code: public final void setBorderWidth(int unit,
                                       int size) {
          if (size < 0) {
              throw new IllegalArgumentException("Border width cannot be less than zero.");
          }
  
          int scaledSize = (int) TypedValue.applyDimension(unit, size, getResources().getDisplayMetrics());
          setBorderInternal(scaledSize, mBorderColor, true);
      }
docs: Sets the border width.
  
  @param unit The desired dimension unit.
  @param size