1. Advanced Object-Oriented Analysis & Design
Dr. M.E. Fayad, Professor
Computer Engineering Department, Room #283I
College of Engineering
San José State University
One Washington Square
San José, CA
2003
SJSU -- CMPE

2. SJSU – CMPE ---- M.E. Fayad
Lesson 2:
Modeling 2
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SJSU – CMPE M.E. Fayad

3. SJSU – CMPE ---- M.E. Fayad
Lesson Objectives
Understand modeling
Why we model?
Discuss model essentials
Explore different models
Understand the differences
between a method and a process
between multiple models and
multiple views 3
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4. SJSU – CMPE ---- M.E. Fayad
Definitions
Define:
Standards
Methodologies
Method & Process
Model & View
Tools
Environments 4
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Standards
Standards imply regulations, guidelines, rules, laws, and so on.
Standards can dictate named methodologies, such as IEEE standards or DOD standards (Ex: DOD-STD-2167A).
A standard alone is not sufficient on getting a task completed. Why? 5
[Fayad-Laitinen 1998]
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6. SJSU – CMPE ---- M.E. Fayad
Standards
Because standards focus on the attributes of the results instead of how the results will be achieved
A standard also includes a type, model, or example commonly or generally accepted or adhered to, such a criterion set for usage or practices (moral standards)
Standards applies to some measure, principle, model, and so on, with which things of the same class are compared to determine their quantity, value, quality, and so forth (standards of purity in drugs) 6
[Fayad-Laitinen 1998]
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Methodology
A methodology is “a science of method or orderly arrangement” Webster.
A methodology is used to refer to the very highest level of the way we do things.
A methodology also refers to “a system of methods, as in particular science”
The methodology we will consider here cover only the development of software applications. 7
[Fayad-Laitinen 1998]
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Methods or Techniques
A method implies a regular, orderly, logical procedure for doing something, such as a method of finding software requirements.
Exs: Waterfall model, spiral model [Boehm84], and fountain model [Henderson-Selers90].
Jacobson defines a method as a planned procedure by which a specific goal is approached step by step [Jacobson92].
Examples of software design method are a set of work procedures, a set of notations, or a set of heuristics. 8
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Methods or Techniques
Software engineering methods can be divided into three major categories:
1. Process-Oriented Methods [Yourdon89]
2. Data-Oriented Methods [Martin90]
3. Object-Oriented Methods [Fayad93, Rumnaugh91, etc..] 9
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POM vs. OOM 10
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11. Method Provides Foundation for Software Engineering11
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12. The Myth of the Single Software Development Method12
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13. How Many OO Methods Exist?
UML 13
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14. Engineering Process Hierarchy
Scientific Area
Standards
Methodologies
(Macrodevelopment Processes)
Techniques (Methods)
(Minidevelopment Processes)
Processes
(Microdevelopment Processes
Computer
Electronics
Hardware
Software
SASD
OOT
UML
OMT 14
Identify
Classes
Identify
Attributes
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15. Processes are Important for a new OO Teams
New methods and tools introduce confusion
Processes define exactly who, what, when, and how
“big-picture” 15
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Method vs. Process
Processes take OO methods out of the classroom and put them to work
Theoretical
Ideas
Predictions
Practical
Concrete Actions
Metrics 16
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17. Defined Processes are Baseline for Improvements17
Can’t improve anything that you can’t repeat
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18. Software Process Hierarchy18
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19. General Processes Must be Tailored to Your Projects19
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20. Identifying Appropriate Process Details
Too Much
not cost effective
typically too much “why”
Cost effective range
depends upon environment
specifies “who”, “what”, “when”
reference “how”
Not Enough
useless
typically only “what” 20
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21. SJSU – CMPE ---- M.E. Fayad
Modeling
Model building is a well established human tradition, e.g.
Ancient Egyptian built models for their pyramids and temples
Early ship builders produced physical models for the British Admiralty
Building plans
Electronic schematics
Physics 21
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22. Any single thing can be represented by a large number of models
Modeling – Definition
Building a model is a well-established human process.
A model is a description of something.
Models allow us to answer questions about a real thing before we build it.
Models capture only those features deemed essential by model builders for their goals.
A single thing might be represented by multiple model.
Models can be validated. 22
Any single thing can be represented by a large number of models
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SJSU – CMPE M.E. Fayad

23. Objectives of Modeling
To communicate the desired structure and behavior of the system
To visualize the system’s architecture
To better understand the system we are building
To serve as a template that guide us in constructing a system
To expose opportunities for simplification and reuse
To document the decisions made
To manage risk 23
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24. SJSU – CMPE ---- M.E. Fayad
Modeling and Model
Modeling
A central part of all the activities that lead up to the deployment of good software.
Model
A simplification of reality
Provides the blueprint of a system 24
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25. Principles of Modeling
The best models are connected to reality
No single model is sufficient. Every nontrivial system is best approached through a small set of nearly independent models 25
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26. SJSU – CMPE ---- M.E. Fayad
Model Essentials
Simple
Complete (most likely to be correct)
Stable to technological changes
Testable
Easy to understand
Visual or graphical 26
[Fayad98]
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27. Modeling in this Course
In this course, we will focus on the job of modelers:
How they collect facts/requirements about the application domain from different sources
How they prepare models of the application domain
How they limit their modeling activities
How they create one or more models of the target system
How they use models to create blueprints and architect software
How they test and validate their models 27
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28. Summary: Models Serve Several Purposes
Testing a physical entity before building it
Communication with customers
Visualization
Reduction of complexity 27
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29. Modeling Classifications [1]
Tangible
Physical
Examples
Mall
Aircraft
Intangible
Logical
Examples
Flowcharts
STDs
DFDs 29
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30. Modeling Classifications [2]
Static
Object models
Domain models
DFDs
Dynamic
Behavior models
Flowcharts
Petri-Net
Three properties:
Control, Behavior, Time 30
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31. Modeling Classifications [3]
Object Model (class diagram)
Control Model (STDs, FlowCharts, Activity Diagrams, OIDs)
Transformation Model (DFDs) 31
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32. Modeling Classifications [4]: UML
Static
Type diagrams, CRC cards, use case Model, use case diagrams, and class diagrams
Dynamic or Behavior
Activity diagrams, collaboration diagram, sequence diagram, and state diagram
Implementation
Component diagram & deployment diagram 32
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33. Multiple Models vs. Multiple Views
UML has 9 different models.
This called “multiple models” and represents:
Abstraction, what and how, etc.
It is not “multiple views”
Multiple view represents:
Presentations
Levels, layers, slices, details
Scalability, accessibility, authorization, information hiding, dimensions 33
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34. Tools: Select Tools to Meet Specific Needs34
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35. Discussion Questions (1)
What are the differences between multiple models and multiple views?
T/F
UML stands for United Modeling Level.
Use case diagrams are behavior models.
Data flow diagrams are tangible models.
Decision tables are control models.
Petri nets are static models
Software design is part of UML.
What are the properties of software process?
What are the essential properties of the model? 35
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36. Discussion Questions (2)
Define: Static models, dynamic models, transformation models
What are the differences between a method and a process?
What are the differences between tangible and intangible modeling?
Identify examples of tangible modeling in system development
Identify examples of intangible modeling in system development
“System development is model building.” Please describe.
“Models serve several purposes.” Please describe.
Essay Topic 1: Multiple Models vs. Multiple Views
Essay Topic 2: Mapping from models to views 36
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37. Questions for the Next Lecture
Discuss the following guidelines
Go Beyond the Problem Domain
Speculate About Likely Changes
Separate General Functionality from Specific Policy
Object should have Cohesive Interfaces
Objects Should Be Intelligent Agents
Objects Should Export Services
Avoid “Object Machismo” 37
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38. SJSU – CMPE ---- M.E. Fayad
Tasks for Next Lecture
Task 1: Problem Statement for team projects are needed (see sample problems on OOPSLA – DesignFest). This is due on the third week of the semester.
Task 2: Identify the team members of your team. Select a team name and me, the team name, team’s members’ names, their s, phone numbers -- Immediately.
Task 3: Think about extra assignments and writing essays. E- mail me if you like to start right away.
Please note that problem statements must be submitted electronically as MS Word format. 38
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