Software design patterns

Singleton Pattern

Ensures a class has only one instance and provides a global point of access to it.

Factory Method Pattern

Defines an interface for creating an object, but let’s subclasses alter the type of objects that will be created.

Abstract Factory Pattern

Provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Builder Pattern

Separates the construction of a complex object from its representation so that the same construction process can create different representations.

Prototype Pattern

Specifies the kinds of objects to create using a prototypical instance and creates new objects by copying this prototype.

Adapter Pattern

Allows incompatible interfaces to work together by converting the interface of a class into another interface that a client expects.

Composite Pattern

Composes objects into tree structures to represent part-whole hierarchies. It lets clients treat individual objects and compositions of objects uniformly.

Proxy Pattern

Provides a surrogate or placeholder for another object to control access to it.

Decorator Pattern

Allows behavior to be added to an individual object, dynamically, without affecting the behavior of other objects from the same class.

Facade Pattern

Provides a simplified interface to a complex subsystem.

Flyweight Pattern

Reduces the cost of creating and manipulating a large number of similar objects.

Bridge Pattern

Decouples an abstraction from its implementation so that the two can vary independently.

Observer Pattern

Defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

Strategy Pattern

Defines a family of algorithms, encapsulates each one, and makes them interchangeable.

Command Pattern

Encapsulates a request as an object, thereby allowing for parameterization of clients with queues, requests, and operations.

Chain of Responsibility Pattern

Passes a request along a chain of handlers. Each handler can either handle the request or pass it to the next handler in the chain.

Mediator Pattern

Defines an object that encapsulates how a set of objects interact. This pattern promotes loose coupling by keeping objects from referring to each other explicitly.

Memento Pattern

Provides the ability to restore an object to its previous state (undo via rollback).

State Pattern

Allows an object to alter its behavior when its internal state changes. The object will appear to change its class.

Template Method Pattern

Defines the skeleton of an algorithm in the superclass but let’s subclasses override specific steps of the algorithm without changing its structure.

Visitor Pattern

Represents an operation to be performed on the elements of an object structure. It lets you define a new operation without changing the classes of the elements on which it operates.

Interpreter Pattern

Given a language, defines a representation for its grammar along with an interpreter that uses the representation to interpret sentences in the language.

Iterator Pattern

Provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation.