Week 8: Oct 15

TechSupport: String.split() and what is really going on


	Searching an array A for number x:
	
	i = 0;
	while (i<A.length) {
	    if (A[i]==x) return i;
	    i++;
	}
	
	break version:
	i = 0;
	while (i<A.length) {
	    if (A[i]==x) break;
	    i++;
	}
	if (i<A.length) {
		System.out.println("value found at i=" + i);
	}

	
	Searching an ArrayList<String> A for string s:
	i = 0;
	while (i<A.size()) {
	    if (A.get(i).equals(s)) return i;
	    i++;
	}
	
	Getting "return" out of the loop body:
	
	i=0;
	while (i<A.length && A[i]!= x)
		i++
	return i;
	
	Do same for ArrayList of strings and contains instead of equals
	
	use of break
	
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What is going on in chapter 5?
* Analysis of sentences (superficial)
* Containers: HashMap and HashSet. Do we need the latter?
* String operations: trim, beginsWith, split, where to look
* Using class documentation to look stuff up
* Control flow
	1st set of keywords, then 2nd set
		(incorrect version?)
	1st keyword match (ArrayList) v any keyword match (HashSet)

What would it take to have a set of responses for each keyword,
and to pick different ones at random?
	bug[1]	-> all software has bugs
	bug[2]	-> that's not a bug, it's a feature!
	bug[3]	-> have you filed a bug report about that?
	
What would it take to match two-word pairs, in order?
	(what,best) represents "what is the best way to ..."
	(what,wrong) represents "what is wrong with you?"
	(what,do)    represents "what do I do now"

Using docs to find the String methods we need.
	* skip leading spaces
	* just check for match with "bye"
	* ignore case

Details of HashMap class, and its methods put(k,v) and get(k)
	MapTester demo
	go through demo
	use Inspector to find the collision!
	do examples on page (2nd ed: 131): how interface works
	use javadocs
	

Logic of trying group1 words before group2 (question) words
More elaborate logic for multiple tests

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Quick demo of balls

	private static final int gravity = 3;

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Wed, Oct 17

Chapter 6: Testing

Diary example: overview

concept of "Regression Testing": apply old test to each new version

Test program

Problem: how do we interpret the results??

JUnit testing: 

Create a new test in a copy of the Diary v2 example
have it create a day, and two new appointments, and test some things

JUnit testing doesn't work as well for simulating interactive input!

Skip the calculator for now

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Fri, Oct 19

How to test generateResponse(ArrayList<String> sentence)??
1. sometimes you *do* have to write manual test code. BlueJ adds the Object Bench,
but some objects (like ArrayLists) can't be created there.
2. Write (in the responseTest test class) a method testSentence() 
that returns a sentence.
Then, using the test-recording feature of bluej, run a test on generateResponse()
and as parameter supply responseTest.testSentence();
3. JUnit supports the concept of a "Fixture"; a set of objects needed for tests.
4. Even if manual creation is necessary, automated run & interpret are still powerful.


	MAYBE:
	Take a quick look at finding problems with bricks example.
	Tools:
		inspector
		println (and if(DEBUG) {...})
		debugger
		walkthroughs (manual)

		Testing:
		manual tests
		test methods
		JUnit testing


	Bricks test:
	check height, weight for 1 brick, 10 bricks
	0 bricks?	problem with height!

	Weight: 3 kg/brick

	BASE_WEIGHT not included??

	Is weight of a brick even right?

	Use DEBUGGER to find problem with height: put a breakpoint at height method

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Chapter 7: 

World of Zuul

	Code duplication: avoid
	Coupling: minimize ("loose coupling")
	Responsibility-driven design
	localizing change
	cohesion
	
	refactoring
	
Why do we care about these principles?


Demo of Zuul

Bad version of Zuul, then good version. Discuss differences.

Goals: Loose COUPLING

	COHESION: a class should represent one thing;
		each method should do one thing
		
		non-cohesive: Iterator.next() returns current item & moves on.
			but this is probably ok
			
Zuul-bad problems:
	1. Public data fields in Room: VERY bad coupling
	2. poor cohesion in goRoom(), printWelcome()
	3. Code duplication in goRoom(), printWelcome()!!!
	
	End of class: fixed #1 by adding an accessor getNorth(), 
	and making northRoom private, but that still leaves us 
	a mess when it comes time to adding new directions
	
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