Swing/LineFocusTable のバックアップ(No.16)

enum Type { START, END; }

class DotBorder extends EmptyBorder {
  private static final BasicStroke DASHED = new BasicStroke(
      1f, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER,
      10f, new float[] {1f}, 0f);
  private static final Color DOT_COLOR = new Color(200, 150, 150);
  public final Set<Type> type = EnumSet.noneOf(Type.class);

  protected DotBorder(int top, int left, int bottom, int right) {
    super(top, left, bottom, right);
  }
  @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.create();
    g2.translate(x, y);
    g2.setPaint(DOT_COLOR);
    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.dispose();
  }
}