Object-oriented design anti-patterns
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*[[Functional decomposition]] - Classes that resemble the structure of programs creating using functional languages. [[William Brown 1998|WB]] | *[[Functional decomposition]] - Classes that resemble the structure of programs creating using functional languages. [[William Brown 1998|WB]] | ||
*[[God object]] - This anti-pattern occurs when an object / class does or knows too much. | *[[God object]] - This anti-pattern occurs when an object / class does or knows too much. | ||
| + | *[[Jumble]] - This anti-pattern describes a situation where "horizontal and vertical design elements are intermixed". This means that domain specific concepts are mixed with hierarchical concepts. [[William Brown 1998|WB]] | ||
*[[Object cesspool]] - This anti-pattern occurs when an object pool is used incorrectly in that the state of objects is not reset when they are returned to the pool. | *[[Object cesspool]] - This anti-pattern occurs when an object pool is used incorrectly in that the state of objects is not reset when they are returned to the pool. | ||
*[[Object orgy]] - This anti-pattern occurs when objects access each other internals directly rather than going through methods. | *[[Object orgy]] - This anti-pattern occurs when objects access each other internals directly rather than going through methods. | ||
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*[[Sequential coupling]] - This anti-pattern occurs when a class requires clients to call methods in a particular order. | *[[Sequential coupling]] - This anti-pattern occurs when a class requires clients to call methods in a particular order. | ||
*[[Spaghetti code]] - An adhoc structure that is difficult to extend and maintain. [[William Brown 1998|WB]] | *[[Spaghetti code]] - An adhoc structure that is difficult to extend and maintain. [[William Brown 1998|WB]] | ||
| + | *[[Stovepipe system]] - The integration of subsystems in an adhoc manner. [[William Brown 1998|WB]] | ||
*[[God object|The Blob]] - Equivalent to [[God object]], a very large class with a functional structure. [[William Brown 1998|WB]] | *[[God object|The Blob]] - Equivalent to [[God object]], a very large class with a functional structure. [[William Brown 1998|WB]] | ||
| + | *[[Vendor lock-in]] - Occurs in systems that are highly dependent on propitiatory architectures. [[William Brown 1998|WB]] | ||
*[[Yo-yo problem]] - This problem occurs with deep inheritance hierarchies, where a programmer has to keep looking up and down the hierarchy to understand the flow of control of the program. | *[[Yo-yo problem]] - This problem occurs with deep inheritance hierarchies, where a programmer has to keep looking up and down the hierarchy to understand the flow of control of the program. | ||
Revision as of 10:37, 23 September 2009
Object-oriented design anti-patterns describe bad design solutions to common problems. As such, they are essentially the opposite of conventional design patterns.
Many of these anti-patterns are closely related to common design maxims.
The following are common object-oriented design anti-patterns:
Architecture Anti-patterns
- Anemic Domain Model - This anti-pattern occurs when data and behaviour is separated in the domain model.
- BaseBean - This anti-pattern occurs when inheritance for implementation is used; that is a class inherits from another class not because it makes sense semantically but because it wants to use methods defined in the superclass.
- Boat anchor - A piece of software or hardware in the system that serves no useful purpose. WB
- Call super - This anti-pattern occurs when a superclass requires derived classes to call an overridden method.
- Circle-ellipse problem - This anti-pattern occurs when inheritance is not used correctly and the Liskov substitution principle is violated.
- Circular dependency - This anti-pattern occurs when there are two or more modules that depend directly or indirectly on each other.
- Constant interface - This anti-pattern occurs when an interface is used to declare constants but does not contain any methods.
- Cut and paste programming - Code reused by copying source from other locations. Increasing the likelihood of errors and decreases maintainability. WB
- Functional decomposition - Classes that resemble the structure of programs creating using functional languages. WB
- God object - This anti-pattern occurs when an object / class does or knows too much.
- Jumble - This anti-pattern describes a situation where "horizontal and vertical design elements are intermixed". This means that domain specific concepts are mixed with hierarchical concepts. WB
- Object cesspool - This anti-pattern occurs when an object pool is used incorrectly in that the state of objects is not reset when they are returned to the pool.
- Object orgy - This anti-pattern occurs when objects access each other internals directly rather than going through methods.
- Poltergeists - This anti-pattern occurs when temporary objects are used to initialize or call methods on more permanent objects.
- Sequential coupling - This anti-pattern occurs when a class requires clients to call methods in a particular order.
- Spaghetti code - An adhoc structure that is difficult to extend and maintain. WB
- Stovepipe system - The integration of subsystems in an adhoc manner. WB
- The Blob - Equivalent to God object, a very large class with a functional structure. WB
- Vendor lock-in - Occurs in systems that are highly dependent on propitiatory architectures. WB
- Yo-yo problem - This problem occurs with deep inheritance hierarchies, where a programmer has to keep looking up and down the hierarchy to understand the flow of control of the program.
Development & Management Antipatterns
- Continuous obsolescence - When technology changes so rapidly that the development can't keep up with current versions of the software. WB
- Golden hammer - When a single technique is applied "obsessively" to software problems. WB
- Lava flow - Dead and forgotten code that hardens and becomes unchanged as the system develops. Requires a change in development strategy. WB
- Mushroom management - This occurs when developers are separated from the end users. WB
See also
| Design anti-patterns | |
|---|---|
|
Anemic Domain Model | BaseBean | Call super | Circle-ellipse problem | Circular dependency | |
