// Example of using threads in Java; also how to use JTextArea

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

public class threadapp extends JApplet implements ActionListener
{
  private MyThread thread1, thread2;
  JButton susp1, susp2, res1, res2, start1, start2;

  static public JTextArea txt;

  public void init ()
  {
    thread1 = new MyThread(1000, 6000);
    thread2 = new MyThread(5000, 5000);
    susp1 = new JButton("Suspend 1");
    susp2 = new JButton("Suspend 2");
    res1 = new JButton("Resume 1");
    res2 = new JButton("Resume 2");
    start1 = new JButton("Start 1");
    start2 = new JButton("Start 2");

    txt = new JTextArea(5, 20);
    txt.setLineWrap(true);
    txt.setEditable(false);

    JScrollPane sp = new JScrollPane(txt);
    sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);

    Container c = getContentPane();
    c.setLayout(new FlowLayout(FlowLayout.CENTER));
    c.add(sp);

    Panel p = new Panel();
    p.setLayout(new GridLayout(3,2));
    p.add(start1);
    p.add(start2);
    p.add(susp1);
    p.add(susp2);
    p.add(res1);
    p.add(res2);
    c.add(p);

    susp1.setEnabled(false);
    susp2.setEnabled(false);
    res1.setEnabled(false);
    res2.setEnabled(false);

    start1.addActionListener(this);
    start2.addActionListener(this);
    res1.addActionListener(this);
    res2.addActionListener(this);
    susp1.addActionListener(this);
    susp2.addActionListener(this);
  }

  public void actionPerformed (ActionEvent e)
  {
    if (e.getSource() == susp1)
      {
	thread1.suspend();
	susp1.setEnabled(false);
	res1.setEnabled(true);
      }
    else if (e.getSource()  == susp2)
      {
	thread2.suspend();
	susp2.setEnabled(false);
	res2.setEnabled(true);
      }
    else if (e.getSource() == res1)
      {
	thread1.resume();
	res1.setEnabled(false);
	susp1.setEnabled(true);
      }
    else if (e.getSource() == res2)
      {
	thread2.resume();
	res2.setEnabled(false);
	susp2.setEnabled(true);
      }
    else if (e.getSource() == start1)
      {
	thread1.start();
	start1.setEnabled(false);
	susp1.setEnabled(true);
      }
    else if (e.getSource() == start2)
      {
	thread2.start();
	start2.setEnabled(false);
	susp2.setEnabled(true);
      }

  }
};

class MyThread extends Thread
  { 
    private int seed;
    private int wait_interval;

    public MyThread (int val, int interval)
    { seed = val; wait_interval = interval;}
    public void run ()
    {
      try {
	while (true)
	  {
	    Thread.sleep (wait_interval);
	    threadapp.txt.append("\n" 
                   + getName() + ":" + seed);
	    seed = seed + 10;
	  }
      }
      catch (InterruptedException exc)
	{
	}
    }
};