package hangThread;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;

/**
 * This is a frame which illustrates the problems associated with trying to
 * do large amounts of work from within the Event Dispatch Thread.
 */

public class HangThreadExample extends JFrame
{
  public HangThreadExample()
  {
    setTitle("Hang Thread Example");
    setSize(200, 200);
    Container contentPane = getContentPane();
    contentPane.setLayout(new BorderLayout());
    contentPane.add( new ButtonPanel(), BorderLayout.CENTER );
    contentPane.add(m_progressLabel, BorderLayout.SOUTH);
  }
  
  private void doWork()
  {
    try
    {
      Thread.sleep(10000); // represents a long operation of some kind.
    }
    catch (InterruptedException ie)
    {
      ie.printStackTrace();
    }
  }
  
  private void setProgress(final String text)
  {
    m_progressLabel.setText(text);
  }
  
  class ButtonPanel extends JPanel implements ActionListener
  {
    ButtonPanel()
    {
      setBackground(Color.blue);
      m_clickMeButton.addActionListener(this);
      add(m_clickMeButton);
      
      m_nowClickMeButton.addActionListener( new ActionListener()
      {
        public void actionPerformed(ActionEvent ev)
        {
          ButtonPanel.this.setBackground(Color.yellow);
        }
      }
      );
      m_nowClickMeButton.setEnabled(false);  // Disable for now
      add(m_nowClickMeButton);
    }
    
    public void actionPerformed(ActionEvent ev)
    {
      m_clickMeButton.setEnabled(false);
      Color oldColor = getBackground(); // Save color
      setBackground(Color.red);
      m_nowClickMeButton.setEnabled(true);
      
      setProgress("Working...");
      doWork();
      setProgress("Done");
      
      m_clickMeButton.setEnabled(true);
    }
  }
  
  public static void main(String[] args)
  {
    HangThreadExample frame = new HangThreadExample();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
  
  private JButton m_clickMeButton = new JButton("Click me!");
  private JButton m_nowClickMeButton = new JButton("Now try to click me!");
  private JLabel m_progressLabel = new JLabel(" ", SwingConstants.CENTER);
}