CMPT 370: Information Systems Design

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CMPT 370 Information Systems Design
Lecture Topic Anti Patterns

• Instructor Curtis Cartmill, Simon Fraser
  University Summer 2003

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Objectives

• So far we have focused on proper design tools and
  techniques in information system design
• We can also learn from solutions that we have
  encountered in the past
• The anti pattern is a recognition of an incorrect
  solution within a context and presents a common
  solution that refactors the system to maximize
  benefits and minimize consequences
• Anti patterns have their genesis in a book
  entitled Anti Patterns Refactoring Software,
  architectures and Projects in Crisis

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What is an Anti Pattern

• Anti Patterns are negative solutions that present
  more problems than they address
• Represents the difficulty in translating business
  concepts into software solutions
• Anti Patterns are a natural extension to design
  patterns
• focused on the wide and ever-growing selection of
  repeated software failures in an attempt to
  understand, prevent, and recover from them.
• Anti Patterns bridge the gap between
  architectural concepts and real world
  implementations
• Understanding anti patterns provides the
  knowledge to prevent or recover from them
• Anti Patterns represent the latest concept in a
  series of revolutionary changes in computer
  science and software engineering thinking.

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Why are Anti Patterns so persuasive
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Why study Anti Patterns
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Anti Patterns differ from simple patterns

• AntiPatterns begin with a compelling, problematic
  solution.
• From this solution, a discussion of the root
  causes records how the problematic solution is
  the result of incorrectly resolving the forces
  for a specific underlying set of problems within
  its context.
• This convergence from a concrete situation to the
  more abstract underlying forces is a key
  component in communicating an understanding of
  how and why the problem exists.
• This abstraction is composed of symptoms and as
  consequences, similar to the context and forces
  of a design pattern, but which clearly documents
  the implications of the problematic solution.

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Anti Patterns differ from simple patterns

• The documented symptoms can then be critical cues
  used in the diagnosis and recognition of a
  specific problematic solution, or, Anti Pattern.
• Finally, once an Anti Pattern has been correctly
  identified, its refactored solution can be used
  to obtain a better convergence of the underlying
  forces to lead you to a better understanding of
  the problem and an effective method of resolving
  the problematic solution

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Anti Patterns contrast to Design Patterns
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Anti Pattern template
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Anti Patterns are abstractions of experience
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Applications of Patterns
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Yesterdays solution lead to tomorrows Anti
Pattern
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Development Anti Patterns
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Architecture Anti Patterns
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Management Anti Patterns
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Development Anti Pattern Spaghetti Code
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Development Anti Pattern Spaghetti Code
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Development Anti Pattern Spaghetti Code
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Development Anti Pattern Spaghetti Code
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Development Anti Pattern Spaghetti Code
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Development Anti Pattern The Blob
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Development Anti Pattern The Blob
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Development Anti Pattern The Blob
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Development Anti Pattern The Blob
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Development Anti Pattern The Blob
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Development Anti Pattern The Blob
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Development Anti Pattern - Poltergeist
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Development Anti Pattern - Poltergeist
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Development Anti Pattern - Poltergeist
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Architecture Anti Pattern - Stovepipe
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Architecture Anti Pattern - Stovepipe
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Anti Patterns Ground Rules