Progressive RGB rainbow changment algorithm. (basics)

    private int r = 255; // Default color to red.
    private int g = 0;
    private int b = 0;

    private void nextRGB() {
        if (r == 255 && g < 255 && b == 0)
            g += 15;
        if (g == 255 && r > 0 && b == 0)
            r -= 15;
        if (g == 255 && b < 255 && r == 0)
            b += 15;
        if (b == 255 && g > 0 && r == 0)
            g -= 15;
        if (b == 255 && r < 255 && g == 0)
            r += 15;
        if (r == 255 && b > 0 && g == 0)
            b -= 15;
    }