Swing/LineFocusTable のバックアップ(No.13)

class DotBorder extends EmptyBorder {
  public enum Type { START, END; }
  private static final BasicStroke dashed = new BasicStroke(
    1f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER,
    10f, (new float[] {1f}), 0f);
  private static final Color dotColor = new Color(200, 150, 150);
  public DotBorder(int top, int left, int bottom, int right) {
    super(top, left, bottom, right);
  }
  public EnumSet<Type> type = EnumSet.noneOf(Type.class);
  @Override public boolean isBorderOpaque() {
    return true;
  }
  @Override public void paintBorder(
        Component c, Graphics g, int x, int y, int w, int h) {
    Graphics2D g2 = (Graphics2D) g;
    g2.translate(x, y);
    g2.setPaint(dotColor);
    g2.setStroke(dashed);
    if (type.contains(Type.START)) {
      g2.drawLine(0, 0, 0, h);
    }
    if (type.contains(Type.END)) {
      g2.drawLine(w - 1, 0, w - 1, h);
    }
    if (c.getBounds().x % 2 == 0) {
      g2.drawLine(0, 0, w, 0);
      g2.drawLine(0, h - 1, w, h - 1);
    } else {
      g2.drawLine(1, 0, w, 0);
      g2.drawLine(1, h - 1, w, h - 1);
    }
    g2.translate(-x, -y);
  }
}