Lecture 12

Question 1

Which two types of quality are there?

Answer 1

internal quality and external quality

Question 2

What is external quality?

Answer 2

The user experience, quality from the perspective of the user

Question 3

Which two things influence external quality the most?

Answer 3

No crashes, good performance

Question 4

What is internal quality

Answer 4

The quality from the developer perspective

Question 5

Which three things influence internal quality the most?

Answer 5

How understandable the code is, if the code is easy to change and whether the code is testable.

Question 6

What are 6 basic rules for having high quality code?

Answer 6

1. LOC per method rule
2. Duplicated code rule
3. CC rule
4. Rule of parameter list length
5. Code Style rule
6. Testing rule

Question 7

What is the LOC per method rule?

Answer 7

The LOC per method rule is that a method should never have more than 40 lines of code, and that if a code has more than 20 lines of code you should review it and consider to change the method. (THESE NUMBERS ARE JAVA)

Question 8

What is the duplicated code rule?

Answer 8

Never duplicate code, if you need code twice, put it in a method that you can call from multiple places.

Question 9

What does CC in the CC rule stand for?

Answer 9

Cyclomatic Complexity

Question 10

How do you calculate the CC of a piece of code?

Answer 10

Counting all conditions and adding 1 (conditions: if, while, for et.c).

Question 11

What is the CC rule

Answer 11

the rule that a method should not have a Cyclomatic complexity higher than 10, if it is above 5 you should review the method and consider changing it / splitting it up.

Question 12

What is the rule of parameter list length

Answer 12

The rule that a method should in general not have more parameters than 4.

Question 13

What is the code style rule?

Answer 13

The code style rule states that you should follow code conventions

Question 14

What are the 4 conventions of the code style rule?

Answer 14

indentation, whitespace, naming, documentation

Question 15

What is the test rule?

Answer 15

The test rule states that the amount of unit tests you have for a method should be greater than or equal to the CC of the method.

Question 16

How do you call the things that split tokens in a inputStream / string

Answer 16

delimiters

Question 17

What is autoboxing?

Answer 17

Autoboxing is when a primitive data type is changed into a reference data type, because this is necessary for e.g. generics.

Question 18

What are generics?

Answer 18

Generics are things that the Java compiler sees as “objects” and for which instances of multiple classes can be used.

Question 19

What are wrapper classes? Give an example of a wrapper class

Answer 19

Wrapper classes are classes that function like the primitive types, but are reference data types. e.g. Integer, Character

Question 20

Why would you use generics?

Answer 20

To create methods or classes that work with different types of objects (e.g. a NumberList with methods that work both for integers and floating-point number)

Question 21

How can we use generics?

Answer 21

By using (less-than-bracket) and (greater-than-bracket) in either a class signature or a method signature to specify that we are using generics.

Question 22

Can we specify generics? How?

Answer 22

Yes, we can specify generics so that only instances of certain classes, and not all classes are excepted. We can do this by adding extends InsertHere to the generic in the signature.