stockclient.java

a simple socket price updater

/*Name: Vijay Vasant Dixit
 *UTA ID: 1000554524
 *CSE 5306 - Project-1
 */
/*This class represents a Chat Client Which connects to the Server*/
import java.io.*;
import java.awt.*;
import java.util.*;
import java.lang.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.*;

public class StockClient extends JFrame implements ActionListener,Runnable
{
   JPanel p1;
   JPanel p2;
   JPanel p3;
   JButton end;
   JButton exit;
   JButton request;
   JRadioButton oneSecButton;
   JRadioButton twoSecButton;
   JRadioButton threeSecButton;
   JRadioButton fourSecButton;
   JRadioButton fiveSecButton;
   ButtonGroup group;
   JTextField enterSymbol;
   JTextArea displayPrice;
   JLabel lenterSymbol;
   JLabel ldisplayPrice;
   JLabel lrefreshInterval ;
   JToolBar radioTool;
   JToolBar enterSymbolTool; 
   JToolBar displayPriceTool;
   JToolBar quitTool;
   BorderLayout layout ;
   BorderLayout layout2;
   BorderLayout layout3;
   
   static boolean serverShutdown=false;
   String companySymbol;
   static PriceUpdaterThread updater = null;
   static Thread requestThread = null;
   static Thread thread;
   static int refreshInterval = 3000;
   static Socket tcpSocket;
   static DataInputStream datainputstream;
   static DataOutputStream dataoutputstream;
   static String serverName ="loopback";
   static InetAddress serverIP;
   static int serverTCPPort = 1436;
   static String serverData="";
   
   StockClient()
   {        
       super("Stock Client" );
       //Initialize Panels
       p1= new JPanel();
       p2= new JPanel();
       p3 = new JPanel();
       
       //Initialize Labels
       lenterSymbol = new JLabel ("Enter Company Symbol:");
       ldisplayPrice = new JLabel ("The latest Stock Price:");
       lrefreshInterval = new JLabel("Select the update interval:");
       
       //Initialize toolbars
       radioTool = new JToolBar();
       enterSymbolTool = new JToolBar();
       displayPriceTool = new JToolBar();
       quitTool = new JToolBar();
       enterSymbolTool.setFloatable(false);
       enterSymbolTool.setBorder(BorderFactory.createCompoundBorder
       (
            BorderFactory.createEtchedBorder(),
            BorderFactory.createEmptyBorder(2, 2, 2, 0))
       );
       displayPriceTool.setFloatable(false);
       displayPriceTool.setBorder(BorderFactory.createCompoundBorder
       (
            BorderFactory.createEtchedBorder(),
            BorderFactory.createEmptyBorder(2, 2, 2, 0))
       );
       quitTool.setFloatable(false);
       radioTool.setFloatable(false);

       //Initialize text area and text field
       displayPrice = new JTextArea(1,0);
       enterSymbol = new JTextField("",6);
       Font font = new Font(null, Font.ITALIC, 20);
       displayPrice.setFont(font);
       displayPrice.setForeground(Color.BLUE);
       displayPrice.setBackground(Color.LIGHT_GRAY);
       displayPrice.setEditable(false);
       
       //Initialize Buttons
       end = new JButton();
       exit = new JButton();
       request = new JButton();
       end.setText("END");
       exit.setText("EXIT");
       request.setText("REQUEST");
       end.setMaximumSize(new Dimension(90, 27));
       exit.setPreferredSize(new Dimension(82, 27));
       request.setPreferredSize(new Dimension(85, 27));
       end.addActionListener(this);
       exit.addActionListener(this);
       request.addActionListener(this);
       
       //Initialize radio button
       oneSecButton = new JRadioButton("1 Second");
       oneSecButton.setActionCommand("1 Second");

       twoSecButton = new JRadioButton("2 Second");
       twoSecButton.setActionCommand("2 Second");

       threeSecButton = new JRadioButton("3 Second");
       threeSecButton.setActionCommand("3 Second");
       threeSecButton.setSelected(true);
       
       fourSecButton = new JRadioButton("4 Second");
       oneSecButton.setActionCommand("4 Second");

       fiveSecButton = new JRadioButton("5 Second");
       fiveSecButton.setActionCommand("5 Second");

       //Group the radio buttons.
       group = new ButtonGroup();
       group.add(oneSecButton);
       group.add(twoSecButton);
       group.add(threeSecButton);
       group.add(fourSecButton);
       group.add(fiveSecButton);
       
       JPanel radioPanel = new JPanel(new GridLayout(0, 1));
       radioPanel.add(lrefreshInterval);
       radioPanel.add(oneSecButton);
       radioPanel.add(twoSecButton);
       radioPanel.add(threeSecButton);
       radioPanel.add(fourSecButton);
       radioPanel.add(fiveSecButton);
       
       //Register a listener for the radio buttons.
       oneSecButton.addActionListener(this);
       twoSecButton.addActionListener(this);
       threeSecButton.addActionListener(this);
       fourSecButton.addActionListener(this);
       fiveSecButton.addActionListener(this);
 
       layout = new BorderLayout(5,5);
       layout2 = new BorderLayout(5,5);
       layout3 = new BorderLayout(6,6);  
       
	   //Setting up the layout within the toolbars.
       radioTool.add(radioPanel,null);
       enterSymbolTool.add(lenterSymbol,null);
       enterSymbolTool.add(enterSymbol,null);
       enterSymbolTool.add(request,null);
       displayPriceTool.add(ldisplayPrice,null);
       displayPriceTool.add(displayPrice,null);
       
       p1.setLayout(layout2);
       p1.add(radioTool,BorderLayout.NORTH);
       p1.add(enterSymbolTool,BorderLayout.CENTER);
       p1.add(displayPriceTool,BorderLayout.SOUTH);
       p3.add(end);
       p3.add(exit);
        
       this.setLayout(layout);
       this.add(p1,BorderLayout.NORTH);
       this.add(p3,BorderLayout.SOUTH);
       setSize(500,295);
       setResizable(false);
       setVisible(true);
       enterSymbol.setEnabled( true );
       end.setEnabled(false);
       exit.setEnabled(true);
     
       //Create a new TCP socket to the Server.
       try
       {
           System.out.println(":~> Connecting to server...... \n");
           tcpSocket = new Socket(serverName,serverTCPPort);					
           dataoutputstream = new DataOutputStream(tcpSocket.getOutputStream());    
       }catch(Exception e)
       	{
    	   System.out.println(":~> Error in creating TCP socket "+e+"\n");
    	   System.out.println(":~> The connection has been refused by the server\n");
    	};
       thread = new Thread(this);
       thread.start();
       System.out.println(":~> Starting listening thread on TCP Port...... \n");
   }

     public void actionPerformed( ActionEvent evt)
    {
       
    	 //If the user clicks on REQUEST
         if(evt.getSource()==request)
         {
           if(updater!=null)
        	   updater.stopThread();	 
           end.setEnabled(true); 
	       oneSecButton.setEnabled(false);
	       twoSecButton.setEnabled(false);
	       threeSecButton.setEnabled(false);
	       fourSecButton.setEnabled(false);
	       fiveSecButton.setEnabled(false);
           companySymbol = enterSymbol.getText();
    	   updater = new PriceUpdaterThread(this,refreshInterval,companySymbol);
         }
         
         //If the users clicks on EXIT.
         if(evt.getSource()==exit)
         {
        	if(!serverShutdown) 
            disconnectFromServer();
            System.exit(0);
         }
         
         //If the user clicks on END
         if(evt.getSource()==end)
         {
        	 disconnectFromServer();
        	 end.setEnabled(false);
        	 updater.stopThread();
        	 updater=null;
        	 enterSymbol.setEnabled(true);
        	 oneSecButton.setEnabled(true);
             twoSecButton.setEnabled(true);
             threeSecButton.setEnabled(true);
             fourSecButton.setEnabled(true);
             fiveSecButton.setEnabled(true);
             request.setEnabled(true);
         }
         
         //Conditions for assigning the refresh interval time selected by the user.
         if(evt.getSource()==oneSecButton)
         {
            refreshInterval = 1000;
         }

         if(evt.getSource()==twoSecButton)
         {
        	 refreshInterval = 2000;
         }

         if(evt.getSource()==threeSecButton)
         {
        	 refreshInterval = 3000;
         }

         if(evt.getSource()==fourSecButton)
         {
        	 refreshInterval = 4000;
         }

         if(evt.getSource()==fiveSecButton)
         {
        	 refreshInterval = 5000;
         }
    }
     
    //Thread for listening to incoming data from the server.
    public void run()
    {
    	try{
	        //A while loop to read all the incoming messages from the server.
	        while(thread != null)
	        {
	            datainputstream  = new DataInputStream(tcpSocket.getInputStream());
	            System.out.println(":~> Waiting for stock updates from server on TCP port.......... \n");
	            serverData = datainputstream.readLine();
	            String price="";
	            //The first message received from the server.
	            if(serverData.startsWith("PRICEUPDATE "))
	            {
	                System.out.println(":~> Received Price Update from Server...... "+serverData.substring(12)+"\n");
	                price = serverData.substring(12);
	                displayPrice.setText("                           "+price);
	            }
	            else if(serverData.startsWith("END"))
	            {
	            	serverShutdown=true;
	                System.out.println(":~> Server Shutdown\n");
	                displayPrice.setForeground(Color.RED);
	                displayPrice.setText("           "+"SERVER HAS SHUTDOWN");
	                updater.QuitConnection();
	            }	
	        }
    	}catch(Exception _Exc) 
        {
     	   System.out.println(":~> Connection Problems....");
        }
    }
    
   //Method to send TCP messages to the Server.
   public void sendTCPMessageToServer(String Message)
   {
       System.out.println("Sending TCP message");
       try {
			    dataoutputstream.write(new String(Message).getBytes());	
           }catch(IOException _IoExc) { disconnectFromServer();}
   }
   
   //Method to update the server about an explicit disconnect operation.
   static private void disconnectFromServer()
   {
	   String message = "END\n";
	   try {
		    dataoutputstream.write(new String(message).getBytes());	
      }catch(IOException _IoExc) {}
   }

   //Main method.
   public static void main( String args[] )
   {
	   /*
      if (args.length != 3) 
      {
           System.err.println("Usage:  ChatClient <servername> <serverport>.  Try again.");
           System.exit (-1);
       }
      serverName = args[0];
      serverTCPPort = Integer.parseInt(args[1]);
      */
      
      StockClient application = new StockClient();      
      // The following listener responds to the close event on the window
      application.addWindowListener(
         new WindowAdapter() 
        {
            public void windowClosing( WindowEvent e )
            {            
                System.exit( 0 );
            }
         });
   }
}

/*This class serves the purpose of allowing the client to request 
 * for updates in specified intervals of time.
 */
class PriceUpdaterThread implements Runnable
{
	Thread thread;
	String CMD;
	StockClient Parent;
	String companySymbol = "";
	int refreshInterval = 3000;
	String message="";
        
	PriceUpdaterThread(StockClient stockclient,int refreshInterval,String companySymbol)
	{				
		Parent = stockclient;
		this.refreshInterval=refreshInterval;
		this.companySymbol=companySymbol;
		thread = new Thread(this);
		thread.start();
	}
	
	//Implement the thread
	public void run()
	{
		try {
		while(thread != null)
		{
    		message = "REQUEST "+companySymbol+"\n";
    		Parent.sendTCPMessageToServer(message);
    	    thread.sleep(refreshInterval);  
		}
		}catch(Exception _Exc) 
		{
			System.out.println(":~> Connection problems"+_Exc+"\n");
			QuitConnection();
	    }	
	}
	   
	//A utility method to stop the update thread
	public void stopThread()
	{
		thread.stop();
		thread = null;
	}
	
    //Method to stop the thread and close the TCP socket for a client.
	public void QuitConnection()
	{
		thread.stop();
		thread = null;		
		try {
		Parent.tcpSocket.close();
		}catch(IOException _IOExc) { }
		Parent.tcpSocket = null;	
	}
}