Creational
Creational patterns are ones that create objects for you, rather than having you instantiate objects directly. This gives your program more flexibility in deciding which objects need to be created for a given case.
Abstract Factory
groups object factories that have a common theme.
- drivers
- plugins
Builder
constructs complex objects by separating construction and representation.
- XMLSeriliaze, JosnSeriliaze?
Factory Method
creates objects without specifying the exact class to create.
- virtual function, or more exactly, duck type
Prototype
creates objects by cloning an existing object.
- ?
Singleton
restricts object creation for a class to only one instance.
- logging
- sql session
- cfg
Structural
These concern class and object composition. They use inheritance to compose interfaces and define ways to compose objects to obtain new functionality.
Adapter
allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.
- sqlalchemy
- nova hypervisor
- quantum plugin
Bridge
decouples an abstraction from its implementation so that the two can vary independently.
- ?
Composite
composes zero-or-more similar objects so that they can be manipulated as one object.
- ?
Decorator
dynamically adds/overrides behaviour in an existing method of an object.
- everywhere: @
Facade
provides a simplified interface to a large body of code.
- ?
Flyweight
reduces the cost of creating and manipulating a large number of similar objects.
- ?
Proxy
provides a placeholder for another object to control access, reduce cost, and reduce complexity.
- pasteDeploy
Behavioral
Most of these design patterns are specifically concerned with communication between objects.
Chain of responsibility
delegates commands to a chain of processing objects.
- ?
Command
creates objects which encapsulate actions and parameters.
- ?
Interpreter
implements a specialized language.
- ?
Iterator
accesses the elements of an object sequentially without exposing its underlying representation.
- ?
Mediator
allows loose coupling between classes by being the only class that has detailed knowledge of their methods.
- ?
Memento
provides the ability to restore an object to its previous state (undo).
- ?
Observer
is a publish/subscribe pattern which allows a number of observer objects to see an event.
- AMQP
State
allows an object to alter its behavior when its internal state changes.
- ?
Strategy
allows one of a family of algorithms to be selected on-the-fly at runtime.
- ?
Template
method defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.
- abstract class
Visitor
separates an algorithm from an object structure by moving the hierarchy of methods into one object.
- ?
Reference
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