Interfaces, GUIs, and Applets

CS 161 - Java

A Typical Event Driven Application

Somewhere inside most modern applications that use a graphical user interface (and in many other types of applications using the Event Driven model) is what amounts to an infinite loop.

The infinite loop may be hidden away inside an application framework you are using.

Whether hidden or not, those infinite loops look something like the following pseudo code:

while (true) {

  event = waitForSomethingInterestingToHappen();

  callThingThatRegisteredInterest( event );

}

Event Driven Programming is all about writing the methods that are the thingThatRegisteredInterest in handling some event, e.g.,

methods to call when Buttons are clicked on
methods to call when Menu items are selected
Text display that allows you to type, delete, cut, paste, ...
(Actor, Plane, Ship, Car) that gets 'hit', shot, attacked, ...

Question: How is event driven programming different from what we've done so far?

jwd