JSliderでクリックした位置にノブをスライド

slider.setUI(new MetalSliderUI() {
  @Override protected TrackListener createTrackListener(JSlider slider) {
    return new TrackListener() {
      @Override public void mousePressed(MouseEvent e) {
        if (UIManager.getBoolean("Slider.onlyLeftMouseButtonDrag")
              && SwingUtilities.isLeftMouseButton(e)) {
          JSlider slider = (JSlider) e.getComponent();
          switch (slider.getOrientation()) {
          case SwingConstants.VERTICAL:
            slider.setValue(valueForYPosition(e.getY()));
            break;
          case SwingConstants.HORIZONTAL:
            slider.setValue(valueForXPosition(e.getX()));
            break;
          default:
            throw new IllegalArgumentException(
                "orientation must be one of: VERTICAL, HORIZONTAL");
          }
          super.mousePressed(e); //isDragging = true;
          super.mouseDragged(e);
        } else {
          super.mousePressed(e);
        }
      }

      @Override public boolean shouldScroll(int direction) {
        return false;
      }
    };
  }
});