Swing/DifferentCellHeight のバックアップ(No.17)

class TextAreaRenderer extends JTextArea implements ListCellRenderer<String> {
  private Border focusBorder;
  private static final Border NOMAL_BORDER =
    BorderFactory.createEmptyBorder(2, 2, 2, 2);
  private static final Color EVEN_COLOR = new Color(230, 255, 230);
  @Override public Component getListCellRendererComponent(
      JList list, String str, int index,
      boolean isSelected, boolean cellHasFocus) {
    //setLineWrap(true);
    setText(Objects.toString(str, ""));
    if (isSelected) {
      setBackground(list.getSelectionBackground());
      setForeground(list.getSelectionForeground());
    } else {
      setBackground(index % 2 == 0 ? EVEN_COLOR : list.getBackground());
      setForeground(list.getForeground());
    }
    if (cellHasFocus) {
      if (focusBorder == null) {
        focusBorder = new DotBorder(
            new Color(~list.getSelectionBackground().getRGB()), 2);
      }
      setBorder(focusBorder);
    } else {
      setBorder(NOMAL_BORDER);
    }
    return this;
  }
}

private DefaultListModel makeList() {
  DefaultListModel model = new DefaultListModel();
  model.addElement("一行");
  model.addElement("一行目\n二行目");
  model.addElement("一行目\n二行目\n三行目");
  model.addElement("四行\n以上ある\nテキスト\nの場合");
  return model;
}