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SJSU – CmpE Fall 2002
Enterprise & Application Frameworks
Dr. M.E. Fayad, ProfessorComputer Engineering Department – RM#
College of Engineering
San José State University
One Washington Square
San José, CA 95192-0180
URL: http://www.cmpe.sjsu.edu/~fayad
Fall 2002 SJSU – CmpE M.E. Fayad L08-S2 Software Stability (1)
2
Lesson 13:Software Stability (1)
Fall 2002 SJSU – CmpE M.E. Fayad L08-S3 Software Stability (1)
Lesson Objectives
Objectives
3
Overview of Previous Lecture Understand the following:
– Enduring Business Theme
– Business Objects
– Industrial Objects
– Framework Layering
Fall 2002 SJSU – CmpE M.E. Fayad L08-S4 Software Stability (1)
Roadmap
4
Scare - General State of Panic
Identify the Killers (Problems)
Catch the killers (Solutions)
Objectives
Fall 2002 SJSU – CmpE M.E. Fayad L08-S5 Software Stability (1)
The Current State of Software - I
5
Current software projects are engineered for the “here and now.”
Changes in the support structure or the software market require massive reengineering projects.
This reengineering costs ridiculous amounts of money.
Fall 2002 SJSU – CmpE M.E. Fayad L08-S6 Software Stability (1)
The Current State of Software - II
6
Software has short life span. Often wrong software application is
implemented Sometimes cancelled before completion maintenance cost over 80% of the
development lifecycle
Fall 2002 SJSU – CmpE M.E. Fayad L08-S7 Software Stability (1)
Sample Problem - The Loan
7
January 1998– I gave a loan of $1000 to one of my students.– He promised to return the money by May 1998.
April 1998– Received an e-mail asking for an extension until
August 1998
March 2002– I have not received the money
Fall 2002 SJSU – CmpE M.E. Fayad L08-S8 Software Stability (1)
Where Is The Problem?
8
After giving this problem to the students in a software engineering class, I received the following responses.– There is no problem.– Take him to court.– Kick his $@%#&!– Ignore it.
What do you think?
Fall 2002 SJSU – CmpE M.E. Fayad L08-S9 Software Stability (1)
A Traditional Model
9
Lender Loan
Borrower
Owes Borrowed
Lent
Do you think this model is an accurate representation of the problem?
Fall 2002 SJSU – CmpE M.E. Fayad L08-S10 Software Stability (1)
Roadmap
10
Scare - General State of Panic
Identify the Killers (Problems)
Catch the killers (Solutions)
Objectives
Fall 2002 SJSU – CmpE M.E. Fayad L08-S11 Software Stability (1)
Problems
11
Wrong Analysis
Industrial Objects
Not stable architecture
Missing the most enduring concepts
Fall 2002 SJSU – CmpE M.E. Fayad L08-S12 Software Stability (1)
Roadmap
12
Scare - General State of Panic
Identify the Killers (Problems)
Catch the killers (Solutions)
Objectives
Fall 2002 SJSU – CmpE M.E. Fayad L08-S13 Software Stability (1)
Open Discussion
13
Problem DomainFriendship
Health
EmploymentFamily
Other Relationships
Borrower
Schedule
Lender
Loan
Education
Expenses
Finance
Needs
Fall 2002 SJSU – CmpE M.E. Fayad L08-S14 Software Stability (1)
EBT-Based Model - The Loan Problem
14…
Friendship{Enduring}
Friend{Business}
Borrower Lender
Finance{Enduring}
Loan{Business}
Solvency{Enduring}
Need{Enduring}
Expenses{Business}
Employment{Business}
Health{Business}
Education{Business}
Family{Business}
Fall 2002 SJSU – CmpE M.E. Fayad L08-S15 Software Stability (1)
Kitchens are systems that we are all familiar with. What makes a kitchen a kitchen? Traditionally, people think of a certain set of objects
when they think of a kitchen:– Stove– Sink– Refrigerator– Dishwasher– etc...
15
Sample Problem II - The Kitchen
Fall 2002 SJSU – CmpE M.E. Fayad L08-S16 Software Stability (1)
The result is a model like this:
16
The Kitchen - A Traditional Model
Kitchen
Cabinet Counter Appliance Sink
Refrigerator Dishwasher RangePantry
Cooktop OvenFreezer
Fall 2002 SJSU – CmpE M.E. Fayad L08-S17 Software Stability (1)
This model has inherent flaws, however.
The model can be thought of as a “tree” of aggregations and generalizations.
Many of the roots of the subtrees can change drastically, causing this model to break.
For example, imagine replacing the appliance node with a Star Trek food replicator... 17
The Kitchen - A Traditional Model
Kitchen
Cabinet Counter Appliance Sink
Refrigerator Dishwasher RangePantry
Cooktop OvenFreezer
Fall 2002 SJSU – CmpE M.E. Fayad L08-S18 Software Stability (1)
To correct this model, one must concentrate on those aspects that do not change over time.
Enduring Business Themes are those concepts that remain constant for a given problem.
Business Objects are those support objects that remain externally stable.
Objects that may be replaced as times change are Industrial Objects.
18
The Kitchen - Correcting The Model
Fall 2002 SJSU – CmpE M.E. Fayad L08-S19 Software Stability (1)
What does a kitchen need? What do people do in a kitchen? What is a kitchen for?
19
The Kitchen - Correcting The Model
Cooking
Cuisine
Livability
Storage
Cleanliness
Convenience
Spaciousness
Fall 2002 SJSU – CmpE M.E. Fayad L08-S20 Software Stability (1)
20
The Kitchen - A Stable Model
Cabinet Pantry
Refrigerator Freezer
Food Storage & Preservation{Enduring}
Microwave
Range
Cooking{Enduring}
Cooktop Oven
Cuisine{Enduring}
Recipe{Business}
Food
Livability{Enduring}
Cleanliness{Enduring}
Convenience{Enduring}
Light{Business}
Counter Shelf
Sink DishwasherWindow Electric Light
Kitchen
Fall 2002 SJSU – CmpE M.E. Fayad L08-S21 Software Stability (1)
Identifying Enduring Business Themes & Business Objects - Identification
Criteria
41
Stability Adaptability Essentiality Explicitness Intuition Tangibility Commonality to the Domain
Fall 2002 SJSU – CmpE M.E. Fayad L08-S22 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S23 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Stability OverTime
Stable Over Time Externally Stable Unstable
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S24 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Stability OverTime
Stable Over Time Externally Stable Unstable
Adaptability AdaptableWithout Change
AdaptableThrough InternalChange
Not Adaptable
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S25 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Stability OverTime
Stable Over Time Externally Stable Unstable
Adaptability AdaptableWithout Change
AdaptableThrough InternalChange
Not Adaptable
Essentiality Essential Essential Replaceable
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S26 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Stability OverTime
Stable Over Time Externally Stable Unstable
Adaptability AdaptableWithout Change
AdaptableThrough InternalChange
Not Adaptable
Essentiality Essential Essential Replaceable
Commonalityto the Domain
Core Core Peripheral
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S27 Software Stability (1)
41
EnduringBusinessThemes
BusinessObjects
IndustrialObjects
Intuition Intuition Intuition andReading
Reading Only
Stability OverTime
Stable Over Time Externally Stable Unstable
Adaptability AdaptableWithout Change
AdaptableThrough InternalChange
Not Adaptable
Essentiality Essential Essential Replaceable
Commonalityto the Domain
Core Core Peripheral
Tangibility Conceptual Semi-tangible Tangible
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S28 Software Stability (1)
41
Enduring Business Themes
Business Objects
Industrial Objects
Intuition Intuition Intuition and Reading
Reading Only
Stability Over Time
Stable Over Time Externally Stable Unstable
Adaptability Adaptable Without Change
Adaptable Through Internal Change
Not Adaptable
Essentiality Essential Essential Replaceable
Commonality to the Domain
Core Core Peripheral
Tangibility Conceptual Semi-tangible Tangible
Explicitness Implicit Sometimes Explicit
Explicit
Identification Criteria
Fall 2002 SJSU – CmpE M.E. Fayad L08-S29 Software Stability (1)
Identification Heuristics - Enduring
49
Enduring Business Themes and Business Objects must be enduring.
Watch out - Long field histories will not necessarily translate to true endurance.
Fall 2002 SJSU – CmpE M.E. Fayad L08-S30 Software Stability (1)
Identification Heuristics - Industrial Object Identification
50
Is the object present in a “classical” model?
Can the object be replaced?
Is the object a representation of a concrete item?
Fall 2002 SJSU – CmpE M.E. Fayad L08-S31 Software Stability (1)
Identification Heuristics - Top-Down Identification
51
Break off conceptual pieces of the problem.
Recursively break these concepts down.
Stop when a layer of industrial objects is reached.
Fall 2002 SJSU – CmpE M.E. Fayad L08-S32 Software Stability (1)
Identification Heuristics - Bottom-Up Identification
52
Start with a “classical” model.
Group the industrial objects under a conceptual “heading.”
Continue this grouping until further grouping is impractical or nonsensical.
Fall 2002 SJSU – CmpE M.E. Fayad L08-S33 Software Stability (1)
Identification Heuristics - There Is No Silver Bullet
53
EBT’s are conceptual themes… Usually
Business objects are more concrete objects… Usually
There are always exceptions to any rule.
Fall 2002 SJSU – CmpE M.E. Fayad L08-S34 Software Stability (1)
34
Security_Manager (I O)
CheckPassword( )
Trait_Gatekeeper (I O)
CheckTraits( )
1 Identity (enduring)1Security (enduring) 11
*1 *1
IDSession (B O)
DomainName : type = string
FindCandidates( )AddPerson( )DeletePerson( )GetPersonProfile( )
11IDManager (B O) 1
PersonIdentifier (B O)
Search( )Search( )
1
1
*PersonProfile (I O)
uniqueID : type = longvalCandidateListGenerator (I O) *1
DataManager (B O)11 11
1
*
PersonTraits (I O)*1
HealthCare Example: PID
Fall 2002 SJSU – CmpE M.E. Fayad L08-S35 Software Stability (1)
• Explain the following statements:
1. Objects should be intelligent agents
2. Mechanism rich and policy free
3. A valuable object works and plays well with others
4. Analysis model should not be too elaborate or too formal
• Explain how to build an analysis model
• Explain how do you make the analysis model more adaptable
35
Discussion Questions
Fall 2002 SJSU – CmpE M.E. Fayad L08-S36 Software Stability (1)
Define: Criteria for Enterprise Frameworks
Let’s discuss of how to build Enterprise Frameworks
T/F:
EBTs are testing patterns.
BOs are stable design patterns.
EBTs + BOs = Framework.
36
Questions for the Next Lecture
Fall 2002 SJSU – CmpE M.E. Fayad L08-S37 Software Stability (1)
Task 1: Essay! Contact me for questions
Task 2: Read Chapters 1 and 2.
Task 3: Design Sessions for SSM (Discuss)
37
Tasks for Next Lecture