Drawing a line with arrow in Java

Can anyone guide me how to code the arrow line in different direction. wa and wl is positive the rectangle will be on top of the x-axis. Below example shown if wl is negative and wa is positive. The code below shown how i code the rectangle shape. x1 is the varaible to state where to start at x axis. e1 is the length of the shape, wa1 and wl1 is the height. wsign to determine the height wa1 or wl1 should display at negative side or positive side.

        if (Math.abs(wl1) > Math.abs(wa1)) {
            y_scale = (load_y0 - 40) / (double) Math.abs(wl1);
        } else {
            y_scale = (load_y0 - 40) / (double) Math.abs(wa1);
        }
        g.drawLine((int) ((double) x0 + x1 * x_scale), (int) (load_y),
                    (int) ((double) x0 + x1 * x_scale),
                    (int) (load_y + (wa1 * y_scale) * -1));
            g.drawLine((int) ((double) x0 + (x1 + e1) * x_scale),
                    (int) (load_y), (int) ((double) x0 + (x1 + e1)
                            * x_scale), (int) (load_y + (wl1 * y_scale)
                            * -1));

            g.drawLine((int) ((double) x0 + x1 * x_scale),
                    (int) (load_y + (wa1 * y_scale * -1)),
                    (int) ((double) x0 + (x1 + e1) * x_scale),
                    (int) (load_y + (wl1 * y_scale) * -1));