l2-s1modeling 2003 sjsu -- cmpe advanced object-oriented analysis & design dr. m.e. fayad,...

2003 SJSU -- CMPE L2-S1 Modeling

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 95192-0180

http://www.engr.sjsu.edu/~fayad

2003 SJSU – CMPE ---- M.E. Fayad L2-S2 Modeling

2

Lesson 2:Modeling


Lesson Objectives

Objectives

3

Understand modeling Why we model? Discuss model essentials Explore different models Understand the differences

between a method and a process Understand the differences

between multiple models and

multiple views


Define:

– Standards

– Methodologies

– Method & Process

– Model & View

– Tools

– Environments

4

Definitions


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

Standards

[Fayad-Laitinen 1998]


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

Standards



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

Methodology



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

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

Methods or Techniques


10

POM vs. OOM

Procedural

Self-Disciplined

Unconstrained

Free-Form

Object-Oriented

Teamwork

Rigorous

Standardized


11

Method Provides Foundation for Software Engineering

Step-By-Step Process

Notation That SymbolizesObject-Oriented Principles

Communication Medium ForNon-Programmers

Framework For ModelingThe Program

Standards For TransitioningThe Problem BetweenSoftware Engineers

Requirements

PreliminaryDesign

DetailedDesign

Code andUnit Test

Integration andSystem Testing

Maintenance

pac k age Fac toria l_Pac k age is s ubty pe Argument_SubTy pe is In teger range 0 .. In teger' Las t; s ubty pe Res ul t_SubTy pe is In teger range 1 .. In teger' Las t;

func tion Fac toria l_Of (Value : Argument_Subty pe) re turn Res ul t_Subty pe;

end Fac toria l_Pac k age;

SoftwareReqmts

SpecSoftwareDesign

Document

SoftwareDesign

Document

SoftwareChangeProposal


12

The Myth of the Single Software Development Method

FIDO

Requirements Such AsSizeReliabilitySafetyCostScheduleMaintainability

Require DifferentMethodsToolsQuality AssuranceMaterialsPersonnelDocumentation


13

How Many OO Methods Exist?

.

UML


14

Engineering Process Hierarchy

Engineering

Computer Electronics

SoftwareHardware

SASD OOT

UML

Scientific Area

Standards

Methodologies(Macrodevelopment Processes)

Techniques (Methods)(Minidevelopment Processes)

Processes(Microdevelopment Processes

OMT

Identify Classes

IdentifyAttributes


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”

x x xx x

o o o

o

o

x

x

oo

o

x

Big Play

x x xx xo o o oo

x

x

oo o

x

Long Kick


16

Method vs. Process

Processes take OO methods out of the classroom and put them to workProcesses take OO methods out of the classroom and put them to work

• Theoretical

• Ideas

• Predictions

• Practical

• Concrete Actions

• Metrics


17

Defined Processes are Baseline for Improvements

Can’t improve anything that you can’t repeat

.

Planned vs. Actual Budget

500

1000

1500

2000

2500

3000

3500

Hou

rs

J an Feb Mar Apr M ay J un J ul Aug Sep

Planned

Ac tual

Automated Testing Process

Improved Processes Metric Feedback

Tem per at ureTr ansducer s

M odel3. 2.1. 4. 11

Tem perat ur eTr ansducers

I nter face3. 2.2. 9

I ce Det ectorM odel

3. 2.1. 4.14

Ai r Dat a U nitM odel

3. 2.1. 4.1

Modify_OAT_WAT_Diff

OAT_WAT_Dif f

U p da t e_ T e mp _T r nd c rs

Mach_NumberS ta t ic _ P re s su r e

Measured_OAT_WAT_Diff

Measur ed_OAT_WAT_Diff

Updat e_I ce_Detect or

OAT_WAT_Dif f_Voltage

Temp_Tr ndcrs_BIT_State

T e m p _ Tr n dc r s_ S t at e

Measur ed_St at ic_Pressur e

Measur ed_St at ic_Pressur e

O bje c t In te rac tio n D iagr am ( O ID )

Technology Infusion

Process Improvements

SoftwareDevelopmentProcesses

UPDATED

SoftwareDevelopmentProcesses


18

Software Process Hierarchy

.

Projects

Software Pro cess

Software Pro cess

Pro

jec

t 2

Software Pro cess

Pro

jec

t 3

Pro

jec

t 2

Pro

jec

t 1

3

XYZ Company

SoftwareEngineeringGuidebooksManual

Company2Industry /Government1

Software Engineering Institute

CapabilityMaturity Modelfor Software

FEDERALSTANDARD

FAA - 178A

DoD-STD-2167A

MILITARYSTANDARD


19

General Processes Must be Tailored to Your Projects

SQAReviewer

Reader

Designer

PreliminaryDesign

Reviewer

Moderator

S/W TechLead

ReworkPerfor m furt her r ework of th e

deta iled design. Prese nt minorrewor k to SQA Reviewer and

major rewor k to S/ W Tech Lea d.

Are allminor defects

reworked?

Are al lmajor defects

reworked ?

Follow-UpInfo rm de signer that de taileddesign passed in spection.Add specificat io n units int o

curr ent CM S libr ary.

Yes

Yes

No

No

SoftwareEngineeringPracticesManual

Detailed ProcessesDependent on:

General

Specific

Application Area Methods Tools Language

Software Inspection Process


20

Identifying Appropriate Process Details

Cost effective range– depends upon environment– specifies “who”, “what”, “when”– reference “how”

Too Much• not cost effective

• typically too much “why”

Not Enough• useless

• typically only “what”


21

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


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

Modeling – Definition

Any single thing can be represented by a large number of models


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

Objectives of Modeling


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

Modeling and Model


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

Principles of Modeling


26

Model Essentials Simple

Complete (most likely to be correct)

Stable to technological changes

Testable

Easy to understand

Visual or graphical

[Fayad98]


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

Summary: Models Serve Several Purposes

Testing a physical entity before building it

Communication with customers

Visualization

Reduction of complexity


29

Modeling Classifications [1]

Tangible

– Physical

– Examples

• Mall

• Aircraft

Intangible

– Logical

– Examples

• Flowcharts

• STDs

• DFDs


30


Static

– Object models

– Domain models

– DFDs

Dynamic

– Behavior models

• Flowcharts

• Petri-Net

– Three properties:

Control, Behavior, Time


31


Object Model (class diagram)

Control Model (STDs, FlowCharts, Activity Diagrams, OIDs)

Transformation Model (DFDs)


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


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


34

Tools: Select Tools to Meet Specific Needs

Correct Tool For The JobMaximum Benefit FromRealistic Expectations

Simple Tools Can OftenBe Invaluable

WARNING:All Tools Are Not Equal!

Wrong Type Of Tool For Job

Frustrates Users

Seldom Ends In Success

Underpowered Tool

Reduces ConfidenceIn CASE Technology

Often Arise FromUnrealistic Expectations

Overpowered Tool

Wastes Money and Time

May Be Inflexible

STOP


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

Discussion Questions (1)


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

Discussion Questions (2)


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

Questions for the 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 e-mail me, the team name, team’s members’ names, their e-mails, 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

Tasks for Next Lecture

l2-s1modeling 2003 sjsu -- cmpe advanced object-oriented analysis & design dr. m.e. fayad,...

Documents