code: public void fillRoundRect(final Rectangle2D pRectangle, int pArcW, int pArcH, Pattern pPattern) {
          fillShape(toRoundRect(pRectangle, pArcW, pArcH), pPattern);
      }
docs: FillRoundRect(r,int,int,pat) // fills a rectangle's interior with any pattern you
  specify. The procedure transfers the pattern with the patCopy pattern
  mode, which directly copies your requested pattern into the shape.
  
  @param pRectangle the rectangle to fill
  @param pArcW      width of the oval defining the rounded corner.
  @param pArcH      height of the oval defining the rounded corner.
  @param pPattern   the pattern to use