Week 4

Question 1

What are the advantages of object oriented design?

Answer 1

Can save effort - reuse generalised components

Can improve quality - modularity, loosely coupled subsystems

Question 2

What are the 3 components of an object?

Answer 2

State

Behaviour

Identity

Question 3

In OOP, __________ are the primary means of abstraction.

Answer 3

Objects

Question 4

What is information hiding?

Answer 4

Only an object’s Interface is visible to other objects

Question 5

Inheritance is how object oriented languages implement

Answer 5

generalisation/specialisation

Question 6

What is inheritance?

Answer 6

When the whole description of a superclass applies to all its subclasses

Question 7

‘implements’ is how java implements

Answer 7

Subtyping

Question 8

‘extends’ is how java implements

Answer 8

Subclassing

Question 9

What is the difference between subtyping and subclassing?

Answer 9

Subtypes support all the operations on the supertype

Subclassing reuse the code of the superclass and can add extra methods

Question 10

What is generalisation?

Answer 10

is-kind-of

Superclass is a generalization of subclass

e.g. Teacher is a kind of Person

Question 11

Subtyping is also known as an _______ relationship

Answer 11

is-a

Question 12

What does polymorphism allow?

Answer 12

One message to be sent to multiple objects of different classes

Question 13

What are 3 kinds of polymorphism?

Answer 13

Overloading

Dynamic Binding

Genericity

Question 14

What is overloading?

Answer 14

Method of the same name is defined for different argument types

Question 15

What is dynamic binding?

Answer 15

When a message is dispatched, the method that is invoked is chosen according to the type of the object (i.e. at runtime).

Question 16

What is genericity?

Answer 16

A mechanism allowing type-safe programming using generic classes

Question 17

Templates are a form of

Answer 17

genericity

Question 18

What is the purpose of analysis when making models?

Answer 18

Understanding the problem

Question 19

What is the purpose of design when making models?

Answer 19

Understanding the solution

Question 20

What is an analysis pattern?

Answer 20

Group of concepts representing a common construction in business modeling relevant to one or more domains

Question 21

What is a type diagram?

Answer 21

Structral view of a system

describes the types of objects and their relationships

Question 22

What notation are type diagrams based on?

Answer 22

Odell’s notation

NOT UML

Question 23

What is a complete partition, in type diagrams?

Answer 23

all instances of supertype must be instances of either subtype

Question 24

What is an incomplete partition in type diagrams?

Answer 24

instances of supertype can be instances of either subtype or neither

Question 25

When multiple attributes interact with behaviour that might be used in several types, you should

Answer 25

combine the attributes into a new fundamental type