Frameworks and Design

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Frameworks and Design

• CS2340

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References

• Building Application Frameworks Object-Oriented
  Foundations of Framework Design Mohammed Fayed,
  Douglas Schmidt, Ralph Johnson Wiley 1999
• Framework-Based Software Development in C
  Gregory Rodgers Prentice Hall 1997

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Definition-What is a framework?

• A reusable design that describes how system in
  decomposed into objects.
• A class library that captures interaction
  patterns between objects.
• A set of abstract and concrete classes

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Framework Issues

• Development Complexity
• Learning Curve (Usability)
• Extensibility
• Maintainability
• Validation
• Efficiency
• Composition

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Framework design Issues

• KISS Keep it simple (7 /- 2 Rule)
• May use cliques (mini-frameworks) GUI vs. Drawing
• Help user be productive quickly
• Identify tools for task (Internal vs. External)
• Use real-world knowledge to speed understanding
• Be consistent
• Dont make things almost the same

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Framework design issues

• Design to prevent user errors (i.e. Adopt/Orphan
  naming conventions)
• Have default behavior
• Be modeless
• Provide immediate and reversible results
• Have documentation
• Especially interactions
• Framework not equal to Class Library

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Framework Development

• Domain Analysis
• Architectural Design
• Framework Design
• Framework Implementation
• Framework Testing
• Documentation

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Domain Analysis

• Context Analysis
• Abstraction Modeling
• Domain Architecture (Clustering)
• Basically we want to figure out important
  concepts and their relationships. Then we
  prepare models that are used in later parts of
  the design. Focus is on the problem space and
  problem category.

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Architectural Design

• Frequently uses
• Layers
• Roles
• Translate Domain Architecture into something that
  can be implemented, tested, extended and
  maintained.
• Enforcing constraints via the architecture can be
  challenging.

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Case study of a framework

• Sunit unit testing frameworks
• Domain analysis
• What are concepts in domain of testing?

Test Case Test Suite Test Fixture Test Check Test
Result Something to run the tests
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SUnit Architecture
TestCase uses the Command Pattern, implements
abstract run interface. Run is a Template Method
Pattern run setUp runTest
tearDown TestSuite Composite Pattern
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JUnit Architecture
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Coming up

• M5 due one week from today (11/04)
• Next time Grammars Parsing
• Next week Alan Kay video