Design Patterns

Design patterns are typically categorized into three main groups based on their purpose:

Creational Patterns Deal with object creation mechanisms, trying to create objects in a manner suitable to the situation. Eg: Singleton, Factory Method, Abstract Factory, Builder, and Prototype patterns.
Structural Patterns These patterns focus on class and object composition. Eg: Adapter, Decorator, Proxy, Facade, Bridge, Composite, and Flyweight patterns.
Behavioral Patterns These patterns are concerned in defining how objects interact and communicate with each other. Eg: Observer, Strategy, Command, Chain of Responsibility, Iterator, State, Template Method, Visitor, Memento, and Mediator patterns.

Creational Patterns

Singleton

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

Factory

Defines an interface for creating an object, but allows subclasses to alter the type of objects that will be created.

Builder

Used when there are a sequence of steps that needs to be called while creating a class object, like when configuring a sequence of optional parameters.

Prototype

Creates new objects by copying an existing object, known as the prototype, during runtime.

Structural Patterns

Adapter

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

Decorator

Attaches additional responsibilities to an object dynamically, providing a flexible alternative to subclassing for extending functionality.

Proxy

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

Composite

TBD

Behavioral Patterns

Observer

when one object changes state, all its dependents are notified and updated automatically.