//: c14:Counter2.java
// From Thinking in Java, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// A responsive user interface with threads
// <applet code=Counter2 width=300 height=100>
// </applet>
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

class SeparateSubTask extends Thread {
  private int count = 0;
  private Counter2 c2;
  private boolean runFlag = true;
  public SeparateSubTask(Counter2 c2) {
    this.c2 = c2;
    start();
  }
  public void invertFlag() { runFlag = !runFlag;}
  public void run() {
    while (true) {
     try {
      sleep(100);
     } catch (InterruptedException e){}
     if(runFlag) 
       c2.t.setText(Integer.toString(count++));
    }
  }
} 

public class Counter2 extends JApplet {
  JTextField t = new JTextField(10);
  private SeparateSubTask sp = null;
  private JButton 
    onOff = new JButton("Toggle"),
    start = new JButton("Start");
  public void init() {
    Container cp = getContentPane();
    cp.setLayout(new FlowLayout());
    cp.add(t);
    start.addActionListener(new StartL());
    cp.add(start);
    onOff.addActionListener(new OnOffL());
    cp.add(onOff);
  }
  class StartL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      if(sp == null)
        sp = new SeparateSubTask(Counter2.this);
    }
  }
  class OnOffL implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      if(sp != null)
        sp.invertFlag();
    }
  }
  public static void main(String[] args) {
    JApplet applet = new Counter2();
    JFrame frame = new JFrame("Counter2");
    frame.addWindowListener(
      new WindowAdapter() {
        public void windowClosing(WindowEvent e) {
          System.exit(0);
        }
      });
    frame.getContentPane().add(applet);
    frame.setSize(300, 100);
    applet.init();
    applet.start();
    frame.setVisible(true);
  }
} ///:~