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

/**
 * Abstract base class for all IncDec's
 * with specialized stuff factored into separate overridable methods
 */
abstract public class Incdec extends JPanel implements ActionListener {
    /**
     * Our internal components that we need to remember
     */
    protected JButton upButton, downButton;
    protected JLabel label;

    /**
     * Our data, initialized inline here 
     */
    protected int value = 0;
    protected int min = 0;
    protected int max = 100;
    protected int incr = 1;

    /**
     * Only those aspects of initialization that everbody will want
     */
    protected Incdec () {
	// Put a border on our JPanel
	// default color, user can modify later
	setBorder (new LineBorder(Color.RED, 1));
    }

    /**
     * Pieces of old constructor, factored out here for subclasses to use
     */
    protected void makeUp () { //*1 Chop up old constructor for use by subclasses
	upButton = new JButton ("+"); //*1
	upButton.addActionListener (this); //*1
	add (upButton); //*1
     }

    protected void makeDown () { //*2 makeDown, similarly
	downButton = new JButton ("-"); //*2
	downButton.addActionListener (this); //*2
	add (downButton); //*2
    }
    
    protected void makeLabel () { //*3 makeLabel, similarly
	label = new JLabel (); //*3
	label.setHorizontalAlignment (JLabel.CENTER); //*3
	refreshLabel (); //*3
	add (label); //*3
    }

    /**
     * Common callback for both buttons,
     * we use ivar to disambiguate.
     */
    public void actionPerformed (ActionEvent e) {
        if (e.getSource()==upButton) value += incr;
	else if (e.getSource()==downButton) value -= incr;

	// Clamp at bounds
	if (value > max) value = max;
	if (value < min) value = min;

	// Update our widget to match
	refreshLabel ();
    }

    /**
     * Common code fragment, extracted to here
     */
    protected void refreshLabel() {
	label.setText (String.valueOf (value));
    }

    /**
     * Just as an example, we let user customize border color here
     */
    public void setBorderColor (Color color) {
	setBorder (new LineBorder(color, 1));
    }

    public int getValue() { return value; }
}