package potentialCorruption;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.concurrent.atomic.AtomicInteger;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingConstants;
import javax.swing.WindowConstants;

/**
 * This class invokes multiple threads which (incorrectly) update the contents
 * of a Swing component from outside the event thread.
 */

public class PotentialCorruptor extends JFrame
{
  /**
   * Main entry point for Java application
   */
  public static void main(String[] args)
  {
    PotentialCorruptor frame = new PotentialCorruptor();
    frame.setVisible(true);
  }
  
  /**
   * Construct the class
   */
  public PotentialCorruptor()
  {
    setTitle("Potential Corruptor Example");
    setDefaultCloseOperation(WindowConstants.HIDE_ON_CLOSE);
    
    Container panel = getContentPane();
    panel.setLayout( new BorderLayout() );
    m_buttonPanel = new ButtonPanel();
    panel.add(m_buttonPanel, BorderLayout.CENTER);
    
    m_statusLabel.setFont( new Font( "dialog", Font.BOLD, 14 ) );
    panel.add(m_statusLabel, BorderLayout.SOUTH);
    pack();
  }
  
  /**
   * Button Panel
   */
  class ButtonPanel extends JPanel
  {
    ButtonPanel()
    {
      setBackground(Color.blue);
      m_startButton.addActionListener( new ActionListener()
        {
          public void actionPerformed(ActionEvent ev)
          {
            setBackground(Color.red);
            m_turnYellowButton.setEnabled(true);
            m_textArea.setText("");
            m_statusLabel.setText("Running...");
            for (int i = 1; i < TOTAL_THREADS; i++)
            {
              Thread thread = new CorruptorThread("Thread " + i);
              thread.start();
            }
          }
        }
      );
      add(m_startButton);
      
      m_turnYellowButton.addActionListener( new ActionListener()
        {
          public void actionPerformed(ActionEvent ev)
          {
            ButtonPanel.this.setBackground(Color.yellow);
          }
        }
      );
      m_turnYellowButton.setEnabled(false);  // Disable for now
      add(m_turnYellowButton);
      
      add( new JScrollPane(m_textArea) );
    }
    
    /**
     * The thread to run
     */
    class CorruptorThread extends Thread
    {
      CorruptorThread(String name)
      {
        super(name);
      }
      
      public void run()
      {
        int threadNumber = m_threadCount.incrementAndGet();
        m_statusLabel.setText("Running (" + threadNumber + " threads)");
        for (int i = 0; i < 50; i++)
        {
          try
          {
            Thread.sleep(1);
            update("" + i);
          }
          catch (InterruptedException ie)
          {
            ie.printStackTrace();
          }
        }
        
        update("Thread Done");
        threadNumber = m_threadCount.decrementAndGet();
        m_statusLabel.setText("Running (" + threadNumber + " threads)");
        if (threadNumber == 0)
        {
          m_statusLabel.setText("Done!");
          m_buttonPanel.setBackground(Color.blue);
          m_turnYellowButton.setEnabled(false);
        }
      }
      
      private void update(String text)
      {
        String temp = m_textArea.getText();
        temp += "\n" + getName() + ": " + text;
        m_textArea.setText(temp);
      }
    }
  }
    
  private ButtonPanel m_buttonPanel;
  private JButton m_startButton = new JButton("Start (Turn Red)");
  private JButton m_turnYellowButton = new JButton("Now Turn Yellow");
  private JTextArea m_textArea = new JTextArea(10, 20);
  private JLabel m_statusLabel = new JLabel("", SwingConstants.CENTER);
  private static final int TOTAL_THREADS = 10;
  private AtomicInteger m_threadCount = new AtomicInteger(0);
}