we can read for input and reply with appropriate output. 

                // Run in a loop until m_bRunThread is set to false 
                while(m_bRunThread && in!=null) 
                {                     
                    // read incoming stream 
                    String clientCommand = in.readLine(); 

                    String[] msg = clientCommand.split(",");

                    String temp_cmd1 = msg[0];
                    String[] temp_cmd2 = temp_cmd1.split("=");
                    String cmd = temp_cmd2[1];

                    if(cmd.equalsIgnoreCase("quit")) 
                    { 
                        // Special command. Quit this thread 
                        m_bRunThread = false;    
                        System.out.print("Stopping client thread for client : " + m_clientID); 
                    }
                    if(cmd.equalsIgnoreCase("login")){

                        String[] temp_uname = msg[1].split("=");
                        String uname = temp_uname[1];

                        String[] temp_pass = msg[2].split("=");
                        String pwd = temp_pass[1];
                        //out.println(uname+":"+pass);
                        //out.flush();
                        System.out.println("Client " + m_clientID +" Says :" + cmd+" user:"+uname); 
                        int taskman = db.loginplayer(uname,pwd);
                        if(taskman>0){
                            out.println("cmd=loginsuc,pid=1");
                            out.flush();
                        }else{
                            out.println("cmd=loginfail");
                            out.flush();
                        }

                    }
                    if(cmd.equalsIgnoreCase("logout")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        db.logoutuser(playerid);

                    }
                    if(cmd.equalsIgnoreCase("getplayerdata")){
                        System.out.println("Client " + m_clientID +" Says :" + cmd); 

                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        out.println(db.getplayerdata(playerid));
                        out.flush();

                    }
                    if(cmd.equalsIgnoreCase("updateppos")){
                        String[] temp_pid = msg[1].split("=");
                        int playerid = Integer.parseInt(temp_pid[1]);

                        String[] temp_xpos = msg[2].split("=");
                        int xpos = Integer.parseInt(temp_xpos[1]);

                        String[] temp_ypos = msg[3].split("=");
                        int ypos = Integer.parseInt(temp_ypos[1]);

                        db.updateplayerpos(xpos,ypos,playerid);
                    }

                } 
            } 
            catch(Exception e) 
            { 
                //e.printStackTrace(); 
            } 
            finally 
            { 
                // Clean up 
                try 
                {                     
                    in.close(); 
                    out.close(); 
                    m_bRunThread=false;
                    m_clientSocket.close(); 
                    System.out.println(" Client : ID - " + m_clientID +"...Stopped"); 
                } 
                catch(IOException ioe) 
                { 
                    ioe.printStackTrace(); 
                } 
            } 
        }
    } 
}