CSC223, Class 28: Discussion of In-Class Exam 1

Admin:
* Late: Luis, Kat
* Missing: Ryan, Chase
* Whee!  We have prospective applicants (or we should).
* Warning! I will have limited email access this weekend.
* Exam due Monday.
* Read more of _Design Patterns_ :-)
* HAPPY BELATED BIRTHDAY RYAN!

Overview:
* Discussion of In-Class 1
  * General
  * Problem 1: UML
  * Problem 2: Introspection
  * Problem 4: Testing
* Questions on Take-Home 1
  * Problem 1: UML and Java Collections Framework
  * Problem 2: Introspective Testing
  * Problem 3: Building Factories
  * Problem 4: Anonymous Inner Classes
* Leftover stuff from Wednesday

General Issues on In-Class Exam
* YOU NEED TO READ INSTRUCTIONS!
  * Name on every page
  * Sign AND DATE the honesty statement
* How will I balance the two grades?
  * 2/3 better 
  * 1/3 worse
* Can I challenge grades?
  * Certainly, but I have been known to find new errors
  * I HATE "You took off X for me and Y for him/her!"

Problem One: UML

Problem Two: Introspection

* Expected
  * Good definition
  * Enough code that someone else could write their own
* Got
  * Strange definitions
    * Introspection is "run time type determination"
    * Introspection involves building new methods
  * Little code
* Good definition: Like the literal meaning: Look inside itself
  * Idea that you can determine aspects of a class *and use those aspects* at run time
* How?
  (1) Get the class of the object
  	Class c = *object*.getClass();
	Class c = Class.forName(String *name*);
	Class c = Integer.TYPE; // Boolean.TYPE, Float.TYPE, ...
  (2) Find a method associated with that class
  	Method[] methods = getMethods();
	Method[] mymethods = getDeclaredMethods();
	Method m = getMethod(String name, Class[] paramtypes)
		I want the compareTo(Vec2D) method
		Method comp = c.getMethod("compareTo", 
  	Constructor[] conses = getConstructors();
	Constructor[] conses = getDeclaredConstructors();
	Constructor cons  = getCOnsturctor(Class[] paramtypes)
						new Class[] { Class.forName("rebelsky.exam1.Vec2D") });
		Class.forName("java.lang.String")
  (3) Call that method
  	m.invoke(Object base, Object[] params)
	cons.

What if I want to call methods that start only with "test"

	Method[] mymethods = c.getDeclaredMethods();
	for (int i = 0; i < mymethods.length; i++) {
		Method m = mymethods[i];
		if (m.getName().subString(0,4).equals("test")) {
			...
		}

Problem Three: Good!

* Some of you "pushed the envelope" in the comparisons

(4) Testing!

* NO SIMPLISTIC TESTS!
* Expected:
  * A series of different tests
    * Different size arrays
    * Already ordered
    * Completely reverse ordered
    * Randomly generated
    * Duplicate elements
  * Real verification of postconditions
    * The result must be in order
    * The result must be a permutation

Questions on the Take-Home Exam?
* Problem 1: UML and Java Collections Framework
  * One diagram suffices
* Problem 2: Introspective Testing
  * 
* Problem 3: Refactoring
  * Do we have to provide *all* the code?
    * It would be nice.
    * I will survive with partial code that reveals the key ideas.
  * Do we have to provide definitions?
    * No, but it might be nice.
* Problem 4: Building Factories