CSC223 2004F, Class 31: Choosing and Using Heuristics

Admin:
* Next project stage:
  * New groups
    * SamTheStickBug: SamLouisa, SamTang, SamMartin, SamChase
    * Beetle: Gene, Ryan, Omondi
    * Caterpillar: Luis, Evan, Jesse
    * Dragonfly: Merrick, Mark, Kat
  * Combine everything so far:
    * Two views
    * One model (the two-dimensional array)
    * One 'automated' controller (the bug)
  * Add: 
    * 'Random' initialization of world
    * A mechanism for telling all bugs to do something
  * Coming: 
    * Multiple hives
    * Controller UI
    * Competitions!
    * Presentations!
* Prospies!
  * From Fairfield
  * Do people regularly insult your town?
  * Tell us about the University: It's fabulously weird
* Demos!
  * Fearsomefoursome: 
    * Cats are cute.  
    * Pheremones are missing.  
    * Interesting idea: High-level view has buttons that lead to low-level views.
    * Each button is linked to a particular tile and queries that tile for the objects in that tile.  Calls createLabel or something for each object.  Labels have images.
    * Can it redraw itself when the world changes?  Yes, we think.
  * Glimmerers + 1
    * No pheremones!
    * Scales nicely
      * Figures out a percentage of the width and height
    * Show location with setToolTipText (or something similar)
    * Menus!
    * Can we show a portion of the world that doesn't start at 0,0?
    * icons drawn with drawImage with width and height
* Monday: Exams returned and discussed
* Next two weeks: Design Patterns

Overview:
* Why read Riel, revisited
* How today's class works
* Choosing a relationship
* Choosing how to get objects to use

/Why are we reading Riel: Design Heuristics/

* Tells us lots of things we should do that are helpful (the heuristics)
* The book claims to tell us how to design software, and this course is titled "Software Design"
* Helps us make decisions as we design software
* Reminds you of questions to ask (even if they're not expressed as heuristics)
  * E.g., "There are five ways you can obtain an object to use"; but "Sorry, I'm not giving you any heuristics about that"
* Reveals some of the issues Object-Oriented Programmers think about
  * See the OOP Umwelt: "Kindof enviroment" "World View"
  * Example: Use polymorphism instead of "explicit case analysis"

/Wednesday/

* The ways in which an object obtains other objects to use
  * Passed as a parameter to a method call
  * Contain that object
  * Contain a reference to that object
  * Create the object ("rich person's solution")
  * Ask an oracle for the object
  * Use a global object
  * Pass the request to an oracle for forwarding

HOW DO WE MAKE THE CHOICE OF WHICH WAY SAM GETS A PEN?
* First answer: Heuristics
* Kat's first heuristic: If the object is used in only one method, you should either (1) receive it as a parameter or (2) create it yourself

* The ways in which classes and objects relate
  * Use
  * Contain
    * Directly
    * Via association
  * Extend
  * Associate
    * Contain
    * Create
    * Other (default)

ASSIGNMENT FOR MONDAY!  Decide which heuristics help us make those decisions