private static boolean isCellEmpty(final DimensionInfo info, final int cellIndex) {
    if (cellIndex < 0 || cellIndex >= info.getCellCount()) {
      throw new IllegalArgumentException("wrong cellIndex: " + cellIndex + "; cellCount=" + info.getCellCount());
    }
    for (int i = 0; i < info.getComponentCount(); i++) {
      final Component component = info.getComponent(i);
      if (info.getCell(i) == cellIndex && !(component instanceof Spacer)) {
        return false;
      }
    }
    return true;
  }
private static boolean isCellEmpty(final DimensionInfo info, final int cellIndex)