The switchover problem

[Roedy Green]

I have an Applet that uses serialized objects.

Let's say I decide to change the format of the serialized objects.

I create new *.ser files and a new Applet, then upload the whole mess
to the website.

Unfortunately, for a short while during the upload there are a mix of
old and new ser files, and the wrong applet for some of them.

Further, even after everything is uploaded, it is possible some people
may have the old applet running in their browser or cached.

I wonder what sorts of technique there are for a smooth transition.

possible solutions are:

Some special sort of FTP upload that uploads files and only renames
them all at once at the end.

The Applet continually checks if it has been updated and shuts down
gracefully if it has.

 

[Carl Howells]

I have an Applet that uses serialized objects.

Let's say I decide to change the format of the serialized objects.

I create new *.ser files and a new Applet, then upload the whole mess
to the website.

Unfortunately, for a short while during the upload there are a mix of
old and new ser files, and the wrong applet for some of them.

Further, even after everything is uploaded, it is possible some people
may have the old applet running in their browser or cached.

I wonder what sorts of technique there are for a smooth transition.

The best solution is probably to not overwrite the previous Applet at
all. Instead, put it in a parallel directory, and change links to point
to it instead. Then, after sufficient time has gone by, remove the
first one.