Summary of Design Patterns

• Creational Pattern: Involve object instantiation and all provide a way to decouple a client from the object it needs to instantiate
• Structural Pattern: Let you compose classes or objects into larger structures
• Behavioral Pattern: is concerned with how classes and objects interact and distribute responsibility

 

Pattern Type	Name	Use Cases
Creational	Singleton
	Prototype
	Factory
	Builder
Structural	Facade	1. Hides complexities of code from client providing easy to understand user interface (like a waiter with a restaurant menu)
	Proxy	1. To control access to specific objects (Warehouse and order fulfillment) 2. To defer creation of resource intensive objects until needed (image on web pages)
	Composite	1. Managing the running of multiple subprograms by their common methods
	Adapter	1. Conversion of the output of a function / api / program to fit to the input of another
	Decorator	1. Web page and web page decorators (authentication, authorization) to reduce number of components / codes used
Behavioral	Template Method	1. Used to consolidate two or more classes with similar functionalities
	Observer
	Chain of Responsibility	1. Used to handle streams of different requests like spam filtering system or oil refinery tower or symptom diagnosis
	State	1. Used to change the behavior of an object based upon the state that it's in at run-time