Designing Patterns, Templates and Policy-Based Design Training

The book Design Patterns by the "Gang of Four" (i.e., the "GOF") introduced the idea of patterns to the software development community. This seminar offers a novel view of design patterns, focusing on how templates can make working with patterns more effective. The seminar also describes policy-based design (PBD), a template-based technology introduced in Andrei Alexandrescu's Modern C++ Design that can generate dozens of implementations for the same pattern, each embodying a unique set of design trade-offs.

• A knowledge of which pattern names are most important to know.
• Familiarity with a number of common design patterns, including less frequently known variations.
• An exposure to template metaprogramming.
• An understanding of how template technology can be used to help generate pattern implementations.
• A familiarity with the implementation and application of policy-based design.

Format: Lecture and question/answer. There are no hands-on exercises, but participants are welcome to use their computers to experiment with the course material as it is presented.

• Brief review of design patterns and programming idioms.
  • Why study design patterns?
  • The most important pattern names to know.
  • Patterns vs. code
    • Common variations in the Factory pattern
• Visitor and variations:
  • The classic GOF Visitor pattern
  • The Visitor encapsulation problem
    • How the Private Inheritance pattern can address it
  • The Acyclic Visitor pattern, its pros and cons
  • The Ad Hoc Visitor technique:
    • Typelists
    • Template metaprogramming to generate cascading type tests
• Two views of Observer:
  • Summary of the classic GOF Observer pattern
  • A template-based approach built on tr1::function:
    • Overview of TR1 and Boost
    • Using tr1::function to eliminate the Observer base class
    • Advantages and disadvantages of the approach
• Singleton and Related Patterns:
  • The classic GOF Singleton pattern, its pros and cons
  • Meyers' variant
  • The Monostate pattern
  • Singleton and thread-safety
    • The Double-Checked Locking pattern and why it's not safe in C++
• Policy-Based Class Design (PBD):
  • What it is
  • Alexandrescu's PBD approach to Singleton
    • Identification of orthogonal policy issues
    • Implementing policies via templates
    • The Loki library
    • Using policies via template template parameters
    • Pros and cons of this approach
  • PBD and generative programming
• Sources for Additional Information

Upcoming Dates & Locations