Class Window can be replaced with
a subclass of Window (which will
be called Safe$Window in this demo)
that performs more security and
sanity checks. For example, Safe$Window's
setSize() method can
limit the size of a window so that the window
should be fully shown up.
Since Safe$Window is a subclass
of Window, the applet should not
notice the change, unless it attempts to create
a very large window.
The proxy server can restrict applets
without requiring any changes in
either web server or the Jave Virtual Machine
in the web browser.
*
Window size
- an applet can't create a window whose size is bigger than 700*500 in pixels
*
Window position
- every window is poped up at (0, 0) so that the status line should be shown up
*
Number of windows
- an applet can't open more than 2 windows at the same time
* Access to network resources