Abstract Factory
Provides an interface for creating families of related or dependent objects without specifying their concrete classes.
Key participants:ClientAbstractFactoryConcreteFactoryAbstractProductProductAProductB
Source-based conversion: This page preserves the terminology and pattern descriptions from the supplied two-page Design Patterns Cheat Sheet. Page 1 contains Creational and Structural Patterns; page 2 contains Behavioral Patterns. fileciteturn1file0L2-L18 fileciteturn1file0L118-L128
Creational Patterns
Builder
Separates the construction of a complex object from its representation so that the same construction process can create different representations.
Key participants:DirectorBuilderConcreteBuilderProduct
Factory Method
Defines an interface for creating an object but lets subclasses decide which class to instantiate.
Key participants:ProductConcreteProductCreatorConcreteCreator
Prototype
Specifies the kinds of objects to create using a prototypical instance and creates new objects by copying this prototype.
Key participants:ClientPrototypeConcretePrototype1ConcretePrototype2
Singleton
Ensures a class only has one instance and provides a global point of access to it.
Key participants:Singleton-instance-Singleton()+GetInstance()
Structural Patterns
Adapter
Converts the interface of a class into another interface clients expect.
Key participants:ClientTargetAdapterAdaptee
Bridge
Decouples an abstraction from its implementation so that the two can vary independently.
Key participants:ClientAbstractionImplementorConcreteImplementorAConcreteImplementorB
Composite
Composes objects into tree structures to represent part-whole hierarchies.
Key participants:ClientComponentLeafComposite
Decorator
Attaches additional responsibilities to an object dynamically.
Key participants:ComponentConcreteComponentDecoratorConcreteDecorator
Facade
Provides a unified interface to a set of interfaces in a subsystem.
Key participants:FacadeSubsystem
Flyweight
Uses sharing to support large numbers of fine-grained objects efficiently.
Key participants:FlyweightFactoryFlyweightUnsharedFlyweightClient
Proxy
Provides a surrogate or placeholder for another object to control access to it.
Key participants:ClientSubjectProxyRealSubject
Behavioral Patterns
Chain of Responsibility
Avoids coupling the sender of a request to its receiver by giving more than one object a chance to handle the request.
Key participants:ClientHandlerConcreteHandler1ConcreteHandler2
Command
Encapsulates a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.
Key participants:ClientInvokerCommandConcreteCommandReceiver
Interpreter
Given a language, defines a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.
Key participants:ClientContextAbstractExpressionTerminalExpressionNonterminalExpression
Iterator
Given a language, defines a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.
Key participants:ClientAggregateConcreteAggregateIteratorConcreteIterator
Mediator
Defines an object that encapsulates how a set of objects interact.
Key participants:MediatorColleagueConcreteColleague1ConcreteColleague2ConcreteMediator
Memento
Without violating encapsulation, captures and externalizes an object's internal state so that the object can be restored to this state later.
Key participants:CaretakerOriginatorMemento
Observer
Defines a one-to-many dependency between objects so that when one object changes state all its dependents are notified and updated automatically.
Key participants:SubjectObserverConcreteSubjectConcreteObserver
State
Allows an object to alter its behavior when its internal state changes.
Key participants:ContextStateConcreteStateAConcreteStateB
Strategy
Defines a family of algorithms, encapsulates each one, and makes them interchangeable.
Key participants:ContextStrategyStrategyAStrategyB
Template Method
Defines the skeleton of an algorithm in an operation, deferring some steps to subclasses.
Key participants:AbstractClassConcreteClassTemplateMethod
Visitor
Represents an operation to be performed on the elements of an object structure.
Key participants:ClientVisitorConcreteVisitorElementConcreteElementAConcreteElementB
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