SE455 Software Development Methods -- Lecture 1

• Internet connection and basic skills: email, www, ftp
• C++ compiler (Unix or MS Windows, GUI not required)
• Wordprocessor (Everything must be typed.)
• Drawing program (No hand-drawn diagrams.)

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You are required to complete a project of developing a moderate-size software system using Object-Oriented design and implementation techniques.

You may develop any of the following types of programs:

a)
application programs,
such as personal organizers, games, etc.
b)
simulation programs of some real-world systems,
such as traffic control systems.
c)
general-purpose class libraries with demo programs.

If you can't seem to find one, I have an idea for you.

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• Use Object-Oriented design, and implementation techniques.
• Implement the system in C++.
• Around 1,500 lines of C++ source code.
• Work alone.

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Week 2

One-page problem statement.
Problem, scope, and anticipated obstacles.

Week 4

Object-oriented model of the system.
Include class/object/interaction/state diagrams, and class specifications.

Week 7

Object-oriented design of the system.
Apply design patterns. C++ class interface complete.

Week 10

Code complete. Project report.

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Midterm exam

week 6.
Written exam.
All distance-learning students must show up in class, unless there is a conflict. Contact me ASAP.

Final exam

week 11.
Take-home, project report and term paper.

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a)
Develop a template linked list class.
• It should support the usual operations on a list such as insertion and deletion.
• It also supports a Write function that writes the contents of the list to cout.

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b)
Develop a class hierarchy of shapes, which includes:
Shape 
  Closed Shape 
    Circle, Rectangle, ... 
  Open Shape 
    Line, Curve, ... 
  Text 
Each class supports a virtual function Write that writes the attributes of the shape to cout.

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c)
Instantiate a list of shapes. Insert several different shapes into the list, and print out the contents of the list of shapes.

If you have:

• no difficulty --- fine
• some difficulty --- will be ok, read and practice
• major difficulty --- not ready

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To study methods for developing high-quality, large-scale software systemsin a cost-effective manner.

Scale

$>=$ 100,000 LOC

Qualities

reliability, reuseability, extensibility, maintainability.

We will focus on

• philosophies and approaches that are persistent and recurrent rather than fashionable but transient tools and packages;
• long-term adaptability rather than near-term proficiency.

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• Review of object-oriented analysis/modeling.
• Object-oriented design patterns.
• Object-oriented framework.
• Design and implementation techniques in C++.
• Testing and debugging techniques.

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Problems:

• Low quality
• High development/maintenance cost
• Long delays
• High cancelation rate

Reasons:

• Complexity
• Evolution and longevity
• Diverse user needs and high expectations

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Solutions:

• Control complexity
• Enhance flexibility and extensibility
• Promote reuseability

Today's technology --- Object-Oriented methodology.

Tomorrow's technology --- automation, Computer-Aided Design.

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• Addresses some of the critical problems.
• Evidence and data show it works.
• Has matured in the past a few years and acquired industry support.
• Radically different from the traditional practice.

Review basics of OO:

• Fundamental elements of OO.
• Notations for OO analysis and design.

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Major elements:

Abstraction

capture the essential characteristics

Encapsulation

separate interface from implementation

Modularity

decompose system into a set of cohesive and loosely coupled modules

Hierarchy

bring an order to abstraction

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Minor elements:

Typing

enforce that objects of different types are not interchangeable.

Concurrency

allow active objects, or multiple threads of control

Persistence

existence transcends time and/or space

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• Leading methods: Booch and OMT
• New standard: Unified Modeling Language (UML)
• Diagrammatic notations:
  • Class diagram: classes, data, operations, and relationships.
  • Object diagram: objects or instances, data, and relationships for objects.
  • State diagram: dynamic behavior within a class or object.
  • Interaction diagram: dynamic behavior among objects.
  • Use-case diagram: system behavior and scenarios from the users' perspective.

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To attain and maximize the following design qualities:

• Soundness: reliable, logical, feasible
• Modifiability: changeable, extensible, reusable
• Clarity: concise, understandable, well-structured
• Efficiency: minimum consumption of time and system resources

Challenges:

• Balancing conflicting goals.
• Managing trade-offs.
• Satisfying multiple constraints.

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• There are desirable qualities but no quantifiable measurements.
• It can not be taught, but can only be learned through
  • studying the masterpieces
  • practice and experience
• Techniques are only the tools for expression, what's more important is the sense of appreciating ``beauty.''
• Software design is a creative activity! Have fun!

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Recommended reading Booch Chapters 1 through 5.

Problem statement of your course project. (Even if you choose to do the project suggested by in the instructor.)

Next week's topics:

• Review of OO modeling, case study (Booch Chapter 8)

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Index of Slides