Shaun Conlon
CS 211
Section 6
3/6/2003 Notes

Topics for this week:
-P1 Questions
-A4 Questions
-Event Model
-Timer

1) P1 Questions:

Questions on the prelim will be:
	1 - Short Answer
	2 - Induction
	3 - Inheritance
	4 - Recursion
	5 - Parsing
	6 - Lists
	Bonus - ???

You should make sure you understand the lecture notes and assignments, using 
the textbook to supplement any unclear material.

2) A4 Questions

You should pay close attention to the examples posted on the Assignments page.  
The Example1 and Example2 files have the basics of your animation written for 
you.  By adapting his code to the puzzle, you shouldn't have too much trouble.  
I would recommend getting the puzzle to work completely with clicking the 
pieces before you add the solve functionality.

3) Event Model

Here are some important points about the event model:

-Many, many things in a GUI will generate an event (e.g. clicking a button, 
clicking the mouse, moving the mouse, dragging the mouse, moving the window, 
resizing the window, closing the window, etc.)
-When an event occurs, Java sends information about the event to appropriate 
listeners that have already registered to receive that event
-If no listener is assigned to receive a particular event, nothing will happend 
when it occurs (e.g. nothing happens when the mouse is clicked in the 
background of your GUI because there is no listener for that event)
-When writing code, you only need to create listeners for the events that 
matter to your application

There are multiple ways to create listeners:
1) Use the GUI class itself as a listener (e.g. addActionListener(this))
2) Use another class as a listener (e.g. addActionListener(new MyListener())
3) Use an anonymous class as a listener (e.g. addActionListener(new 
ActionListener() {...)

The most popular approaches are 1 and 3, because 2 requires many other classes 
to be written for substantial GUIs.

Your listeners will usually be implementing certain interfaces from the 
java.awt.event package (e.g. ActionListener, WindowListener, etc.).  The API 
also has some classes that are designed for convenient GUI design (e.g. 
WindowAdapter).

4) Timer

Because of the way Java is implemented, you cannot have your solve method 
simply solve the puzzle completely in one pass if you want to have an interrupt 
button.  So, for the solve animation, you have to use either Timer or another 
way.

Note: you don't have to use Timer for the animation.  Using threads is also 
allowed (although Timer is probably easiest for most people).

A Timer works by sending an event to a specified listener again and again with 
a specified delay between sucessive events.  You can use this for the solve 
animation for the puzzle - you will create a timer that generates an event that 
does one move of the solution.  The interrupt button will stop your Timer.

Email me (sc235) with any questions.