Announcements

1
Announcements

• Prefer building/running programs in class
• yes 23, no 0, answer not so simple 6
• Prefer lecturing from slides
• 3 yes, 18 no, 7 not so simple
• Mixture better than either
• yes 23, no 1, not sure 6
• Comments include that slides are good to have
  available for reference and study

2
486 Phase 2Here is What this Course is not

• Its not just about programming in Java
• or just about Object Oriented Programming
• It is about Object Oriented Analysis Design
• Recall that software engineering is much more
  than programming!
• Its also analysis and design, teams, and other
  things

3
Object-Oriented Analysis and Design in Context

• See life cycle figures from Schach book

4
Some OOA/D Core Skills

• Determine what objects to have
• and what responsibilities each should have
• What is the relationship between responsibilities
  and functionalities?
• Be able to use software design patterns
• that is, logical structures frequently occurring
  in designs and requiring multiple objects to
  implement
• Be able to use UML notation
• Universal Modeling Language is a (large) set
  of semi-graphical notations
• Be able to perform use-case analysis
• One of numerous skills important in analysis and
  design
• (What is it?)

5
What is Analysis? Design?Object-Oriented
Analysis and Design?

• Analysis any detailed examination
• Websters New World College
  Dictionary (4th ed.)
• In software engineering, you examine problems, to
  understand them
• (You dont examine solutions, you build them)
• Therefore analysis refers to
• Examining the problem to be solved

6
What is Analysis? Design?Object-Oriented
Analysis and Design?

• Design
• description of the structure of a solution
• In software engineering, you design software
  solutions
• Therefore design refers to
• Determining the structure of a software artifact

7
What is Analysis? Design?Object-Oriented
Analysis and Design?

• Analysis Do the right thing
• Design Do the thing right
• Larman p.7

8
What is Analysis? Design?Object-Oriented
Analysis and Design?

• OOAD
• Object-Oriented Analysis and Design
• Object-oriented analysis
• Examine the problem to determine its object-like
  parts
• Can be done regardless of implementation language
• Object-oriented design
• Determine how the objects interact and what they
  contain
• One could argue that the analysis/design boundary
  is not exactly ideal

9
Recall Objects

• What is an object??

10
A Definition of Object

• An object is
• A data abstraction
• A bundle of
• Data, and
• Methods (modules containing executable
  statements)
• The bundle is conceptually coherent
• It presents an API
• Inheritance is possible

11
Example of OOAD

• (See Larman section 1.5)
• Player rolls 2 dice a 7 wins, other s lose
• First, define use cases
• Next, define a domain model
• Third, define interaction diagrams
• Fourth, define class diagrams

12
Defining Use Cases

• Use cases are scenarios of system operation
• Use cases are written stories (Larman)
• Use cases are text documents (Larman p. 71)
• Use utilization, purpose, functionality
• Case example, instance, situation
• (suggesting 9 phrases whose meaning use case
• Systems that do lots of things will have lots of
  use cases!
• Is the following is a use case?

13
These are not exactly use cases. Rather this is a
use case diagram. (Figure source OMG Unified
Modeling Language Specification version 1.3,
www.omg.org)
14
First Define Use Cases

• Recall the example
• Player rolls 2 dice 7 wins, other s lose
• Create a use case now

15
Back to Defining the Use Cases

• Larman describes the dice game with
• just 1 use case
• Player rolls dice, winning if they add to 7, else
  losing

16
Second From Use Cases to Domain Model

• Strategy
• Define use cases
• ?Define domain
• model
• ?Define interaction
• diagrams
• ?Define design class
• diagrams

Objective decompose domain into object-like
pieces Try it now then well see what Larman
has
17
Domain Model Example

• This is an entity-relationship diagram
• See Figure 1.3, p. 8 (2nd ed.)
• Note
• name of entity,
• relationship description (1 word),
• relationship numerical property,
• attribute names

18
Third Define Interaction Diagrams

• Given the entities
• Show their possible interactions
• Interactions among objects use
• Messages
• A message is just the name for a method call
• Ill draw the entities
• You draw the interactions
• Then well see what the text has (Figure 1.4, 2nd
  ed.)
• NOTE assume a computerized dice game

• Strategy
• Define use cases
• ?Define domain
• model
• ?Define interaction
• diagrams
• ?Define design class
• diagrams

19
Fourth Define Design Class Diagrams

• This is a basic design for a system
• Show classes in boxes
• List the data members and methods of each class
• Show how many objects of each class interact with
  how many of each other class
• Try it now
• Then well see what text has (Figure 1.5, 2nd ed.)

• Strategy
• Define use cases
• ?Define domain
• model
• ?Define interaction
• diagrams
• ?Define design class
• diagrams