Swing/TableScrollOnTouchScreen のバックアップ(No.3)

class TableTouchScreenHandler extends MouseAdapter implements ListSelectionListener {
  public static final int VELOCITY = 5;
  public static final int DELAY = 10;
  public static final double GRAVITY = .95;
  private final Cursor dc = Cursor.getDefaultCursor();
  private final Cursor hc = Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
  private final Timer scroller;
  private final Point startPt = new Point();
  private final Point delta = new Point();

  protected TableTouchScreenHandler(JTable table) {
    super();
    this.scroller = new Timer(DELAY, e -> {
      System.out.print(".");
      JViewport vport = (JViewport) SwingUtilities.getUnwrappedParent(table);
      Point vp = vport.getViewPosition();
      vp.translate(-delta.x, -delta.y);
      table.scrollRectToVisible(new Rectangle(vp, vport.getSize()));
      if (Math.abs(delta.x) > 0 || Math.abs(delta.y) > 0) {
        delta.setLocation((int) (delta.x * GRAVITY), (int) (delta.y * GRAVITY));
      } else {
        ((Timer) e.getSource()).stop();
      }
    });
  }

  @Override public void mousePressed(MouseEvent e) {
    System.out.println("mousePressed: " + delta);
    Component c = e.getComponent();
    c.setCursor(hc);
    // c.setEnabled(false);
    Container p = SwingUtilities.getUnwrappedParent(c);
    if (p instanceof JViewport) {
      startPt.setLocation(SwingUtilities.convertPoint(c, e.getPoint(), p));
      scroller.stop();
    }
  }

  @Override public void mouseDragged(MouseEvent e) {
    Component c = e.getComponent();
    Container p = SwingUtilities.getUnwrappedParent(c);
    if (p instanceof JViewport) {
      JViewport vport = (JViewport) p;
      Point cp = SwingUtilities.convertPoint(c, e.getPoint(), vport);
      Point vp = vport.getViewPosition();
      vp.translate(startPt.x - cp.x, startPt.y - cp.y);
      delta.setLocation(VELOCITY * (cp.x - startPt.x), VELOCITY * (cp.y - startPt.y));
      ((JComponent) c).scrollRectToVisible(new Rectangle(vp, vport.getSize()));
      startPt.setLocation(cp);
    }
  }

  @Override public void mouseReleased(MouseEvent e) {
    System.out.println("mouseReleased: " + delta);
    JTable c = (JTable) e.getComponent();
    c.setCursor(dc);
    // c.setEnabled(true);
    if (c.isEditing()) {
      delta.setLocation(0, 0);
    } else {
      scroller.start();
    }
  }

  @Override public void valueChanged(ListSelectionEvent e) {
    System.out.println("\nvalueChanged: " + e.getValueIsAdjusting());
    if (scroller.isRunning()) {
      System.out.println("isRunning");
      delta.setLocation(0, 0);
    }
    scroller.stop();
  }
}