// How to use Sockets to create Client programs in Java

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

public class client extends JFrame
{
  Socket sock;
  DataInputStream sis;
  DataOutputStream sos;
  JTextArea display;
  JButton Stopcom;
  JButton Sendcom;
  JTextField Comtext;

  public client ()
  {
    super("Client Program:");
    display = new JTextArea(5, 25);
    display.setLineWrap(true);
    display.setEditable(false);
    display.setBackground(Color.green);

    JScrollPane jsp = new JScrollPane(display);
    jsp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);

    Stopcom = new JButton("Stop");
    Sendcom = new JButton("Send");
    Comtext = new JTextField(15);

    Panel p = new Panel();
    p.setLayout(new FlowLayout());
    p.add(Stopcom);
    p.add(Sendcom);
    
    Container c = getContentPane();
    c.setLayout(new BorderLayout());
    c.add(Comtext, BorderLayout.NORTH);
    c.add(jsp, BorderLayout.CENTER);
    c.add(p, BorderLayout.SOUTH);

    setSize(300,150);
    setLocation(300,300);
    setVisible(true);
    EventHandler ev = new EventHandler(this);
    Stopcom.addActionListener(ev);
    Sendcom.addActionListener(ev);
    addWindowListener(new WindowAdapter() 
		      {
			public void windowClosing(WindowEvent e)
			  {
			    System.exit(0);
			  }
		      });
  }
  
  public void runClient()
  {

    try 
      {
	sock = new Socket(InetAddress.getLocalHost(), 5500);
	display.append("Contacted server at 5500\n");

	sis = new DataInputStream(sock.getInputStream());
	sos = new DataOutputStream(sock.getOutputStream());
	
	Sendcom.setEnabled(true);
	String reply = sis.readUTF();
	display.append( reply + "\n");
	if (reply.equalsIgnoreCase("Refused"))
	  {
	    display.setBackground(Color.red);
	    Sendcom.setEnabled(false);
	  }
      }
    catch (IOException e)
      {
	e.printStackTrace();
      }

  }

  public static void main (String args[])
  {
    client c = new client();
    c.runClient();
  }

}

class EventHandler implements ActionListener
{
  client c;
  EventHandler (client x)
  {
    c = x;
  }

  public void actionPerformed(ActionEvent a)
  {
    try
      {
	if (a.getSource() == c.Stopcom)
	  {
	    if (c.Sendcom.isEnabled())  // indicates valid client
	      {
		c.sos.writeUTF("STOP");
		c.display.append(c.sis.readUTF() + "\n");
		c.sock.close();
	      }
	    System.exit(1);
	  }
	if (a.getSource() == c.Sendcom)
	  {
	    c.sos.writeUTF(c.Comtext.getText());
	    c.display.append( c.sis.readUTF() + c.sis.readInt() + "\n");
	  }
      }
    catch (IOException i)
      {
	c.display.append("Error: " + i.toString() + "\n");
	System.exit(1);
      }
  }
}