Update graphics in applet

hi,

I have an panel in my applet that draw shapes on it.
In my panel (a class that extends JPanel) I have some draw functions:

class x extends JPanel{

public void draw_function1(Graphics g){..}
public void draw_function2(Graphics g){..}
public void draw_function3(Graphics g){..}
...
}

My panel does not update graphics when I minimize the window or anything that requires refresh.
I CAN'T insert all my functions inside paint() method because the shapes are not drawn at the same time, it depends on the user events...

how can I restore the previous graphics and draw more graphics ???

thanks.