Objects and their Associations

1
Objects and their Associations

• Studio Design in HCI
• Cheryl Geisler
• Lecture 13

2
Agenda

• Schedule Adjustments
• Objects Their Associations
• Modelling Problem
• Defining Views

3
Schedule Adjustments
4
Lecture shifts

• Thanks!
• Last week Lecture 11/12 cancelled
• This week become Lecture 13 14
• and so on

5
Assignment shifts

• This week Modelling Home and modelling
  consultation cancelled
• Two weeks (after break) Modelling homework and
  consultations due

6
Work (Phase II) Extends

• March 15 lectures
• March 21 homework (break)
• March 28 lectures
• April 5 presentations
• April 11 memos

7
Work (Phase III) Contracts

• April 12 Lectures
• April 20 Paper Prototype
• April 27 Implementation Preview
• May 3 Presentations
• May 9 memos
• May 10 Final Individual Assessment

8
Conceptual DesignGetting Oriented
9
Deliverables

• An conceptual model of the activity transformed
  by the HCI Design including
• a transformed scenario
• 3-5 key views
• 3-5 key interactions,
• state tables for 3-5 principal objects

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Organization of the Deliverables
Interaction Diagrams
State Tables
Class Diagrams (Views)
Transformed Scenariao
11
This Lecture Class Diagram

• v shows the objects in the HCI
• v shows the associations among them

12
Next Lecture Views

• v Places them in the context of users views

13
Class Diagrams
14
Sample Class Diagram
dates
room type
15
Hotel has rooms
dates
room type
16
Guest stay in rooms
dates
room type
17
Guests plan to stay in hotel through reservations
Reservation
0..
dates
plan to stay
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
18
Functions of a Class Diagram

• Conceptualized the objects the user will work
  with
• Places the user in the context of the new HCI
• Identifies the key actions/associations with
  those objects
• Represents the mediational means in the
  transformed activity

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Conceptualized the objects the user will work
with
Reservation
0..
dates
plan to stay
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
20
Places the user in the context of the new HCI
Reservation
0..
dates
plan to stay
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
21
Identifies the key actions/associations with
those objects
Reservation
0..
plan to stay
dates
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
22
Represents the mediational means in the
transformed activity
Reservation
0..
dates
plan to stay
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
23
This Lectures Goal

• Understand class diagrams
• Introduce tools of construction
• For further review
• http//www-3.ibm.com/ibm/easy/eou_ext.nsf/Publish/
  589

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Basics of Class Diagrams
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Class Diagram of Making a Reservation
Reservation
0..
plan to stay
dates
room type
0..
Hotel
Guest
1
n
0..
Room
stay
0..
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A Word about Notation

• Unified Modeling Language (UML)
• Simplified

Room
27
Basics of a Class Diagram

• Objects
• hotel
• guest

0..
plan to stay
0..
Hotel
Guest
28
Basics of a Class Diagram

• Associations
• plan to stay

0..
plan to stay
0..
Hotel
Guest
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Basics of a Class Diagram

• Cardinality
• many-to-many

0..
plan to stay
0..
Hotel
Guest
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Basics of a Class Diagram

• Cardinality
• one-to-one

Guest
0..
Room
stay
1
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Basics of a Class Diagram

• Association Objects Reservation
• Record details of many-to-many relationships

Reservation
dates
0..
plan to stay
room type
0..
Hotel
Guest
32
Association Types
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1. Basic Association

• labeled association

Guest
0..
Room
stay
0..
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2. Has a Association

• has a association
• A Hotel has n Rooms.
• Line
• Diamond
• Directional arrow

Hotel
1
n
Room
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Has a vs Basic Association

• has a
• is a special kind of
• basic association

Hotel
1..
has
0..
Room
36
3. Informational Association

• Showing needed state information
• Hotel has n Rooms which may be free or occupied

Hotel
1
free
occupied
n
Room
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4. Subclass Association

• Showing distinct types of objects within a given
  class

Room
Occupied Room
Free Room
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Subclass vs Informational

• free as information state
• vs single as subclass

Hotel
1
free
occupied
n
Room
39
5. Coexisting Associations

• The association stay between guest and room

Guest
0..
Room
stay
0..
Stay
40
coexists with
Hotel

• the association occupied between hotel and
  occupied room

1
occupied
n
Room
Room
Occupied Room
41
Coexisting Association
Hotel
1
occupied
n
Room
Guest
0..
Occupied Room
0..
stay
Stay
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Identifying Associations
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Which association? The datebook schedules events
Date Book
Event
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Basic AssociationDate Book schedules Events
Event
1
0..
Date Book
schedules
45
Which association? A time may be either an
available time or a scheduled time
Time
Scheduled Time
Available Time
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Subclass Association A time may be either an
available time or a scheduled time
Time
Scheduled Time
Available Time
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Which association? Appointments have times and
dates
Appointment
Date
Time
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Has a Association Appointments have times and
dates
Appointment
Date
Time
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Which association? The Date Book knows which
times are available and which are scheduled
Date Book
scheduled
available
Time
50
Informational Association The Date Book knows
which times are available and which are scheduled
Date Book
scheduled
available
Time
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Which association? If the Date Book schedules
an Event, then a time is scheduled
0..
Event
schedules
1
Date Book
scheduled
Time
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Coexisting If the Date Book schedules an
Event, then a time is scheduled
0..
Event
schedules
1
Date Book
scheduled
Time
53
Things to Keep in Mind

• Not right and wrong
• Depends on the model
• But better and worst
• usable and not usable
• And what I mean and not what I mean

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Building a Class Diagram
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Start with your Transformed Narrative

• A guest calls the hotel at which he or she hopes
  to stay. The clerk asks for the details of the
  planned stay and the desired type of room, checks
  availability, and confirms the reservation.

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Underline the Concrete Objects

• A guest calls the hotel at which she plans to
  stay. The clerk asks for details of the planned
  stay and the desired type of room, checks
  availability, and confirms the reservation.

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Underline the People

• A guest calls the hotel at which she plans to
  stay. The clerk asks for details of the planned
  stay and the desired type of room, checks
  availability, and confirms the reservation.

58
Underline the Forms/Documents

• A guest calls the hotel at which she plans to
  stay. The clerk asks for details of the planned
  stay and the desired type of room, checks
  availability, and confirms the reservation.

59
Underline the Abstract Objects

• A guest calls the hotel at which she plans to
  stay. The clerk asks for details of the planned
  stay and the desired type of room, checks
  availability, and confirms the reservation.

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The 3-6 Key Objects
Concrete Objects
People
Abstract Objects
Forms
Hotel
Guest
Reser- vation
Details
Clerk
Room
61
Identify Key Associations among Objects

• A Hotel has Rooms.
• A Guest stays in a Room.
• A Guest plans to stay at a Hotel.
• A Plan to Stay is recorded as a Reservation.

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A Hotel has Rooms.
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A Guest stays in a Room.
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A Guest plans to stay at a Hotel.
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A Plan to Stay is recorded as a Reservation.
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Problem for the Week
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Modelling In Teams

• identify at least 2 objects from your
  transformed narrative and 1 person
• Write some simple sentences linking them together
• Draw a simple class diagram representing their
  associations with each other