import javax.swing.border.*;

static <A extends JComponent> A addInnerMargin(final int top, final int left, final int bottom, final int right, final A c) {
  if (c != null) swing {
    Border margin = BorderFactory.createEmptyBorder(top, left, bottom, right);
    c.setBorder(jCompoundBorder(margin, c.getBorder()));
  }
  ret c;
}

static <A extends JComponent> A addInnerMargin(int w, A c) {
  ret addInnerMargin(w, w, w, w, c);
}

static <A extends JComponent> A addInnerMargin(int w, int h, A c) {
  ret addInnerMargin(h, w, h, w, c);
}