Design Patterns: Summary and Next Steps

1
Design Patterns Summary and Next Steps

Y. NARAHARI Computer Science and
Automation INDIAN INSTITUTE OF SCIENCE Bangalore
560 012 hari_at_csa.iisc.ernet.in
2
Design Patterns

• Analysis to Design Model
• Best Design Practices to be used by everyone
• Provide a common vocabulary
• Documentation/ Learning Aid
• Find appropriate Objects
• Design of application programs, toolkits,
  frameworks, middleware
• Everyday life

3
Current Scenario

• CASE tools are being developed
• Pattern Specification Languages
• Mining of Patterns
• Discovering Patterns from Code
• Domain Specific Patterns
• Patterns for Concurrent/Distributed Computing,
  Embedded Computing

4
Myths About Design Patterns

• It is enough to know about DPs
• Analysis
• Architecture
• Data Structures
• Algorithms
• Technologies
• DPs solve all problems
• Complete automation is possible

5
Space of Patterns

• Analysis Patterns
• Architectural Patterns
• Design Patterns
• Idioms
• Anti-Patterns
• Meta-Patterns
• Domain Specific Patterns
• Architecture Specific Patterns (J2EE, CORBA, Web
  Services)
• Continuously Evolving

6
Design Best Practices

• Program to Interface
•  Interface implementation
• Postpone binding
• Postpone object creation
• Effective use of polymorphism
• Effective use of reuse mechanisms
• Decouple senders and receivers
• Classes should be neither tightly coupled nor
  loosely coupled but optimally coupled
• Encapsulate variation

7
Design Best Practices (Contd)

• Objects as arguments
• Recursive composition
• Transparent Enclosure
• Single Child Composition
• Correct use of hierarchy
• Design for change
• Create objects indirectly

8
To Probe Further Books

• Gammas book Java Version
• Martin Fowler Analysis Patterns
• Buschmann et al - Pattern Oriented Software
  Architecture (Volume 1)
• Douglas Schmidt et al Patterns for Concurrent
  and Distributed Systems
• Arthur Riel OO Heuristics
• Mary Shaw and David Garlan Software
  Architecture
• Jim Conallen Web Applications using UML

9
To Probe Further Websites

• Patterns Homepage http//hillside.net/patterns/
• Homepages of Douglas Schmidt, Martin Fowler,
  Mary Shaw, Buschmann
• http//lcm.csa.iisc.ernet.in/hari
• http//www.rational.com