What we're going to do is convert AddressMain, which is currently a form, into an applet. Later we'll make changes to AddressModel so that it can deal with URLs instead of files. This means that it will be able to read and write to any files to which it refers, including any file transmitted over the HTTP protocol.
First let's make it so AddressMain derives from an applet instead of a frame.
Now let's add the __init__ and __destroy__ methods. __init__ gives us access to the database, which we need to initialize AddressModel. __destroy__ calls AddressModel's writeAddress() function, which writes addresses out to a file (if the protocol ...