/*
 * JScrollBar.java
 *
 * Created on October 20, 2001, 10:18 PM
 */

package com.shadowcraft.util;

import java.awt.*;
import java.awt.event.*;

/**
 * JScrollBar which auto-scrolls only if it's already positioned at its maximum
 * position.
 * @author Gili Tzabari
 */
public class JAutoScrollBar extends javax.swing.JScrollBar
{ 
  /**
   * Maximum value of JScrollBar during last call to adjustmentValueChanged().
   */
  protected int oldMax=0;
  
  public JAutoScrollBar()
  {
    super();
    init();
  }
  
  public JAutoScrollBar(int orientation)
  {
    super(orientation);
    init();
  }
  
  public JAutoScrollBar(int orientation, int value, int extent, int min, int max)
  {
    super(orientation, value, extent, min, max);
    init();
  }

  public void init()
  {
    addAdjustmentListener(new AdjustmentListener()
    {
      public void adjustmentValueChanged(AdjustmentEvent e)
      {        
        Adjustable source = (Adjustable) e.getSource();
        if (source.getValue()+source.getVisibleAmount() == oldMax && source.getMaximum() > oldMax)       
          source.setValue(source.getMaximum());
        oldMax = source.getMaximum();
      }
    });
  }
}