package threads;

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.util.Calendar;
import java.util.Date;
import java.text.DateFormat;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.SwingConstants;

public class ClockApplet extends JApplet implements Runnable
{
  /**
   * The applet init method.
   * Initializes the GUI
   */
  @Override
  public void init()
  {
    EventQueue.invokeLater( new Runnable()
      {
        public void run()
        {
          m_timeLabel = new JLabel("The Time is...", SwingConstants.CENTER);
          m_timeLabel.setFont( new Font("Dialog", Font.BOLD, 16) );
          add(m_timeLabel);
        }
      }
    );
  }
  
  /**
   * The applet start method.
   * Starts up the thread to keep the clock updated.
   */
  @Override
  public void start()
  {
    if (m_clockThread == null)
    {
      m_clockThread = new Thread(this, "Clock");
      m_clockThread.start();
    }
  }
  
  /**
   * The Runnable run method.
   * Keeps the clock updated every second.
   */
  public void run()
  {
    // Loop until m_clockThread is set to null
    while (m_clockThread != null)
    {
      try
      {
        Thread.sleep(1000); // For 1 second
        // Change the label to the current time
        EventQueue.invokeLater( new Runnable()
          {
            // Update the label in the event handling thread.
            public void run()
            {
              Calendar cal = Calendar.getInstance();
              Date date = cal.getTime();
              DateFormat dateFormatter = DateFormat.getTimeInstance();
              m_timeLabel.setText(dateFormatter.format(date));
            }
          }
        );
      }
      catch (InterruptedException e)
      {
        // Ignore
      }
    }
  }
  
  /**
   * The applet stop method
   */
  @Override
  public void stop()
  {
    m_clockThread = null;
    super.stop();
  }
  
  /////// Private data ///////////
  private Thread m_clockThread = null;
  private JLabel m_timeLabel;
}