Transcript Software Product Len Engineering

Software Product-Line
Engineering: A FamilyBased Software
Development Process:
Defining The Family
David Weiss
[email protected]
FAST Process
• A process for defining families and developing
environments for generating family members
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Find abstractions common to the family
Define a process for producing family members
Design a language for specifying family members
Generate software from specifications
• Family-oriented Abstraction, Specification,
Translation
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A FAST Process
Investment
Domain Engineering
Feedback
Product Engineering Environment
Product Engineering
Payback
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Products
3
The Domain Model
• Conceptual Framework
– Family Definition
• Commonalities and Variabilities Among Family Members
• Common Terminology for the Family
• Decision Model
– Economic Analysis
– Product Line Architecture
– Optional: Application Modeling Language (AML): Language
for stating requirements
• Mechanism for generating products
– Composer or Compiler (AML)
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The Conceptual Framework (1)
• Qualify The Domain
– Is it economically viable?
– Artifact: Economic Model
• Define The Family
– What do members of the family have in common and how do
they vary?
– Artifact: The Commonality/Variability Analysis
• Define The Decision Model
– What decisions must be made to identify a family member?
– Artifact: The Decision Model Table
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The Conceptual Framework (2)
• Create The Architecture
– What is a good modular structure and a good uses
structure?
– Artifacts: Module Guide, Interface Specifications, Uses
Relation
• Design The System Composition Mapping
– What modules are needed for which decisions?
– Artifacts: System Composition Mapping, Uses Relation
• Design The Product Engineering Environment
– What are good mechanisms for using the decision model to
produce products or to generate products from the AML?
– Artifacts: Decision Model GUI, Generator or Compiler (AML)
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Defining Requirements For The Family: The
Commonality Analysis
• Must specify requirements that are
– common to all family members (commonalities)
– variable among family members (variabilities)
• Commonalities: Assumptions that hold for every member of
the family
• Variabilities: Assumptions that define the range of variation
for the family
• Parameters of Variation: Quantification of the variabilities
• Dictionary of terms
– Technical terms that define a vocabulary for the domain
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Organization of A
Commonality/Variability Analysis
1.
2.
3.
4.
5.
6.
7.
8.
Introduction & Overview
Commonalities
Variabilities
Parameters of Variation
Dictionary
Issues
Notes
Review Questions
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The Floating Weather Station: An
Example
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The Floating Weather Station
• Floating Weather Station (FWS) buoys are deployed
at sea and periodically report the current wind speed
via messages sent by radio. Each member of the
FWS family contains an onboard computer that
controls the operation of the buoy while it is at sea.
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A Few FWS Commonalities
The following statements are basic assumptions about
the FWS domain, i.e., they are true of all FWS systems.
C1. At fixed intervals, the FWS monitors the wind
speed at its location.
C2. The FWS is equipped with one or more sensors
that monitor wind speed.
…
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A Few FWS Variabilities
The following statements describe how FWS may vary.
V1. The number of wind speed sensors on a FWS may
vary. (C2)
V2. The sensor period of the sensors on a FWS may
vary (C1, C2)
…
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A Few Parameters of Variation
Parameter
Meaning
P1. SensorCount Number of
(V1)
wind sensors
P2. SensorPeriod Sensor period
(V2)
Value Set
Binding
Time
Specification
Default
[1..600] sec. Specification
5
[1..5]
…
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1
Dictionary of Terms
Term
Meaning
Sensor period
The number of seconds
between sensor readings
Wind speed
The speed of the wind in
knots: nautical miles per
hour
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From Parameters Of Variation To
Implementations: The Decision Model
System Composition Mapping
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Customer(s)
Decision
Model
Validation &
Acceptance
Delivered System
Decisions
Code & Documentation
Requirements
Engineer Application
Components+
Tools+
Processes
Key:
Process
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Artifact
Summary
• Product Line Scope Is Defined By
Commonality/Variability Analysis
• Commonalities Define What’s Common To All Family
Members
• Variabilities Define The Range Of The Family
• Parameters Of Variation Quantify The Range
• Decision Model Uses Parameters of Variation In
Specifying Individual Products
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Terminology
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Family
Product Line
Conceptual Model
Domain Engineering
Domain Model
Product Engineering (aka Application Engineering)
Product Engineering Environment
Decision Model
Commonality/Variability Analysis
System Composition Mapping
Application Modeling Language
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“If I have seen farther than others
it is because I have stood on the
shoulders of giants.”
-- Isaac Newton
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“Everything should be as simple as
possible, but no simpler.”
-- Albert Einstein
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Exercise 3: Scoping A Family
Part 1
For the family you proposed in Exercise 1, define 3
commonalities and 3 variabilities
Commonalities
1.
2.
3.
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Exercise 3: Scoping A Family
Part 1 (cont)
For the family you proposed in Exercise 1, define 3
commonalities and 3 variabilities
Variabilities
1.
2.
3.
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Exercise 3: Scoping A Family
Part 2
Review the Commonality/Variability Analysis for the
FWS
Issues:
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Exercise 3: Scoping A Family
Part 3
Propose one new commonality and (at least) one new
variability for the FWS.
Commonality:
Variability:
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FWS Commonalities
The following statements are basic assumptions about the FWS domain, i.e., they are true
of all FWS systems.
Behavior
C1.
At fixed intervals, the FWS transmits messages containing an approximation of
the current wind speed at its location.
C2.
The wind speed value transmitted is calculated as a weighted average of the
sensor readings, calculated over several readings for each sensor.
Devices
C3.
The FWS is equipped with one or more sensors that monitor wind speed.
C4.
The FWS is equipped with a radio transmitter that enables it to send messages.
C5.
Each sensor comes equipped with a software driver for it and a unique
identifier. (See Appendix II for association of sensors and identifiers.)
C6.
Each sensor on board a FWS has a way of indicating its reliability.
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FWS Variabilities
The following statements describe how a FWS may vary.
Behavior
V1. The formula used for computing wind speed from the sensor readings may vary. In
particular, the weights used for the high resolution and low resolution sensors may
vary, and the number of readings of each sensor used (the history of the sensor) may
vary.
V2. The types of messages that an FWS sends may vary according to both content and
format. There are currently only two types of messages, described in section 8.,
Appendix I.
V3. The transmission period of messages from the FWS may vary.
Devices
V4. The number of wind speed sensors on a FWS may vary.
V5. The resolution of the wind speed sensors may vary.
V6. The sensor period of the sensors on a FWS may vary.
V7. The wind speed sensor hardware on a FWS may vary.
V8. The transmitter hardware on a FWS may vary.
V9. The method used by sensors to indicate their reliability may vary.
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Teams
Role
Responsibility
Systems Engineer
Commonality/variabili
ty analysis, decision
model
Architect
Module, uses, process
structures, interface
specifications
Developer
Module implementation
Module tests, System
generation and
verification
Economic model,
project plan
Tester & Integrator
Project Manager
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Person