Anti-pattern
From LordMattWiki
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.
The final irony is the AntiPattern-AniPattern whereby the quest for a "deffinitive" leads to endless debate of the "is this a subset of that" nature. The result is caused by the Design by commitee anti-pattern but the final "war" will never end. As far as The Elephant Hunt is concerned any Anti-Pattern that is common or self explanitory will do. Remember KISS.
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[edit] Some recognised software development anti-patterns
- For a more comprehensive, alphabetical list, see Category:Anti-patterns.
[edit] 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
[edit] Design anti-patterns
- Category: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
- Category:Big ball of mud: A system with no recognisable structure
- Blob: see Category:God object
- Category:Gas factory: An unnecessarily complex design
- Category:Input kludge: Failing to specify and implement handling of possibly invalid input
- Category:Interface bloat: Making an interface so powerful that it is too hard to implement
- Category:Magic pushbutton: Implementing the results of user actions in terms of an inappropriate (insufficiently abstract) interface
- Category:Re-Coupling: Introducing unnecessary object dependency
- Category:Stovepipe system: A barely maintainable assemblage of ill-related components
- Category:Race hazard: Failing to see the consequence of different orders of events
[edit] Object-oriented design anti-patterns
AKA OOD Abuse.
- Category: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
- Category:God object: Concentrating too many functions in a single part of the design (class)
- Category:Object cesspool: Reusing objects whose state does not conform to the (possibly implicit) contract for re-use
- Category:Middle Man: 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
- Anemic Domain Model: The use of domain model without any business logic which is not OO because each object should have both attributes and behaviors.
- Category:Sequential Coupling: When a class requires you call methods in a particular order and will break if you don't. Methods whose name starts with Init, Begin, Start, etc. may be a tell tale symptom of this anti-pattern.
- Singletonitis: The overuse of the singleton pattern.
[edit] 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
- 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
- Category:Code momentum: Over-constraining part of a system by repeatedly assuming things about it in other parts
- Category: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.
- Category: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
- Category:Magic numbers: Including unexplained numbers in algorithms
- Category:Packratting: Consuming excess memory by keeping dynamically allocated objects alive for longer than they are needed
- Category:Spaghetti code: Systems whose structure is barely comprehensible, especially because of misuse of code structures
- Category:Superboolean logic: unnecessary comparison or abstraction of boolean arithmetic
[edit] Methodological anti-patterns
- Category:Copy and paste programming: Copying (and modifying) existing code rather than creating generic solutions
- Programming by permutation: Trying to approach a solution by successively modifying the code to see if it works
- De-factoring: The process of removing functionality and replacing it with documentation
- Golden hammer: Assuming that a favorite solution is universally applicable see Category:Silver bullet
- Category:Silver bullet: Assuming that a favorite or technical solution can solve a larger or process problem.
- Improbability factor: Assuming that it is improbable that a known error becomes effective
- Category:Premature optimization: Optimization on the basis of insufficient information
- Category:Reinventing the wheel: Failing to adopt an existing, adequate solution
- Category:Reinventing the square wheel: Creating a poor solution when a good one exists
[edit] Configuration management anti-patterns
- Category: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
- Extension conflict: Problems with different extensions to Mac OS attempting to patch the same parts of the operating system
[edit] Some organisational anti-patterns
- Category:Analysis paralysis: Devoting disproportionate effort to the analysis phase of a project
- Category:Cash cow: A profitable legacy product that often leads to complacency about new products
- Category:Continuous obsolescence: Devoting disproportionate effort to porting a system to new environments
- Category:Cost migration: Transfer of project expenses to a vulnerable department or business partner
- Category:Creeping featurism: Adding new features to the detriment of the quality of a system
- Category:Design by committee: The result of having many contributors to a design, but no unifying vision
- Category:Escalation of commitment: Failing to revoke a decision when it proves wrong
- See, I told you so: When the ignored warning of an expert proves justified, and this becomes the focus of attention
- Management by numbers: Paying excessive attention to quantitative management criteria, when these are inessential or cost too much to acquire
- Category:Management by perkele: Army-style management with no tolerance for dissent
- Category:Mushroom management: Keeping employees uninformed and abused
- Category:Scope creep: Allowing the scope of a project to grow without proper control
- Category: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
- Truck Number: The number of surplus personnel on a project. The number who can be hit by a truck before the project collapses.
