The recent set of posts that allow people reading this blog to make persistent changes to my Java applets is making use of a capability provided by Murphy Stein — a Ph.D. student in the NYU Department of Computer Science.
Murphy wrote two computer programs that are sitting on my web-site (commonly referred to as the server side):
- a program that waits until a Java applet sends it some data, and then writes that data to a file on the web-site’s host computer;
- a program that waits until a Java applet asks for some data, and then retrieves the data from that same file.
It’s not very fancy, but it completely gets the job done. Basically, this allows each Java applet to keep its very own persistent record of what’s going on — like having your own locker at the gym.
Of course every Java applet uses its locker differently. Some might store little bits of text, while others store instructions about how to draw a picture.
But what they all have in common is that they allow people to make changes that will be remembered when somebody else visits the site. Which is very cool!