Swing/RollOverListener のバックアップ(No.9)

class RollOverList extends JList {
  private int rollOverRowIndex = -1;
  public RollOverList() {
    super();
    RollOverListener rol = new RollOverListener();
    addMouseMotionListener(rol);
    addMouseListener(rol);
    setCellRenderer(new RollOverCellRenderer());
  }
  private class RollOverCellRenderer extends DefaultListCellRenderer{
    @Override public Component getListCellRendererComponent(
            JList list, Object value, int index,
            boolean isSelected, boolean cellHasFocus) {
      Component c = super.getListCellRendererComponent(
          list, value, index, isSelected, cellHasFocus);
      if(index == rollOverRowIndex) {
        c.setBackground(new Color(220,240,255));
        if(isSelected) c.setForeground(Color.BLACK);
      }
      return c;
    }
  }
  private class RollOverListener extends MouseInputAdapter {
    @Override public void mouseExited(MouseEvent e) {
      rollOverRowIndex = -1;
      repaint();
    }
    @Override public void mouseMoved(MouseEvent e) {
      int row = locationToIndex(e.getPoint());
      if(row != rollOverRowIndex) {
        rollOverRowIndex = row;
        repaint();
      }
    }
  }
}