import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

public class FarbSlider implements java.awt.event.ActionListener {
    protected JFrame f;
    protected Scrollbar sRed, sGreen, sBlue;
    protected Label lRed, lGreen, lBlue;
    protected int r, g, b;

    public FarbSlider()
    {
      f = new JFrame("Farb-Slider");  // create window object

      final Container pane=f.getContentPane();  // needs to be final for use in inner classes

      pane.setLayout(new GridLayout(4, 2));  // set a grid layout

      pane.setBackground(Color.black);  // default background
      r = g = b = 0;                    // for the default RGB values

      // set up red label
      lRed = new Label("Rot: 0");
      lRed.setBackground(Color.red);

      // add red label
      pane.add(lRed);

      // set up slider for red value
      sRed = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 256);

      // register event handler for changing red slider
      sRed.addAdjustmentListener(
        new AdjustmentListener() {
          public void adjustmentValueChanged(AdjustmentEvent e) {
            r = e.getValue(); // get the slider value
            lRed.setText("Rot: " + r);  // update label text
            pane.setBackground(new Color(r, g, b));  // update field color
          }
        }
      );

      // add red slider
      pane.add(sRed);


      // the following repetition of code for the other sliders
      // can of course be avoided but the resulting code
      // is more complex (need to identify event source)

      lGreen = new Label("Gruen: 0");
      lGreen.setBackground(Color.green);
      pane.add(lGreen);

      sGreen = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 256);
      sGreen.addAdjustmentListener(
        new AdjustmentListener() {
          public void adjustmentValueChanged(AdjustmentEvent e) {
            g = e.getValue();
            lGreen.setText("Gruen: " + g);
            pane.setBackground(new Color(r, g, b));
          }
        }
      );

      pane.add(sGreen);


      lBlue = new Label("Rot: 0");
      lBlue.setBackground(Color.blue);
      pane.add(lBlue);

      sBlue = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 256);
      sBlue.addAdjustmentListener(
        new AdjustmentListener() {
          public void adjustmentValueChanged(AdjustmentEvent e) {
            b = e.getValue();
            lBlue.setText("Blau: " + b);
            pane.setBackground(new Color(r, g, b));
          }
        }
      );

      pane.add(sBlue);


      // define the quit button
      JButton q = new JButton("Quit");
      q.addActionListener(this);

      // add the quit button
      pane.add(q) ;

      f.setSize(150, 100);
      f.setVisible(true);
    }

    // class defines reaction to button click itself (implements ActionListener)
    public void actionPerformed(java.awt.event.ActionEvent e) {
        System.out.println("Ciao!");
        System.exit(0);
    }

    public static void main(String[] args)
    {
      FarbSlider sl=new FarbSlider();  // create object, will create a window in its constructor
    }
}