/**
*Class MagnificentChatApplet
*
*Version 1.0
*
*@author Martin Carlsson
*
*Internet Programming 2 - Course
**/

import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.border.*;

import com.oreilly.servlet.HttpMessage;


/**
*Class MagnificentChatApplet is a threaded GUI class of the Magnificent 
*Chat application that is a subclass to JApplet. 
*It implements the Runnable, ActionListener and CaretListener interfaces.
*
*@version 1.0
*
*@author Martin Carlsson
*
*@see javax.swing.JApplet
*/

public class MagnificentChatApplet extends JApplet implements Runnable, ActionListener, CaretListener {
    
    
    
    private JTextArea privateInputArea;
    private JButton privateSendButton, privateCancelButton;
    
    
   
    private String servletNameAndSession ="/A_8"; //initially the name of the servlet
    private String host;// Host to connect to
   
   
    private Thread thisActivity;// this thread
    
    protected static int ADD = 0, MSG = 1, REMOVE = 2, PRIVATE = 3;// Flags for the different kind of messages
    
    private boolean looping = true;//flag for the run() method 
    private String nameTaken = "***nameTaken***";// If the servlet sends this the name is taken 
   
    //Message area and it's scroll pane
    private JTextArea area; 
    private JScrollPane areaPane;
    
    //List of online users
    private JList list;
    private JScrollPane listPane; 
    
    //Input area and it's scroll pane
    private JTextArea input; 
    private JScrollPane inputPane;
        
    //Private message input area and it's scroll pane
    private JTextArea privateMsgInput; 
    private JScrollPane privateMsgInputPane;
    
    //North, east and west panels
    private JPanel northPanel;
    private JPanel eastPanel; 
    private JLabel listLabel; 
   
    private JMenuBar menuBar;
    private JMenu privateMenu;
    private JMenu helpMenu;
    private JMenuItem privateMsgItem = new JMenuItem("Send message to..");
    private JMenuItem listPrivateMsgItem = new JMenuItem("Send message to.. ");
    private JMenuItem chatHelpItem = new JMenuItem("How to use...");
    private JMenuItem aboutItem = new JMenuItem("About");    
    private JButton send = new JButton("     SEND     ");
    
   
    protected String user = ""; 
    private String[] users;
    private JLabel nickNameLabel;
    private JLabel chatTitle = new JLabel("Magnificent Web Chat");
        
    //Help text
    private String helpText =
    "          BROADCAST\n"+                                    
    "Type in your message and press the\n"+
    "send button to make a broadcast\n"+
    "to all online users.\n\n"+
   
    "          UNICAST\n"+
    "Use the \"Send message\" option under\n"+
    "the private menu - or click on a \n"+ 
    "username in the list of users - to\n"+
    "send a message to a specific user.\n";
    
    //About text
    private String aboutText =
    "Magnificent Web Chat Version 1.0\n"+                                    
    "Created by Martin Carlsson. 2005\n";
  
    
    // Menu that pops up when a client rightclicks in the input field
    JPopupMenu editPopup, listPopup;
    JMenuItem deleteItem = new JMenuItem("Delete");
    JMenuItem selectAllItem = new JMenuItem("Select All");
    JMenuItem cutItem;
    JMenuItem copyItem;
    JMenuItem pasteItem;
    PrivateDialog p;
     
    
    public void init() {
        
        SetLookAndFeel();
        privateSendButton = new JButton("Send");
        privateCancelButton = new JButton("Cancel");
        privateSendButton.addActionListener(this);
        privateCancelButton.addActionListener(this);
        //Container to put everything in
        Container con = getContentPane();
        con.setPreferredSize(new Dimension(100, 100));
        con.setLayout(new BorderLayout());
        
        //Message area
        area = new JTextArea(); 
        area.setToolTipText("Messages sent or received"); 
        area.setLineWrap(true);
        area.setBorder(BorderFactory.createEmptyBorder(4,4,4,4));//Onsynlig border runt meddelandeytan
        area.setEditable(false);
        
        //Holds the scrollbar to the bottom
        DefaultCaret caret = (DefaultCaret) area.getCaret(); 
        caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE); 
        
        //Scroll and message area
        areaPane = new JScrollPane(area);
        areaPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); 
        areaPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); 
        
        //Input area
        input = new JTextArea(2,20);
        input.setToolTipText("Type message here"); 
        DefaultCaret inputCaret = (DefaultCaret) input.getCaret(); 
        inputCaret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE); 
        
        input.setLineWrap(true);//wraps long lines
        input.addKeyListener(kl); //listens to keys pressed
        input.setEditable(true); //made editable
        inputPane = new JScrollPane(input);
        
        input.addCaretListener(this);

        //Private message input area
        privateMsgInput = new JTextArea(2,20);
        privateMsgInput.setToolTipText("Type message here"); 
        DefaultCaret privateMsgInputCaret = (DefaultCaret) privateMsgInput.getCaret();
        privateMsgInputCaret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE); 
        
        privateMsgInput.setLineWrap(true);//wraps long lines
        privateMsgInput.addKeyListener(kl); //listens to keys pressed
        privateMsgInput.setEditable(true); //made editable
        privateMsgInputPane = new JScrollPane(privateMsgInput);
       
        
        //Policys for vertical and horizontal scrolling
        inputPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); 
        inputPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); 
        
        //Creates and adds default actions
        ActionMap aMap = input.getActionMap();
        Action cut = aMap.get(DefaultEditorKit.cutAction);
        Action copy = aMap.get(DefaultEditorKit.copyAction);
        Action paste = aMap.get(DefaultEditorKit.pasteAction);
        
        //Popup menu for rightclicks in the input area
        editPopup = new JPopupMenu();
        cutItem = editPopup.add(cut);
        copyItem = editPopup.add(copy);
        pasteItem = editPopup.add(paste);
        editPopup.add(deleteItem);
        editPopup.addSeparator();
        editPopup.add(selectAllItem);
        
        //Sets the text for the default action menu choises
        cutItem.setText("Cut");
        copyItem.setText("Copy");
        pasteItem.setText("Paste");
        
        //Adds listeners
        deleteItem.addActionListener(this);
        selectAllItem.addActionListener(this);
        privateMsgItem.addActionListener(this);
        listPrivateMsgItem.addActionListener(this);
        chatHelpItem.addActionListener(this);
        aboutItem.addActionListener(this);
        
        
        //Short commands for menu choises
        cutItem.setAccelerator(KeyStroke.getKeyStroke
                                (KeyEvent.VK_X, ActionEvent.CTRL_MASK));
        copyItem.setAccelerator(KeyStroke.getKeyStroke
                                (KeyEvent.VK_C, ActionEvent.CTRL_MASK));
        pasteItem.setAccelerator(KeyStroke.getKeyStroke
                                (KeyEvent.VK_V, ActionEvent.CTRL_MASK));  
        selectAllItem.setAccelerator(KeyStroke.getKeyStroke
                                (KeyEvent.VK_A, ActionEvent.CTRL_MASK));
        deleteItem.setAccelerator(KeyStroke.getKeyStroke
                                (KeyEvent.VK_D, ActionEvent.CTRL_MASK));  
                                     
        //South panel
        JPanel southPanel = new JPanel();
        southPanel.setLayout(new BorderLayout());
        southPanel.add( inputPane,BorderLayout.CENTER);
        send.setPreferredSize(new Dimension(120,30));
        send.setEnabled(false);        
        southPanel.add(send,BorderLayout.EAST);
        
       
        //Fill out panel
        JPanel southWestFill = new JPanel();
        southWestFill.setBackground(Color.decode("#003366"));
        southPanel.add(southWestFill,BorderLayout.WEST);
        
        //Adds the central message area and the south panel
        con.add(areaPane,BorderLayout.CENTER); 
        con.add(southPanel,BorderLayout.SOUTH); 
        
         //Fill out panel
        JPanel southFill = new JPanel();
        southFill.setBackground(Color.decode("#003366"));
        southPanel.add(southFill, BorderLayout.SOUTH);
        
        //Mouselistener for the input area and send button
        input.addMouseListener(mL);
        send.addActionListener(this);
        area.addMouseListener(mL);
        
        //List of online users
        list = new JList();
        list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        list.addMouseListener(mL);
        list.setModel(new DefaultListModel());
        list.setBackground(Color.black);
        list.setForeground(Color.white);        
        listPane = new JScrollPane(list);
        listPane.setBorder(new BevelBorder(BevelBorder.LOWERED));
        DefaultCaret listCaret = (DefaultCaret) area.getCaret(); 
        listCaret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE); 
        
        //East panel
        eastPanel = new JPanel();
        eastPanel.setLayout(new BorderLayout());
        eastPanel.setPreferredSize(new Dimension(120,getSize().height));
        eastPanel.setBackground(Color.decode("#003366"));
        con.add(eastPanel,BorderLayout.EAST); 
       
        //Label to show the number of online users
        listLabel = new JLabel();
        listLabel.setHorizontalAlignment(JLabel.CENTER);
        listLabel.setForeground(Color.decode("#ff9900"));
        listLabel.setBackground(Color.decode("#003366"));
        eastPanel.add(listLabel,BorderLayout.NORTH);
        eastPanel.add(listPane,BorderLayout.CENTER);
        
        //Fill out panels
        JPanel eastRightFill = new JPanel();
        eastRightFill.setBackground(Color.decode("#003366"));
        eastPanel.add(eastRightFill, BorderLayout.EAST);
        JPanel eastLeftFill = new JPanel();
        eastLeftFill.setBackground(Color.decode("#003366"));
        eastPanel.add(eastLeftFill, BorderLayout.WEST);
        JPanel eastBottomFill = new JPanel();
        eastBottomFill.setBackground(Color.decode("#003366"));
        eastPanel.add(eastBottomFill, BorderLayout.SOUTH);
        
      
        //North panel
        northPanel = new JPanel();
        northPanel.setBackground(Color.decode("#003366"));
        northPanel.setLayout(new BorderLayout());
        chatTitle.setFont(new Font("SansSerif", Font.BOLD,25));
        chatTitle.setForeground(Color.white);
        northPanel.add(chatTitle,BorderLayout.CENTER);
        JPanel northLeftPanel = new JPanel();
        northLeftPanel.setBackground(Color.decode("#003366"));
        northPanel.add(northLeftPanel,BorderLayout.WEST);
        con.add(northPanel, BorderLayout.NORTH); 
        
        
        //Fill out panel
        JPanel northEastPanel = new JPanel();
       
        //Label for the users name
        nickNameLabel = new JLabel("- Your nickname: TestNickName"); 
        nickNameLabel.setFont(new Font("SansSerif", Font.BOLD,11));        
        nickNameLabel.setForeground(Color.white);
        nickNameLabel.setPreferredSize(new Dimension(300,15));
        northEastPanel.add(nickNameLabel,BorderLayout.EAST);
        northEastPanel.setBackground(Color.decode("#003366"));
        northPanel.add(northEastPanel,BorderLayout.EAST);
        
        //Menu bar
        menuBar = new JMenuBar();
        menuBar.setBackground(Color.decode("#003366"));
        privateMenu = new JMenu("Private");
        privateMenu.setForeground(Color.decode("#ff9900"));
        helpMenu = new JMenu("Help");
        helpMenu.setForeground(Color.decode("#ff9900"));
        setJMenuBar(menuBar);
        
        //Items for the menu bar
        privateMenu.add(privateMsgItem);
        helpMenu.add(chatHelpItem);
        helpMenu.add(aboutItem);
        menuBar.add(privateMenu);
        menuBar.add(helpMenu);
       
        //Pops up when a user click in the list of online users
        listPopup = new JPopupMenu("Private Message");
        listPopup.setDefaultLightWeightPopupEnabled(false);
        listPopup.add(listPrivateMsgItem);
        
        //West panel
        JPanel westPanel = new JPanel();
        westPanel.setBackground(Color.decode("#003366"));
        con.add(westPanel, BorderLayout.WEST);
        
        thisActivity = new Thread(this);        
    }//end init()
    
    
    /**
    *Called right after the init(). Makes an internal 
    *call to handleUserWelcoming and starts this thread.
    */
    public void start() {
            
        servletNameAndSession = handleUserWelcoming();        
        thisActivity.start(); 
        input.requestFocus(); 
    }
    
    /**
    *Takes care of the welcoming. The client is given the opportunity to log in with any name that is not taken.
    *The name is sent to the servlet to ensure this.
    *Eventually the server sends a valid username and a session back.
    *@return string with the servlet name and the user session id
    */
    public String handleUserWelcoming() {
        
        String serverResponse =  null;
        String[] responseArr = null;
        try {
            user = JOptionPane.showInputDialog(this,"Please enter a nickname(1 - 12 characters)","Welcome to MagnificentChat!",JOptionPane.QUESTION_MESSAGE);
            if(user == null || user.equals("") || user.length() == 0) 
                user = "guest";
            else if(user != null && user.length() > 12)
                while(user.length() > 12 && user != null && user.length() != 0 && !user.equals("")) {
                    user = JOptionPane.showInputDialog(this,"Please try again with no more than 12 characters","Bad input!",JOptionPane.ERROR_MESSAGE);
                    if(user == null || user.equals("") || user.length() == 0) {
                        user = "guest";
                        break;
                    }
                }
    
            while(true) {
                InputStream in = sendToServer(user,ADD);
                BufferedReader data = new BufferedReader(new InputStreamReader(in));
                serverResponse = data.readLine();//Reads the answer from the servlet
                
                if(serverResponse != null && serverResponse.equals(nameTaken)) {// If the name is taken
                    user = JOptionPane.showInputDialog(this,"Try again or leave empty if u wish to be anonymous\n(1 - 12 characters)",user + " is already in use!",JOptionPane.QUESTION_MESSAGE);
                    if(user == null || user.equals("") || user.length() == 0 || user.length() > 12) 
                        user = "guest";
                    
                }
                else if(serverResponse != null) {
                    responseArr=serverResponse.split(",");
                    user=responseArr[0]; 
                    nickNameLabel.setText("- Your nickname: " + user);
                    break; 
                }
            }//while
        } //try
          
        catch (SocketException sE) {
            String problem = "Can't establish a connection to host: \n" + sE.getMessage()+"\n";
            area.append(problem);
            System.err.println(problem);
            try { 
                Thread.sleep(5000);
              
            }
                catch (InterruptedException iE) {
            }
        }
        catch (FileNotFoundException fNfE) {
            String problem = "Resource not found in handleWelcoming: " + fNfE.getMessage();
            area.append(problem);
            System.err.println(problem);
             try { 
                Thread.sleep(5000);
            }
                catch (InterruptedException iE) {
           }
        }
        catch (Exception e) {
            String problem = "Unknown exception in handleWelcoming: " +
            e.getClass().getName() + ": " + e.getMessage();
            area.append(problem);
             try { 
                Thread.sleep(3000);
            }
                catch (InterruptedException iE) {
           }
        }
        return responseArr[1]; 
    } // end handlewelcoming
    
    /**
    *Gets a message from the servlet
    *@return message from the servlet
    */
    String getFromServer() {
        String msgFromServer = null;
        while (msgFromServer == null) {
            try {
                URL url = new URL(getCodeBase(), servletNameAndSession);
                HttpMessage msg = new HttpMessage(url);
              
                // No caching
                msg.setHeader("Expires", "Sat, 6 May 1995 12:00:00 GMT");
               
                msg.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
                
                msg.setHeader("Pragma", "no-cache");
                
                InputStream in = msg.sendGetMessage();
                BufferedReader data = new BufferedReader(new InputStreamReader(in));
                msgFromServer = data.readLine();//Reads the message
                
            }
            catch (SocketException sE) {
               area.append("Can't establish a connection to host:\n" + sE.getMessage()+"\n" + sE.getStackTrace());
                try { 
                    Thread.sleep(5000);
                                
                } 
                catch (InterruptedException iE) { 
                area.append("Connection has timed out");                    
                }
            }
            catch (FileNotFoundException fNfE) {
               area.append("Resource not found\n: " + fNfE.getMessage());
                try { 
                    Thread.sleep(5000);
                                       
                } 
                catch (InterruptedException iE) { 
                }
            }
            catch (Exception e) {
               area.append("Unknown Exception:\n" +
                e.getClass().getName() + ": " + e.getMessage());
                try { 
                    Thread.sleep(3000); 
                    
                } 
            catch (InterruptedException iE) { 
            }
        }
        
    }
    return msgFromServer;
    } //end getFromServer
    
    /**
    *Makes a call at each loop to the getFromServer() method to get the next message.
    */
    public void run() {
       
        while (looping) {
           
            try {
			synchronized(this) {
			while (!looping)
                    wait(); 
                } 
            } 
            catch (InterruptedException e) {	
            } 
            String m = getFromServer();
            if(m.startsWith("users,")) {
                users = m.replaceFirst("users,","").split(",");
                users = sortList(users);
                for(int i=0; i < users.length;i++)
                    users[i] = "  ".concat(users[i]);
                list.setListData(users);
                listLabel.setText("ONLINE: "+ users.length);
            }
            else if(m.startsWith("private message")) {
                String[] myPrivateMsg = m.split(",");
                Frame frame = JOptionPane.getFrameForComponent(this);
                p = new PrivateDialog  (frame,myPrivateMsg[2],myPrivateMsg[1],false, this);
            }
            else if(m.startsWith("No message sent")) {
                showNoMessageSent(m);
            }                
            else {
                area.append(m +"\n");
                area.setCaretPosition(area.getText().length());
            }
        }
    }//end run()
    
    /**
    *Sorts the list of users
    *@param arr array of list elements
    *@return the list sorted
    */
    private String[] sortList(String[] arr) {
        for(int i=0; i<arr.length;i++) {
        
            int index = i;
            int start = index + 1;
            while(start<arr.length) { 
                int w = arr[index].compareTo(arr[start]);
                if(w>0) {
                    String temp=arr[index];
                    arr[index]=arr[start];
                    arr[start]=temp;
                }
                start++;
            }
        }
        return arr;
    }
    /**
    *Verifies if the users list of online users.
    *@param user the user to look for in the list
    *@return true or false, i.e. is the user in the list
    */
    public boolean isUserOnline(String user) {
        boolean online = false;
        for(int i = 0;i < users.length; i++) {
            if(online = users[i].trim().equals(user))
                break;
        }
        return online;
    }
    
    /**
    *Sends private messages
    */
    void sendPrivateMessage() {
        
        String privateMessage="";
        String initialValue = (String)list.getSelectedValue();
        JOptionPane jO = new JOptionPane();
       
        
        if(initialValue==null || initialValue.trim().equals(user))
            initialValue=users[0];
        String sendTo  = (String)JOptionPane.showInputDialog(northPanel,"Who do you wish to send a message to?","Send Private Message!",JOptionPane.QUESTION_MESSAGE, null, users, initialValue);
        sendTo = sendTo.trim();
        if(sendTo != null && sendTo !="" && sendTo.length() > 0 && !sendTo.equals(user.trim()))
            privateMessage  = jO.showInputDialog(northPanel,"Type your message here:","Private Message!",JOptionPane.PLAIN_MESSAGE);
       
        
       
        if(!isUserOnline(sendTo)) {
            Toolkit.getDefaultToolkit().beep(); 
            JOptionPane.showMessageDialog(northPanel, "No message sent" + " to " + sendTo + ". " + sendTo + " is not online!", "Alert", JOptionPane.ERROR_MESSAGE); 
        }
        else if(privateMessage != null && privateMessage !="" && privateMessage.length() > 0)
            sendToServer(sendTo + ","+privateMessage,PRIVATE);
    }
      
    void showNoMessageSent(String m) {
        
        String[] msg = m.split(",");
        if(!msg[1].trim().equals(user.trim())) {
            Toolkit.getDefaultToolkit().beep();
            JOptionPane.showMessageDialog(northPanel, msg[0] + " to " + msg[1] + ". " + msg[1] + " is not online!", "Alert", JOptionPane.ERROR_MESSAGE); 
        }
    }
            
    /**
    Flag method to start or stop the thread
    */
    public synchronized void  setLooping(boolean b) {
    
        looping = b;
        if (looping)
            notify();
    }
    
    /**
	*Sends a post message to the server/servlet
    *@param toSend message to send
    *@param int flag that can be MSG REMOVE ADD or PRIVATE
    *@return inputstream to read the response from the server/servlet
	*/ 	
    InputStream sendToServer(String toSend,int flag) {
    
        try {
            URL url = new URL(getCodeBase(), servletNameAndSession);
            HttpMessage msg = new HttpMessage(url);
            Properties props = new Properties();
           
            if(flag == MSG) 
                props.setProperty("message",toSend);
            else if(flag == REMOVE)
                props.setProperty("removeUser", toSend);
            else if(flag == ADD)
                props.setProperty("addUser", toSend);
            else if(flag == PRIVATE)
                props.setProperty("privateMsg", toSend);
            
           return msg.sendPostMessage(props);
        }
        catch (SocketException e) {
            // Couldn't connect to host
            area.append("Can't connect to host: " + e.getMessage());
            return null;
        }
        catch (FileNotFoundException e) {
            // Couldn't find servlet
            String problem = "Server/servlet not found: " + e.getMessage();
            area.append(problem);
            System.err.println(problem);
            return null;
        }
        catch (Exception e) {
            // Unknown
            String problem = "Unknown problem: " +
            e.getClass().getName() + ": " + e.getMessage();
            area.append(problem);
            System.err.println(problem);
            return null;
        }      
    }
    
    /**
	*Handles events
	*@param event event generated by a client
    */
    public void actionPerformed(ActionEvent event) {
        
        String inputText = input.getText();
       
        if (event.getSource() == send) {
            if(inputText.equals("")) {
                Toolkit.getDefaultToolkit().beep();
              
            }
            else {
                sendToServer(inputText,MSG);
                input.setText("");
            }
            input.requestFocus();
        }
        else if(event.getSource() == privateMsgItem || event.getSource() == listPrivateMsgItem)
            sendPrivateMessage();
        else if(event.getSource() == chatHelpItem) {
            JOptionPane.showMessageDialog(this,helpText, // show help text
			"How to use this chat", JOptionPane.INFORMATION_MESSAGE);
        }
        else if(event.getSource() == aboutItem) {
            JOptionPane.showMessageDialog(this,aboutText, // show about text
            "About", JOptionPane.INFORMATION_MESSAGE);  
        }
        else if(event.getSource() == deleteItem) {
            int start = input.getSelectionStart();
            int end = input.getSelectionEnd();
            input.replaceRange("",start,end);
        }
        else if(event.getSource() == selectAllItem) 
            input.selectAll();
    } 
    
   
    /**
    *Mouse listener adapter class that to listen to client mouse clicks.
     @see java.awt.event.MouseAdapter
    */
    MouseListener mL = new MouseAdapter() {
        
        /**
        *Listens to the input area, message area and the list of online users. 
        *Pops up an edit menu if a client righclick in the input area.
        *Changes the caret position if a client click in the message area.
        *Pops up a menu for sending private messages 
        *if a client clicks in the list of online users 
        *@param mE event generated by a client/user
        */
        public void mousePressed(MouseEvent mE) {
            if(mE.getSource()==input) {
                if(SwingUtilities.isRightMouseButton(mE)) 
                    editPopup.show(mE.getComponent(),mE.getX(),mE.getY()-120);
            }
            else if(mE.getSource() == area)
                area.setCaretPosition(area.getText().length());
            else if(mE.getSource() == list) {
                if(SwingUtilities.isRightMouseButton(mE) || SwingUtilities.isLeftMouseButton(mE))  {
                    listPopup.setLabel("Private menu");
                    listPopup.show(list,list.getX()-45,mE.getY()+10);
                }
            }
        }
    };
    
    /**
	*Adapter class that listens to when a user pressed a key
    @see java.awt.event.KeyAdapter
	*/ 	    
	KeyListener kl = new KeyAdapter() {
		String inputText = "";
        
        /**
        *Listens to the input area.
        *The message is sent to the servlet when a user press Enter.
        @param e event generated by a user
        */
		public void  keyPressed(KeyEvent kE) {
            
            if(kE.getKeyCode() == KeyEvent.VK_ENTER) {
                inputText = input.getText().trim(); 
                if(inputText.equals("")) 
                    Toolkit.getDefaultToolkit().beep();
                else {
                    sendToServer(inputText,MSG);
                    input.setCaretPosition(0);
                    input.setText("");
                }
            }
        } 
        
         /**
        *Listens to the input area for when a key is released.
        *@param kE händelse genererad när en tangent släpps
        */
        public void  keyReleased(KeyEvent kE) {
            
            if(kE.getKeyCode() == KeyEvent.VK_ENTER) 
               input.setText("");
       }
    };
     

    /**
    *Listends to the input area. Used for enabling 
    *the send button if there is any text 
    *in the input area, and - if not - disabling it.
    *@param CaretEvent caret händelse
    */
    public void caretUpdate(CaretEvent cE)   {
        
        if(cE.getMark()==0)
            send.setEnabled(false);
        else if(cE.getMark()==1)
            send.setEnabled(true);
    }

     /**
	*Method for setting a cross platform look and feel.
	*/ 	
    public void SetLookAndFeel() {
  
        try {
            UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName() );
            SwingUtilities.updateComponentTreeUI(this);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }    
    /**
	*Sends a message to the servlet that this user is leaving.
	*/ 	    
    public void stop() {
        sendToServer(user, REMOVE);  
        setLooping(false);
        thisActivity = null;
    }
} // End class MagnificentChatApplet