JSpinField.java

package core.datechooser;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class JSpinField extends JPanel
implements CaretListener, AdjustmentListener, ActionListener
{
/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
/**
 * Default JSpinField constructor.
 */
public JSpinField()
{
   super();
   min   = 0;
   max   = 100;
   value = 0;
   darkGreen = new Color( 0, 150, 0 );

   setLayout( new BorderLayout() );
   textField = new JTextField( Integer.toString(value) );
   textField.addCaretListener( this );
   textField.addActionListener( this );
   add( textField, BorderLayout.CENTER );
   scrollBar = new JScrollBar(Adjustable.VERTICAL, 0, 0, 0, 100);
   scrollBar.setPreferredSize( new Dimension ( scrollBar.getPreferredSize().width,
						  textField.getPreferredSize().height ) );
   scrollBar.setMinimum( min );
   scrollBar.setMaximum( max );
   scrollBar.setValue( max + min - value );
   scrollBar.setVisibleAmount( 0 );

   scrollBar.addAdjustmentListener( this );
   add( scrollBar, BorderLayout.EAST );
}

protected void setValue( int newValue, boolean updateTextField, boolean updateScrollbar )
{
   int oldValue = value;

   if( newValue < min )
	 value = min;
   else if( newValue > max )
	 value = max;
   else
	 value = newValue;

   if( updateTextField )
   {
	 textField.setText( Integer.toString( value ) );
	 textField.setForeground( Color.black );
   }

   if( updateScrollbar )
	 scrollBar.setValue( max + min - value );

   firePropertyChange( "value", oldValue, value );
}

/**
 * Sets the value.
 * This is a bound property.
 *
 * @see #getValue
 * @param newValue the new value
 */
public void setValue( int newValue )
{
   setValue( newValue, true, true );
}

/**
 * Returns the value.
 */
public int getValue()
{
   return value;
}

/**
 * Sets the minimum value.
 *
 * @see #getMinimum
 * @param newMinimum the new minimum value
 */
public void setMinimum( int newMinimum )
{
   min = newMinimum;
   scrollBar.setMinimum( min );
}

/**
 * Returns the minimum value.
 */
public int getMinimum()
{
   return min;
}

/**
 * Sets the maximum value.
 *
 * @see #getMaximum
 * @param newMaximum the new maximum value
 */
public void setMaximum( int newMaximum )
{
   max = newMaximum;
   scrollBar.setMaximum( max );
}

/**
 * Returns the maximum value.
 */
public int getMaximum()
{
   return max;
}

/**
 * Sets the font property.
 *
 * @param font the new font
 */
public void setFont( Font font )
{
   if( textField != null )
	 textField.setFont( font );
}

/**
 * Sets the foreground color.
 *
 * @param fg the new foreground
 */
public void setForeground( Color fg)
{
   if( textField != null )
	 textField.setForeground( fg);
}

/**
 * After any user input, the value of the textfield is proofed. Depending
 * on being an integer, the value is colored green or red.
 */
public void caretUpdate( CaretEvent e )
{
   try
   {
	 int testValue = Integer.valueOf( textField.getText() ).intValue();

	 if( (testValue >= min ) && ( testValue <= max ) )
	 {
	    textField.setForeground( darkGreen );
         setValue(testValue, false, false);
	 }
	 else
	 {
	    textField.setForeground( Color.red );
	 }
   }
   catch( Exception ex )
   {
	 if( ex instanceof NumberFormatException )
	    textField.setForeground( Color.red );

	 // Ignore all other exceptions, e.g. illegal state exception
   }
   textField.repaint();
}

/**
 * The 2 buttons are implemented with a JScrollBar.
 */
public void adjustmentValueChanged( AdjustmentEvent e )
{
   setValue( max + min - e.getValue(), true, false );
}

/**
 * After any user input, the value of the textfield is proofed. Depending
 * on being an integer, the value is colored green or red. If the textfield is
 * green, the enter key is accepted and the new value is set.
 */
public void actionPerformed( ActionEvent e )
{
   if( textField.getForeground().equals( darkGreen ) )
	 setValue( Integer.valueOf( textField.getText() ).intValue() );
}

/**
 * Creates a JFrame with a JSpinField inside and can be used for testing.
 */
static public void main( String[] s )
{
   JFrame frame = new JFrame( "JSpinField" );
   frame.getContentPane().add( new JSpinField() );
   frame.pack();
   frame.setVisible( true );
}

private JTextField textField;
private JScrollBar scrollBar;
private Color      darkGreen;
private int        min;
private int        max;
private int        value;
}