L' Mathiassen, A' MunkMadsen, P' A' Nielsen

1
Problem-Domain Analysis Classes

• Overview, Principles Techniques
• Part II Chapter 3

2
Results
Customer
name
Account opened
address
(date)
1
balance
Customer
Account closed
(date)
Open
0..

0..

Appointment
1
Amount withdrawn
Amount deposited
1
(date, amount)
(date, amount)
1
1..

Day Schedule
Employee
1
1..

Apprentice
Assistant
Time Period
1
Other
Free
Work
3
Analysis of the problem domain

• Problem domain That part of a context that is
  administrated, monitored, or controlled by a
  system

4
Activities
Class Structure Behavior
5
Overview of Problem Domain
6
Results of Classes

• Event table
• Shows selected classes and events

reserved cancel treated employed resigned grad. a
greed Customer ü ü ü Assistant ü ü ü ü
ü Apprentice ü ü ü ü Appointment ü
ü ü Plan ü ü
7
Classify objects and events in the problem domain
Contract

Contract signed
Released

Abstraction Classification
8
What is an object?

• ObjectAn entity with identity, state, and
  behavior
• Class A description of a collection of objects
  sharing structure, behavioral pattern, and
  attributes.

9
What is an event?

• EventAn instantaneous incident involving one or
  more objects.
• Atomic
• Common to several objects
• Unique name

10
Activities in Class
Find candidates
Find candidates
for classes
for events
Evaluate and select
systematically
Systems definition
Event table
11
Systematic Evaluation

• General evaluation criteria
• Is the class or event within the system
  definition?
• Is the class or event relevant for the
  problem-domain model?

• Criteria for classes
• Can you identify objects from the calss?
• Does the class contain unique information?
• Does the class encompass multiple objects?
• Does the class have a suitable and manageable
  number of events?
• Criteria for events
• Is the event instantaneous?
• Is the event atomic?
• Can the event be identified when it happens?

12
Overview of Class
13
Exercise

• Find candidates for classes
• Find candidates for events
• Combine classes and events in an event table
• Be precise in the argumentation about which
  classes and events that are in or out.