Classes and Objects

Question 1

What is an object?

Answer 1

An object is any entity with the problem domain, which is recognised by the system by storing information about it and or interacting with it.

Question 2

What is the difference between a class and an object?

Answer 2

A class is a term for an object type, a template for producing instances of classes, which are called objects.

Question 3

Name 4 methods of finding classes and objects

Answer 3

Textual analysis
identifying uses
identifying players
identifying generalisation
identifying analogies
identifying re-use.

Question 4

3 different class stereotypes

Answer 4

Entity
Boundary
Control

Question 5

What is an Entity Class?

Answer 5

An entity class models the information and associated behaviour of something that is relevant to the problem domain

Question 6

What is a Control Class?

Answer 6

A class for co-ordination, sequencing and control of objects. It is recommended that there is a control class for each use case

Question 7

Boundary Class

Answer 7

Models the interaction between the actors and the system in the form of the user interface.

Question 8

How is a UML object made up?

Answer 8

Object name
Attributes
Operations

Question 9

3 types of links for a class diagram

Answer 9

Whole-part
Gen-spec
Association

Question 10

c) How would you check that your class diagram is correct?

Answer 10

1. Check that it copes with all functionality stated in the detailed use case descriptions, both in terms of objects and attributes directly identified and other attributes needed for functions to perform (e.g. status checks, indicators etc)
2. Check with senior analyst and/or colleague.
3. Possible check with User but these diagrams are not quite so easy to explain to a User.