package swingExamples;

import java.awt.Adjustable;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.GridLayout;

import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.SwingConstants;

class ColorSelectPanel extends JPanel
{
  public ColorSelectPanel()
  {
    setLayout(new BorderLayout());
    m_colorPanel = new ColorPanel();
    add(m_colorPanel, BorderLayout.CENTER);
    add(new ScrollPanel(), BorderLayout.SOUTH);
  }
  
  ////// Private data //////
  private ColorPanel m_colorPanel;
  
  ////// Inner classes /////
  class ColorPanel extends JPanel
  {
    ColorPanel()
    {
      setBorder(
          BorderFactory.createLineBorder(Color.BLACK));
    }
  }
  
  class ScrollPanel extends JPanel 
      implements AdjustmentListener
  {
    public ScrollPanel()
    {
      setLayout(new GridLayout(3, 2));
      
      add(m_redLabel);
      m_redScroll.setBackground(Color.RED);
      m_redScroll.setBlockIncrement(BLOCK_INCREMENT);
      m_redScroll.addAdjustmentListener(this);
      add(m_redScroll);
      
      add(m_greenLabel);
      m_greenScroll.setBackground(Color.GREEN);
      m_greenScroll.setBlockIncrement(BLOCK_INCREMENT);
      m_greenScroll.addAdjustmentListener(this);
      add(m_greenScroll);
      
      add(m_blueLabel);
      m_blueScroll.setBackground(Color.BLUE);
      m_blueScroll.setBlockIncrement(BLOCK_INCREMENT);
      m_blueScroll.addAdjustmentListener(this);
      add(m_blueScroll);
      
      changeColor();
    }
    
    // AdjustmentListener required methods
    public void adjustmentValueChanged(AdjustmentEvent evt)
    {
      changeColor();
    }
    
    private void changeColor()
    {
      int red = m_redScroll.getValue();
      int green = m_greenScroll.getValue();
      int blue = m_blueScroll.getValue();
      m_redLabel.setText("" + red);
      m_greenLabel.setText("" + green);
      m_blueLabel.setText("" + blue);
      m_colorPanel.setBackground(
          new Color(red, green, blue));
    }
    
    ////////////// Private Data //////////////////
    private static final int BLOCK_INCREMENT = 16;
    
    private JLabel m_redLabel = 
        new JLabel("0", SwingConstants.CENTER);
    private JLabel m_greenLabel = 
        new JLabel("0", SwingConstants.CENTER);
    private JLabel m_blueLabel = 
        new JLabel("0", SwingConstants.CENTER);
    
    private JScrollBar m_redScroll =
        new JScrollBar(Adjustable.HORIZONTAL, 0, 0, 0, 255);
    private JScrollBar m_greenScroll =
        new JScrollBar(Adjustable.HORIZONTAL, 0, 0, 0, 255);
    private JScrollBar m_blueScroll =
        new JScrollBar(Adjustable.HORIZONTAL, 0, 0, 0, 255);
  }
}

class ColorSelectFrame extends JFrame
{
  public ColorSelectFrame()
  {
    setTitle("Scrollbars");
    setSize(300, 200);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    Container contentPane = getContentPane();
    contentPane.add( new ColorSelectPanel() );
  }
}

public class Scrollbars
{
  public static void main(String[] args)
  {
    ColorSelectFrame frame = new ColorSelectFrame();
    frame.setVisible(true);
  }
}