Anti-pattern

Anti-patterns, also referred to as pitfalls, are classes of commonly-reinvented bad solutions to problems. They are studied, as a category, in order that they may be avoided in the future, and that instances of them may be recognized when investigating non-working systems.

The term originates in computer science, apparently inspired by the Gang of Four's Design Patterns book, which laid out examples of good programming practice. The authors termed these good methods "design patterns", by analogy with the term as used in architecture. "Anti-patterns", as described in the book by Brown, Malveau, McCormick and Mowbray, are a natural counterpart, though not mentioned in the original Design Patterns book. Part of good programming practice is the avoidance of anti-patterns.

The concept is readily applied to engineering in general, and also applies outside engineering, in any human endeavour. Although the term is not commonly used outside engineering, the concept is quite universal.

Some recognised Software development anti-patterns

For a more comprehensive, alphabetical list, see Category:Anti-patterns.

Project management anti-patterns

Smoke and mirrors: Demonstrating how unimplemented functions will appear
Software bloat: Allowing successive versions of a system to demand ever more resources

Design anti-patterns

Abstraction inversion: Not exposing functionality required by users, so that they re-implement it using higher level functions
Ambiguous viewpoint: Presenting a model (usually OOAD) without specifying its viewpoint
Big ball of mud: A system with no recognisable structure
Blob: see God object
Gas factory: An unnecessarily complex design
Input kludge: Failing to specify and implement handling of possibly invalid input
Interface bloat: Making an interface so powerful that it is too hard to implement
Magic pushbutton: Implementing the results of user actions in terms of an inappropriate (insufficiently abstract) interface
Re-Coupling: Introducing unnecessary object dependency
Stovepipe system: A barely maintainable assemblage of ill-related components
Race hazard: Failing to see the consequence of different orders of events

Object-oriented design anti-patterns

BaseBean: Inheriting functionality from a utility class rather than delegating to it
Empty subclass failure: Creating a (Perl) class that fails the "Empty Subclass Test" by behaving differently from a class derived from it without modifications
God object: Concentrating too many functions in a single part of the design (class)
Object cesspool: Reusing objects whose state does not conform to the (possibly implicit) contract for re-use
Poltergeists: Objects whose sole purpose is to pass information to another object
Yo-yo problem: A structure (e.g. of inheritance) that is hard to understand due to excessive fragmentation

Programming anti-patterns

Accidental complexity: Introducing unnecessary complexity into a solution
Action at a distance: Unexpected interaction between widely separated parts of a system
Accumulate and fire: Setting parameters for subroutines in a collection of global variables
Arcane code: Using abbreviatures/symbols in variables or functions, instead of self-descriptive names
Blind faith: Lack of checking of (a) the correctness of a bug fix or (b) the result of a subroutine
Boat anchor: Retaining a part of a system that no longer has any use
Busy spin: Consuming CPU while waiting for something to happen, usually by repeated checking instead of proper messaging
Caching failure: Forgetting to reset an error flag when an error has been corrected
Checking type instead of interface: Checking that an object has a specific type when only a certain contract is required
Code momentum: Over-constraining part of a system by repeatedly assuming things about it in other parts
Coding by exception: Adding new code to handle each special case as it is recognised
Double-checked locking: Checking, before locking, if this is necessary in a way which may fail with e.g. modern hardware or compilers.
Hard code: Embedding assumptions about the environment of a system at many points in its implementation
Lava flow: Retaining undesirable (redundant or low-quality) code because removing it is too expensive or has unpredictable consequences
Magic numbers: Including unexplained numbers in algorithms
Procedural code (when another paradigm is more appropriate)
Spaghetti code: Systems whose structure is barely comprehensible, especially because of misuse of code structures

Methodological anti-patterns

Copy and paste programming: Copying (and modifying) existing code rather than creating generic solutions
De-Factoring: The process of removing functionality and replacing it with documentation
Golden hammer: Assuming that a favorite solution is universally applicable
Improbability factor: Assuming that it is improbable that a known error becomes effective
Premature optimization: Optimization on the basis of insufficient information
Reinventing the wheel: Failing to adopt an existing solution
Reinventing the square wheel: Creating a poor solution when a good one exists

Configuration management anti-patterns

Dependency hell: Problems with versions of required products, specifically on UNIX/Linux
DLL hell: Problems with versions, availability and multiplication of DLLs, specifically on Microsoft Windows

Some Organisational Anti-patterns

Analysis paralysis: Devoting disproportionate effort to the analysis phase of a project
Cash cow: A profitable legacy product that often leads to complacency about new products
Continuous obsolescence: Devoting disproportionate effort to porting a system to new environments
Cost migration: Transfer of project expenses to a vulnerable department or business partner
Creeping featurism: Adding new features to the detriment of the quality of a system
Design by committee: The result of having many contributors to a design, but no unifying vision
Escalation of commitment: Failing to revoke a decision when it proves wrong
I told you so: When the ignored warning of an expert proves justified
Management by numbers: Paying excessive attention to quantitative management criteria, when these are inessential or cost too much to acquire
Management by perkele: Army-style management with no tolerance of dissidence
Mushroom management: Keeping employees uninformed and abused
Scope creep: Allowing the scope of a project to grow without proper control
Vendor lock-in: Making a system excessively dependent on an externally supplied component
Warm body: A person whose contribution to a project is in doubt, especially if taken on in panic
Single head of knowledge: SHOK applies when a single individual in the entire organization controls vital domain know-how or information on system internals.
Knight in shining armor: KISA happens when an individual who can do no wrong shows up on the scene and tries to fix everything without communicating what changes he/she has/will make and why.

References

Perl Design Patterns – A free online book
Brown, William J. (1998). AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis. John Wiley & Sons. ISBN 0471197130. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

External links